Contamination Engineering Design Guidelines

The preparation of an all-encompassing document such as this has an inherent set of limitations and shortcomings. Obviously, amongst the world of contamination experts, there exist wide varieties and differences of opinion with regard to recommended practices and methodologies. I have attempted, herein, to present what are considered to be "generally acceptable, Contamination Engineering practices" which are currently being implemented for spacecraft missions.

A number of world-recognized experts in the field of Contamination Engineering have contributed to the preparation of this document. The author wishes to extend sincere thanks to the esteemed contributors and reviewers of this document for their valuable suggestions and insights:

Mr. Gene Borson, consultant, formerly with the Aerospace Corporation Mr. Jack Barengoltz, with the Jet Propulsion Lab Dr. Peter Glassford, with the Lockheed - Martin organization Dr. Philip Chen, with NASA Goddard Space Flight Center Jack Triolo, with Swales and Associates Inc, formerly with NASA GSFC

1.0 INTRODUCTION

Times have changed.

Criteria associated with spacecraft "success" in the early days of the space program was often as basic as whether they acquired the proper orbit or if key components even functioned. Now, space technology as evolved to a point where spacecraft must be capable of adequately viewing distant galaxies, or detecting specific wavelengths of radiation from the sun, or measuring rainfall in South American rain forests. Times have changed, and with this change, comes the need for increasingly more sophisticated optics, thermal control, pointing and navigation control, along with the desire to extend performance lifetimes for spacecraft.

Along with the increasing complexity and sophistication of spacecraft and subsystems, comes the need for advancing the state-of-the-art for all supporting engineering disciplines, including Contamination Engineering.

The field of spacecraft Contamination Engineering has been growing quickly over the past 25 years. Years ago, spacecraft Contamination Engineering centered primarily around enforcing rules for workers in a cleanroom. Today s Contamination Engineering is comprised of numerous highly technical and sophisticated sub-disciplines ranging from evaluating surface contamination using laser imaging technology, through performing detailed computer modeling analyses for on-orbit spacecraft. The following chapters will enlighten and inform the reader on current methods and practices in the field of spacecraft Contamination Engineering.

1.1 Purpose

The purpose of this document is to provide the reader with a comprehensive description of the necessary elements involved in planning, designing, implementing, and verifying an adequate contamination control program for spacecraft and science instrument hardware. The document may be applied to all types of hardware development from individual components to complete subsystem assemblies, to any and all levels of science instrument hardware, up to and including entire integrated spacecraft and launch vehicles. Methods and technologies mentioned here represent the state-of-the-art in contamination control.

1.2 Scope

This document presents and describes generally accepted approaches and practices, currently employed by a number of space-related organizations such as NASA, DOD, major aerospace companies, and educational institutions. Industry renown experts have been consulted in the preparation of this document and many of the technical works produced by these experts are included in Section 4.0 Works Cited.

In the first part of this document, "THE PROCESS", the overall approach to spacecraft contamination, in concert with more detailed descriptions of subelements of this approach, are presented. The subsequent sections are organized in a project-related chronological fashion, beginning with guidelines for developing the initial set of contamination sensitivities and requirements for a spacecraft, and continuing with guidelines for development of necessary documentation. Then, discussions of design guidelines for each of the major spacecraft mission phases are presented. These phases include;

concept definition,
design,
fabrication,
asssembly,
integration,
testing,
transport and storage,
launch site,
launch vehicle/companion payload,
launch and orbit insertion,
on-orbit through end-of-life, and
post mission

In the "SYSTEMS CONSIDERATIONS" portion of this document, several topics are investigated more thoroughly in order to better acquaint the user with details on:

cleanroom operations
monitoring
analyses
laboratory investigations
interfacing with other subsystems
other related fields
new technologies

The organizational structure of this document has included the use of hypertext linking, which allows the user to access a variety of supplemental reference documents while reading the main-body document. Wherever possible, these reference documents, procedures, industry standards, technical papers, and lists of suggested reading, have been imbedded into the main document and may be accessed by the user at any time.

Finally, the "WORKS CITED" part of this document includes a listing of the primary reference documents, a grouping of related documents, and tables of technical specifications - all of which may be consulted for additional information.

1.3 Historical Examples of Spacecraft Contamination

Is contamination a real threat?

Excessive contamination of spacecraft and instruments can cause performance degradation and failure. It is useful to review and understand some of the past experiences with spacecraft contamination from the early years of the space program through present-day orbiting spacecraft.

The NASA GSFC Contamination Engineering Group (Code 724.4) has assembled a brief historical summary of how contamination has caused problems for spacecraft performance. These examples are presented in the following section.

1.3.1 Spacecraft Performance Failures/Degradation Due to Contamination

Table 1.3.1-1 presents an overview of the more prominent incidences of spacecraft problems due to contamination.

*Table 1.3.1-1 Summary of Spacecraft Contamination Problems*
Spacecraft Performance Failures and Degradation Due to Contamination
Spacecraft	Contamination Problem
OGO-6 (1969)	Excessive build-up on QCMs due to solar array outgassing
Nimbus IV (1970)	Water build-up on cooled detectors caused failure of a spectrometer early in the mission
OSO-8 (1971)	Lyman-Alpha capability lost after 9 days due to electronics box outgassing
NOAA, TIROS, and DMSP (1970s)	Thermal control problems due to outgassing and engine plume deposition
RCA and GE Spacecraft (1970s)	Thermal control problems due to contamination build-up on OSRs.
Skylab and Voyager (1970s)	Visual observations of particle clouds on Skylab; star tracker interference due to particle clouds on both missions
LES 8 and 9 (1970s)	Plumes from retro rockets impinged on payloads during stage II separation.
SCATHA (1979)	Continual accumulations of 200 Angstroms/year were permanently "fixed" due to photopolymerization
SMM (1980)	Improved version of OSO-8 Lyman-Alpha instrument lasted 40 days before failing due to contaminant build-up.
SBUV (1980s)	Accretion and photopolymerization of contaminants on scatter plate calibration system.
DE A&B (1981)	Vent effluents deposited on solar-lit radiator surface, causing permanent deposition and high temperatures.
Landsat (1980s)	Degradation of 500-600 nm channel shortly after launch, due to contaminant build-up.
IECM (1980s)	Measured Shuttle contamination levels; used to identify problems with particle clouds and payload outgassing.
CMP (1980s)	Measured contaminant accretions in the Shuttle bay; measured materials erosion rates due to atomic oxygen exposure
SUSIM (1980s)	Internal box outgassing caused arcing and electronics burn-out, and failure of the instrument mission.
HRTS/Sunlab (1980s)	Immediate loss of 1200-1600 Angstrom bandwidth due to build-up of silicones, caprolactan, and DOP.
INSAT1B (1983)	Visible range instrument degraded 40% (in throughput).
HST (1990s)	WFPC- I UV capability lost due to contamination build-up and UV (solar and/or earth albedo) exposure.

1.4 Overall Suggestions

Although specific technical "lessons learned" are scattered throughout this discourse on Contamination Engineering, it may be useful, as a summary, to highlight the underlying basic recommendations associated with this discipline:

Keep up with the latest research; this discipline is ever-evolving.
Consult the experiences of previous missions and spacecraft development
programs.
Consult industry-recognized experts for ideas and assistance.
Ascertain the degree of contamination sensitivity of your instruments and
spacecraft, as early as possible.
Set-up Contamination Engineering as an officially recognized project
"subsystem" or "discipline" (similar to other subsystems and disciplines
such as thermal, mechanical, electrical, etc.).
Document all the contamination requirements and plans, starting with a
comprehensive Contamination Control Plan.
Do not hesitate to set-up and perform analyses and laboratory
investigations to study and verify contamination assertions.

1.5 Acronyms

APML

Ascent Particle Monitor

Aft Shroud

ASTM

American Society For Testing and Materials

CCD

Charge Coupled Device

CCIP

Contamination Control Implementation Plan

CCP

Contamination Control Plan

CDR

Critical Design Review

CMP

Contamination Monitor Package

COBE

Cosmic Background Explorer

CQCM

Cryogenically Controlled Quartz Crystal Microbalance

CVCM

Collected Volatile Condensable Material

DOD

Department of Defense

ESD

Electrostatic Discharge

EUVE

Extreme Ultraviolet Experiment

FUV

Far Ultraviolet

GFE

Government Furnished Equipment

GOES

Geostationary Operational Environmental Satellite

GRO

Gamma Ray Observatory

GSE

Ground Support Equipment

GSFC

Goddard Space Flight Center

HST

Hubble Space Telescope

ICD

Interface Control Document

IES

Institute of Environmental Sciences

IOCM

Interim Operational Contamination Monitor

Infrared

JPL

Jet Propulsion Laboratory

JSC

Johnson Space Center

LDEF

Long Duration Exposure Facility

LEO

Low Earth Orbit

LSCCP

Launch Site Contamination Control Plan

Molecular Adsorbers(s)

MLI

Multi-Layer Insulation

MSFC

Marshall Space Flight Center

NVR

Non-Volatile Residue

PDR

Preliminary Design Review

Principal Investigator

PPM

Parts Per Million

QCM

Quartz Crystal Microbalance

Quantum Efficiency

R or r

Reflectance

RQMT

Requirement

SAW

Surface Acoustic Wave

Systeme International (International System of Units)

SOHO

Solar Heliospherical Observatory

TEC

Thermo-Electric Cooler

TML

Total Mass Loss

TOWS

Temperature-Controlled Optical Witness Sample

TQCM

Temperature-Controlled Quartz Crystal Microbalance

TRMM

Tropical Rainfall Measuring Mission

Thermal Vacuum

UARS

Upper Atmosphere Research Satellite

USCS

United States Customary System (of units)

Ultraviolet

VCM

Volatile Condensable Material

WFPC

Wide Field Planetary Camera

XTE

X-Ray Timing Explorer

1.6 Definitions

Cleanroom	Room in which the concentration of airborne particles is controlled to a specific limit.
Contamination	An unwanted material or substance that causes degradation in the desired function of an instrument or flight hardware.
Contamination Control	Organized action to control the level of contamination.
Fiber	A particle whose length-to-width ratio exceeds 10:1 with a minimum length of 100 microns.
Gross Cleaning	Cleaning hardware surfaces in a normal work area to visual inspection standards.
Molecular Contamination	Unwanted presence of substances in film, gaseous, or droplet type forms. (e.g. visible film deposited, due to nonmetallic materials outgassing, on an optical surface).
Nitrogen Purge	Cavity, container or area filled with clean, dry nitrogen in order to displace oxygen or moisture or a constant flow used to maintain a positive pressure between the cavity and the surrounding environment.
Non-Volatile Residue	Soluble material that causes degradation in the desired function of an instrument or flight hardware.
Particle	A small quantity of solid or liquid material with definable shape or mass with a length-to-width ratio less than or equal to 10:1.
Particle Contamination	Unwanted presence of substances in film, gaseous, or droplet type forms. (e.g. visible film deposited, due to nonmetallic materials outgassing, on an optical surface).
Particle Size	Expressed as the apparent maximum linear dimension or diameter of the particle.
Particle Contamination	The unwanted presence of substances, usually individually definable in terms of shape, length, width, and depth. (e.g. dust particles on a mirror).
Particle Size	Expressed as the apparent maximum linear dimension or diameter of the particle.
Visibly Clean	A clean surface as seen without optical aids (except corrected vision) when measured by a specific method. For this project, surfaces should be tested from a distance of 6 to 18 inches using black and white light >100 ft. candles of power.
Precision Cleaning	A cleaning procedure done in a controlled environment to attain a specific level of cleanliness. This procedure follows gross cleaning.
Sensitive Surfaces	Any surface of flight hardware that must meet a specified cleanliness level to assure the minimum performance levels.
Solvent Flushing	Method of cleaning surfaces with a stream of filtered solvent under pressure, which is directed against a surface to dislodge and rinse away any contaminating material.
Solvent Wash	A quantitative method of verifying MIL-STD-1246C molecular cleanliness levels by measuring molecular contamination in a solvent that was washed over a surface.
Surface Cleanliness Level	An established level of maximum allowable particulate and/or NVR contamination ranging from visibly clean to specific MIL-STD-1246C levels (e.g., level 500B)
Swab Sample	A qualitative method of identifying contaminants by analyzing the residue on a solvent-soaked swab that was wiped over the surface.
Tape Lift Sampling	A quantitative method of verifying MIL-STD-1246C particulate cleanliness levels by measuring particulate contamination on a sample of tape that has come in contact with a surface.

2.0 THE PROCESS

So how is it done?

This part of the document is basically a "How To..." manual.

The main issue to be addressed in this section is "How does one handle Contamination Engineering for a spacecraft or instrument?". This "PROCESS" section has been written such that a contamination engineer can look at one or all steps in spacecraft development and learn about which contamination actions are recommended. Keep in mind that each spacecraft program is unique and special requirements and planning may be required in addition to what is presented herein. Good Luck!

2.1 General Approach To Spacecraft Contamination Engineering

Spacecraft Contamination Engineering has been an expanding field of interest over the past few decades, due to the increasing complexity and sophistication of today s variety of missions. Spacecraft are now being designed to view a wide range of space and earth targets, at different magnifications, wavelengths, and altitudes.

The optical, thermal control, and guidance systems for these spacecraft rely upon maintenance of the original design properties of the systems. A build-up of contamination deposition on any of these systems may alter the optical viewing, data acquisition and thermal maintenance capabilities of the systems. Lenses must remain "unfogged" to ensure clear imaging and sensing; baffles must remain free of particulates to minimize scattering; external paints and blankets must be kept free of contaminants to ensure maintenance of thermal control properties (absorptance, reflectance, emmitance, etc.).

In support of this effort to ensure cleanliness of spacecraft and instrument systems, the engineering discipline of Contamination Engineering was developed. Contamination Engineering, as a discipline, consists of developing contamination requirements, designing an appropriate contamination control program to meet these requirements, and finally to implement the contamination control program and verify that the requirements have been met. Spacecraft Contamination Engineering applies not only to the development of an entire spacecraft, but may also be applied to the development of any individual instrument, subsystem, or component.

The basic logical approach to Contamination Engineering for a spacecraft is:

Gather as much information as possible on the spacecraft performance goals and design requirements.
Identify sensitive surfaces, components, and systems and assign quantitative contamination requirements for each element.
Evaluate information, history and flight data from previous missions; apply "lessons learned" to current program.
Design, document, and implement a comprehensive contamination control program for the spacecraft beginning with the concept definition phase, and continuing on through fabrication, assembly, integration and test, transport, launch, and on-orbit, and post-mission or retrieval mission phases.
Study spacecraft design and identify potential "problem" areas. (e.g., acceptable vs. non-acceptable vent locations).
Perform trade-off studies to evaluate technical adequacy, cost and schedule impacts, of proposed contamination control measures (e.g. performing bakeouts of components vs. incorporating Molecular Adsorbers).
Perform laboratory testing whenever needed, to assess contamination potentials of materials, and to evaluate contamination levels versus performance degradation.
Perform analytical modeling, whenever needed, to predict expected contamination deposition levels for sensitive surfaces.
Perform cleaning, vacuum bakeouts, and implement protection devices (covers, bags, containers, etc.) to minimize resultant contamination levels.
Perform adequate monitoring and verification of contamination levels on and near the spacecraft during all buildup and launch readiness mission phases.
Monitor launch and on-orbit contamination environments, and/or evaluate the performance of spacecraft systems to determine effects of contamination.
Develop "lessons learned" list for implementation on follow-on projects.

It should be stressed that implicit within the above-defined approach is the concept of iteration. The approach to contamination engineering for a spacecraft is an iterative process! Look upon each of these steps as being part of a flowchart, with arrows going from one box to another box (or several other boxes), with decision points, and with arrows directing the reader back to re-performing previous steps, until results are satisfactory.

Of course, the above-described approach must be adjusted to fit the actual requirements of each spacecraft, depending on the complexity of the spacecraft, and on the contamination sensitivities for the critical elements. The following chapter provides the basic guidelines for defining contamination control requirements for various types of spacecraft.

2.2 Guidelines For Contamination Control Requirements Definition

The following subsections present some basic guidelines for developing the basic set of contamination control requirements for spacecraft. For organizational purposes, the sections have been delineated into three categories: spacecraft with low, medium and high sensitivities to contamination.

2.2.1 Spacecraft with Low Contamination Sensitivity

Generally, spacecraft considered to have a "low" sensitivity to contamination are those with minimal optics, or very insensitive optics (e.g. few elements, no moving mechanisms), and relatively flexible thermal control requirements. For example, looking at previous spacecraft which could be considered to have a low contamination sensitivity, XTE and GRO are representative projects. Consult the program documentation and contamination control plans for these spacecraft for details on the requirements and associated operations performed for these spacecraft.

In order to provide a "rough" example of the most basic level of requirements for a low sensitivity spacecraft, the following table is offered. Keep in mind that each spacecraft and instrument should be evaluated on a case-by-case basis. Of course, these are only basic level requirements; there is a pyramid of sub-requirements which must be derived under each of these basic requirements.

*Table 2.2.1-1 Example of Low Sensitivity Spacecraft Contamination Requirements*
Requirement Category	Quantitative Level

Cleanroom Needed	Class 100,000 per Fed. Std. 209
Optics Allowable Molecular (EOL)	Level B per Mil. Std. 1246
Non-optics Allowable Molecular (EOL)	Level C per Mil. Std. 1246
Optics Allowable Particulate (EOL)	Level 750 per Mil. Std. 1246
Non-optics Allowable Particulate (EOL)	Level 750-1500 per Mil. Std. 1246

2.2.2 Spacecraft with Medium Contamination Sensitivity

This category represents those spacecraft which may have optical and thermal control systems which may be adversely affected by an average amount of contamination. The requirements for a spacecraft with medium contamination sensitivity will generally be achievable through design and implementation of an adequate contamination control program. For illustration purposes, it may be useful to look at previous missions which could be considered "medium sensitivity" spacecraft. The NASA programs, GOES, Landsat, UARS and GGS, are different examples of medium sensitivity missions. Please consult the contamination control plan for each of these projects, for details on all the essential contamination requirements.

In order to provide a "rough" example of the most basic level of requirements for a medium sensitivity spacecraft, the following table is offered. Medium sensitivity spacecraft are often the most complex to evaluate. In a medium sensitivity spacecraft, there may be 3 or 4 components or subsystems which are relatively sensitive to contaminants, while the rest of the spacecraft is totally insensitive.

Usually, the contamination engineer must carefully evaluate cross-contamination potentials and design a program which typically includes categorizing all elements with "cross-contamination potential" as sensitive. The potential contamination sources from those parts of a spacecraft which are not sensitive must often be controlled to prevent contamination of other parts of the spacecraft which are sensitive. In this regard, the necessity to fully explore the potentials for mass transport from one area of a spacecraft to another area becomes important. Of course, depending on the type of contamination involved (molecular vs. particulate) and the mission phases involved (cleanroom cross-contamination, launch/ascent venting, on-orbit self-contamination), the types of analyses needed are different. As a general rule, for any spacecraft which has these varying degrees of sensitivities and sources, comprehensive analytical studies to assess potential depositions must be performed.

Keep in mind that each spacecraft and instrument should be evaluated on a case-by-case basis. Of course, these are only basic level requirements; there is a pyramid of sub-requirements which must be derived under each of these basic requirements.

*Table 2.2.2-1 Example of Medium Sensitivity Spacecraft Contamination Requirements*
Requirement Category	Quantitative Level
Cleanroom Needed (when optics are exposed)	Class 10,000 or better per Fed. Std. 209
Cleanroom Needed (other operations)	Class 100,000 per Fed. Std. 209
Optics Allowable Molecular (EOL)	Level A per Mil. Std. 1246
Non-optics Allowable Molecular (EOL)	Level B per Mil. Std. 1246
Optics Allowable Particulate (EOL)	Level 300 per Mil. Std. 1246
Non-optics Allowable Particulate (EOL)	Level 500-750 per Mil. Std. 1246

2.2.3 Spacecraft with High Contamination Sensitivity

Spacecraft with "high" contamination sensitivities are primarily those which rely on optical sensing and imaging and/or spacecraft which have very strict temperature control requirements. These may be comprised of scientific (Earth, space, and solar viewing) as well as DOD military missions. For illustrative purposes, the HST, EUVE, SOHO and COBE programs are solid examples of highly sensitive spacecraft projects. Substantial contamination control efforts were required for all of these projects. Please consult the contamination control plans for these projects for additional details.

Often, too, it has been determined that if just one spacecraft optic or system has an extremely severe contamination sensitivity, that system will drive the contamination requirements for the entire spacecraft, in order to prevent cross-contamination. Thus, an otherwise "medium" sensitivity spacecraft may well be forced to assume the necessary precautions and planning associated with a highly sensitive spacecraft.

Highly sensitive spacecraft usually require design and implementation of a strict contamination control program, with ongoing monitoring and cleaning. Also, for many highly sensitive spacecraft, the application of state-of-the-art contamination control methods and devices may be required. Special instrument purging, intensive thermal vacuum bakeouts, use of mechanical contamination covers, use of molecular adsorbers, and the use of on-orbit cleaning devices may be considered for implementation on highly sensitive spacecraft.

Key characteristics which may be indicative of a highly sensitive spacecraft include the following:

Mission characteristics:
Low altitude (< 1000 kilometers) increases the probability of self-contamination caused by return flux of molecules, and increased risk of atomic oxygen erosion of materials.
Solar UV exposure (and some levels of earth albedo UV exposure) increase the risk of photopolymerization of contaminants.
UV instruments are typically very sensitive to even small amounts of contaminants.
IR instruments are typically sensitive to particulate and thick layers of molecular or water build-up on cryogenically cooled surfaces.
Cooled detector systems are susceptible to accumulating water and contaminants, and may experience subsequent performance degradation due to these accumulations.
Spacecraft lifetime requirements may require more serious contamination control measures.
Spacecraft design characteristics:
Lenses
Mirrors
Detectors
Instrument calibration systems and targets
Baffle systems
Cryogenically cooled systems
Thermal control surfaces, coatings and passive coolers

Also, as a very general "rule of thumb", spacecraft optical systems which view at Ultraviolet (UV) wavelengths are usually sensitive to even small amounts of molecular contaminant deposition. This is due not only to the short UV wavelength, but also to the phenomenon known as UV photopolymerization. Molecular contamination on a surface, when exposed to UV radiation will often photopolymerize, which means the contaminant will permanently "fix" itself to the substrate surface and darken in color. In addition, the presence of UV radiation can increase the deposition rates of certain outgassing materials, and cause deposition to occur at higher surface temperatures than expected. Evidence of serious performance degradation of UV instruments, due to these phenomena has been found on a variety of past spacecraft.

Another general "rule of thumb" is that many optical systems viewing in the Infrared (IR) portion of the spectrum are considered sensitive to particulate contamination and relatively thick layers of molecular and water accumulations. The "length" of IR wavelength radiation can be in the same general range of many common particulates (such as dust); the incoming IR radiation will interact with particles on the surfaces of baffles, lenses, mirrors, etc. thus causing straylight and scattering problems, resulting in poor detection of the actual radiation levels and targets. For example, straylight around an instrument aperture can interfere with the sensing and rejection of bright out of FOV objects. If the IR instrument is cryogenically cooled, there is a higher chance that thick layers of molecular and water contamination may build up on optical surfaces, causing inaccurate radiation detection.

As mentioned under the Medium Sensitivity category, the cross-contamination issue is extremely critical, and becomes even more so for the Highly Sensitive spacecraft or instrument. Usually, the contamination engineer must carefully evaluate cross-contamination potentials and design a program which typically includes categorizing the entire spacecraft as Highly Sensitive. Detailed computer modeling analyses for particulate and/or molecular contaminant transport and deposition are usually a required program element for any Highly Sensitive spacecraft or instrument system.

In order to provide a "rough" example of the most basic level of requirements for a high sensitivity spacecraft, the following table is offered. The actual full set of requirements for a high sensitivity spacecraft is very detailed. Keep in mind that specific spacecraft may vary from these levels by considerable amounts and each spacecraft and instrument should be evaluated on a case-by-case basis. And of course, these are only basic level requirements; there is a pyramid of sub-requirements which must be derived under each of these basic requirements.

*Table 2.2.3-1 Example of High Sensitivity Spacecraft Contamination Requirements*
Requirement Category	Quantitative Level
Cleanroom Needed (when optics are exposed)	Class 100 per Fed. Std. 209
Cleanroom Needed (other operations)	Class 10,000 per Fed. Std. 209
Optics Allowable Molecular (EOL)	< 100 Angstroms
Non-optics Allowable Molecular (EOL)	< Level A per Mil. Std. 1246
Optics Allowable Particulate (EOL)	< Level 100 per Mil. Std. 1246
Non-optics Allowable Particulate (EOL)	Level 200-300 per Mil. Std. 1246

2.3 Guidelines For Contamination Control Documentation

With the recent growth and increasing demands placed on the field of Contamination Engineering, it has become essential to fully plan and document a complete end-to-end contamination control program for each spacecraft.

The first and most important step in any contamination control program is to define all contamination requirements in a Contamination Control Plan (CCP). The CCP is the governing document for all contamination requirements and should be kept up-to-date throughout the program. All other subsidiary documents are based on the overall requirements in the CCP. The subsidiary documents generally required for projects are numerous and cover a wide range of topics, from personnel cleanroom procedures, to thermal vacuum bakeout test plans.

The following subsections describe the necessary contamination control documentation.

2.3.1 Contamination Control Plan

The CCP is the most important contamination control document for any program. It is recommended that all spacecraft projects develop an officially recognized CCP, as part of the basic documentation hierarchy. This applies to all types of spacecraft (low, medium and high sensitivity).

The CCP should contain all contamination-related requirements beginning with the overall end-of-life allowable deposition requirements (for both particulate and molecular contamination), for all sensitive surfaces and subsystems. The importance and complexity of this task is enormous. Often, this "starting point" is the most difficult to ascertain. The overall allowable deposition levels are tied directly to the performance goals of the instrument and mission. And, although the principal scientist may be able to immediately state the performance goals of the mission, the correlation of these goals to such parameters as number of particles, or thickness of films on each individual sensitive surface is often unclear. It is often necessary for the contamination engineer to work closely with the scientists in developing the contamination requirements. In addition, numerous analytical studies and laboratory studies may be necessary to determine the proper allowable levels.

From the overall end-of-life allowable deposition requirements, the breakdown of specific allowable contamination levels, at progressive points in the build-up, integration, testing, launch readiness process, and on-orbit mission phases should be derived. This breakdown is often called a contamination "budget" and should be clearly presented in the CCP.

The CCP should also specify when and by what methods the various contamination requirements will be verified. It is good contamination practice to include frequent verification of contamination levels so that problems associated with excess contamination levels can be identified and solved as soon as possible.

The CCP should also present the overall plan for controlling contamination, from fabrication and assembly, throughout integration and testing, and continuing with launch site, launch, and on-orbit plans. Any laboratory and analytical support should also be identified in the CCP. All necessary supporting documents should be referenced in the CCP.

For examples of CCPs which have been developed and effectively implemented for spacecraft programs, the following programs are cited:

UARS CCP
GGS
HST
TRMM
COBE

2.3.2 Supporting Contamination Documentation

Based on the contamination requirements defined in the CCP, a spacecraft project must also either develop or "borrow" supporting documents in order to implement the program defined in the CCP. The following documentation list represents the type of supporting documents which may be required for a project:

CCP Implementation Plan
Hardware Cleaning Procedures
Hardware Cleanliness Verification Procedures
Molecular Wash Method
Molecular Wipe Method
Particulate Tape Lift Sampling
Particle Counting Method
Optical Measurement Methods
Actual instrument throughput/performance measurements
Witness Plate Measurements
Cleanroom Personnel Training/Certification Documents
Cleanroom Personnel Operations Requirements
Cleanroom Operating Procedures
Approved Materials Lists
Cleanroom Monitoring Methods
Purging Plans
Hardware Bagging Requirements
Contamination Protection Methods
Material/Hardware Outgassing Certification Plans
Thermal Vacuum Bakeout Plans
Transportation/Storage Cleanliness Plans
Launch Vehicle/Companion Payload Interface Documents
Launch Site Cleanliness Requirements
Launch/On-orbit Contamination Requirements
Testing Results Reports (Thermal Vacuum Bakeouts, Vibration Testing, Functional Testing, etc.)
Hardware Certification Logs and Anomaly Reports
Lessons Learned Summary Report

The basic standards and practices, and some procedural documents already exist in open literature and are controlled by various technical societies (ASTM, IES, etc.). A spacecraft project may utilize these documents and reference them in the higher level documents, rather than develop completely new documents. Section 4.3 of this document contains a detailed list of commonly used specifications and standards.

2.4 Basic Design Guidelines

The following subsections are devoted to explaining the Contamination Engineering design guidelines associated with spacecraft development. These design guidelines are presented in a chronological (based on mission phase) format from concept definition through the entire spacecraft development process, culminating in launch and post-mission phases.

2.4.1 Concept Definition and Early Program Phases

During the concept definition and early program phases of spacecraft development, the Principal Scientist or Principal Investigator is largely responsible for designing the mission. However, should the Contamination Engineer be asked to participate in this phase of the program, there are a number of key items to consider. The Contamination Engineer should review the concept and preliminary spacecraft design and identify the contamination critical components and systems. The Contamination Engineer may also assist with the development of the first-cut allowable contamination requirements, based on mission performance goals. This would also be an ideal point in the program (as early as possibly) to consider the implementation of contamination protective enclosures and devices, innovative methods for minimizing contamination (such as molecular adsorbers), and possibly the use of on-orbit clean-up techniques. The Contamination Engineer should also be prepared to outline the overall contamination control program envisioned for the spacecraft.

It is also possible that, during these early program phases, a number of preliminary analytical modeling studies or experimental investigations may be performed to aid in assessing the basic design and performance goals for the mission.

2.4.1.1 Concept Definition and Early Program Phases General Recommendations

The following table presents a few of the general recommendations associated with Contamination Control efforts during the early program phases.

*Table 2.4.1.1-1 Concept Definition and Early Program Phases Recommendations*
Category	General Recommendations
Project Recognition of Contamination Engineering	Project Management should be advised that Contamination Engineering must be officially recognized and tracked as its own discipline or subsystem (often it is categorized as a subsystem, similar to Thermal Engineering). It should not be grouped with another discipline, and it should not be merely considered a "housekeeping" type function.
Participation of the Contamination Engineer	It is crucially important for the Contamination Engineer to participate in early meetings and documentation development starting at the very early program phases. Be proactive!
Provide Inputs to Concept Discussions	The Contamination Engineer should actively participate and provide opinions to the Principal Scientists and program management on behalf of contamination issues

2.4.2 Spacecraft Design Phase

The Contamination Engineer participates substantially in the preliminary and critical design phases of spacecraft development. There are a number of essential tasks which must be performed during the design phase.

Although, at this point in the program, most of the work involves paper, drawings, and documentation, this has proven to be one of the most important phases of the program, requiring diligent attention to the planning of contamination control. A well-planned and organized contamination control plan which is developed and implemented during the design phase of a spacecraft program, helps to ensure overall mission success. The following list identifies the most essential tasks to be performed during this phase of spacecraft development:

Identification of contamination critical surfaces, assemblies, components, and subsystems.
Derivation (based on performance requirements) and final assignment of quantitative allowable contamination levels (molecular and particulate) for each of the sensitive surfaces and other hardware surfaces.
Derivation and final assignment of other contamination-related requirements such as humidity restrictions, hydrocarbon exposure, specific limits on materials (sprays, silicones, etc.).
Complete review of the spacecraft design (at various points from preliminary design through critical design) to identify potential threats to instrument success.
Review and assessment of spacecraft vent and thruster locations, and impacts to contamination critical elements. Emphasis on placing and directing vents away from critical areas is extremely important.
Review and approval of complete materials list for all spacecraft parts; perform specific materials outgassing testing as required. Evalute rate constants and assess ways to devolatilize materials.
Evaluate pressure build-up inside electronics boxes; ensure vent design of boxes minimizes the potential for high pressure build-up which can cause high voltage arcing and serious failure/safety problems.
Performance of detailed analytical modeling studies (both molecular and particulate) to predict contamination transport and deposition on critical surfaces.
Analysis of impacts of solar UV exposure on surfaces, coatings, and contaminants
Analysis of atomic oxygen environment, and predictions of atomic oxygen materials erosion (and subsequent effects).
Develop and publish the Preliminary Spacecraft Contamination Control Plan.
Develop and publish supporting contamination documentation (operating plans, procedures, test plans, etc.).

2.4.2.1 Design Phase Recommendations

The following table addresses some of more common categories involved in the spacecraft design phase, and the associated contamination control general recommendations for each category. Keep in mind that each spacecraft program is unique and many of these recommendations may not apply.

*Table 2.4.2.1-1 Design Phase Recommendations*
Category	General Recommendations
Materials Selection	Non-metallic materials shall meet TML/VCM criteria set forth in the NASA SPR-0022A specification, as a minimum. Any extensive use of a specific non-metallic material shall be evaluated on a case-by-case basis, for acceptability. Materials testing on non-metallic materials for which the TML/VCM data is unknown or not representative must be performed. All materials shall be non-shedding, non-flaking, non-particle generating; testing shall be performed on any questionable materials. All external materials shall have low reactivity to atomic oxygen. A complete materials list shall be generated, and reviewed by the responsible Contamination Control Engineer for acceptability.
Mechanisms, Motors, etc.	These items shall be designed to be enclosed or self-contained (sealed) to the greatest extent possible. These items shall undergo bakeout and certification, prior to integration, to lower potential contamination levels. These items shall be functionally tested for particle generation potential. Any vents on these items shall be designed so that effluents will not impinge upon optics/optical path or be ingested into the instrument optical cavity.
Shields, Baffles, and Barriers	These items shall be included in the design, when necessary, to protect sensitive optics from contamination.
Thermal Control Surfaces	These items shall be designed to have low contamination generation characteristics. Paints, coatings, blankets, etc. shall be fabricated with low outgassing and low particle generating materials. All surfaces shall be designed to be cleanable and verifiable. External thermal control coatings shall have low reactivity to atomic oxygen. MLI blankets shall be assembled using single filament dacron netting (low particle generating). External MLI surface must be cleanable and verifiable. MLI blankets shall be sealed on all edges and taped (using approved low outgassing tape) around protruding components. Vents on MLI blankets must be selected with regard to impacts on surrounding optics. Vents on MLI blankets shall include a filtering layer to prevent particles from migrating to the exterior.
Vents	Vent locations (on components, motors, electronics boxes, etc.) shall be determined with regard to potential to contaminate sensitive elements of the spacecraft. Modeling analyses to assess vent contamination contributions are recommended. Filters on vents are recommended. Use of molecular adsorber materials in the vents are recommended to reduce the amount of contaminants propagated to the external spacecraft volumes.
Surface Finishes	Surface finishes such as black anodize finishes shall be inspected and verified on all components and parts. Tape lift methods may be used to assess particle generation from these parts. Any improperly anodized parts must be reanodized.

2.4.3 Hardware Fabrication Phase

The fabrication phase of spacecraft development is the earliest phase associated with flight hardware development and usually entails the cutting, drilling, soldering, etc. of metal, plastics, composite materials, etc. to form spacecraft parts and subassemblies. Generally, these activities are inherently "dirty" and are carried out in non-cleanroom environments.

2.4.3.1 Fabrication Phase Recommendations

There are a number of basic recommended contamination control practices to be followed during this fabrication phase. These include:

*Table 2.4.3.1-1 Fabrication Phase Recommendations*
Category	General Recommendations
Personnel Training	Set-up and provide a mandatory personnel training course where the specific requirements (handling, personnel, operations, cleanliness, etc.) for the fabrication phase of the program are thoroughly explained.
Soldering, Drilling Lubricants, etc.	Assure that any soldering compounds, drilling lubricants, surface finishes used during the fabrication process are on the approved materials list (for low outgassing and low particle shedding compatibility) and, furthermore, assure that all of these items are cleanable.
Debris Generated During Fabrication	Assure that to the greatest extent possible, fabrication debris (such as metal chips, flakes, fibers, etc.) are cleaned up or brushed off the flight hardware, as soon as they are generated.
Close-Out of Subassemblies During Fabrication	Assure that any parts or subassemblies which are permanently "sealed-up" are first thoroughly cleaned prior to the closure process.
Surface Finishes	Perform integrity and quality testing (such as solvent compatibility and tape lift sampling) on parts, surface finishes, etc. to ensure they will not generate contamination later in the program.
Post-Fabrication Cleaning	After fabrication is completed, perform a thorough cleaning of all hardware (removing both particles and residues); double bag hardware and store or transport to the next assembly phase.
Optics Fabrication	Generally, optics fabrication is a completely separate category from structural fabrication. Optics are generally fabricated in well-controlled cleanroom environments and must be treated with critical contamination concern.

2.4.4 Hardware Assembly Phase

The assembly phase represents the starting point for "hands-on" contamination control in most spacecraft development programs. Assembly entails the formation of spacecraft components, instruments, subsystems, etc. and can range from simple mechanical assemblies to very complicated full-scale instrument assemblies.

2.4.4.1 Assembly Phase Recommendations

The following table includes some of the more typical recommendations associated with the assembly phase of spacecraft development. Again, each spacecraft must evaluate each recommendation and determine applicability.

*Table 2.4.4.1-1 Assembly Phase Recommendations*
Category	Recommendations
Personnel Training	Enforce completion of a mandatory personnel training course for the assembly phase of the program where specific requirements (personnel, operations, cleanroom operations, handling, cleanliness, etc.) are presented.
Selection of Cleanroom	Dependent on sensitivity of spacecraft and components. Generally, most spacecraft assembly occurs in a Class 100,000 or Class 10,000 cleanroom environment. Assembly of optics generally will take place in a better than Class 10,000 environment.
Equipment and Hardware Cleaning	All equipment and hardware introduced into the cleanroom shall be cleaned and verified, prior to entry into the cleanroom (to specific cleanliness levels such as level 100A, 200 A, 300B, etc. per MIL STD 1246).
Prior to Attaching Parts to Other Parts	All mating surfaces (as a minimum) shall be cleaned of molecular and particulate contaminants prior to assembling.
Hardware Inspections	It is recommended that a monitoring and inspection program be implemented during this phase, which includes daily inspection of hardware, for identification of contaminated items. Recleaning of items shall be performed as required. Black light inspections are adequate.
Clean-up of Generated Contamination During Assembly	All debris, filings, lubricants, etc. shall be cleaned up, as it is generated to maintain a clean environment. For example, vacuuming of drilling and riveting sites should be accomplished as they are performed.
Final Assembly of Components	After assembly, all components shall be thoroughly cleaned (per procedures, to prespecified quantitative levels) and verified.
Bagging	Once final cleaning has been accomplished, the parts shall be double bagged (using approved bagging material) and transported or stored in preparation for integration activities.
Certification Logs	Cert logs shall be updated to reflect these activities, and to document the cleanliness level of each part at this point in the build-up.

2.4.5 Spacecraft Integration Phase

Contamination control during the integration phase becomes crucial to the success of the overall mission. Many programs fall short during this phase, without realizing that this is where the strictest of attention to details such as contamination control become all-important.

During spacecraft integration, all systems, subsystems, boxes, solar arrays, etc. are merged together and now constitute the entire spacecraft program. It is especially important to identify the most critical elements (usually the optical and thermal control elements) and to plan integration activities, while keeping in mind the strict contamination requirements of the these crucial systems.

It has been a commonly accepted practice to now consider the entire spacecraft as "contamination sensitive". Usually, the entire spacecraft now "assumes" the contamination sensitivities of the most critical elements, in order to prevent cross-contamination or inadvertent contamination of those critical systems. The spacecraft is generally maintained only in cleanroom environments and bagging and protection of the entire spacecraft is recommended during all downtimes.

2.4.5.1 Integration Phase General Recommendations

The following table reflects some of the more important recommendations for the integration phase of spacecraft development. Keep in mind that more sensitive spacecraft will have much stricter requirements than these, and less sensitive spacecraft may opt to exclude several of these items.

*Table 2.4.5.1-1 Integration Phase Recommendations*
Category	General Recommendations
Personnel Training	Provide mandatory personnel training courses to review the requirements for the spacecraft integration phase.
Cleanroom Selection	Generally, integration of spacecraft will occur in a Class 10,000 cleanroom facility. All the cleanroom operations and controls for this level of cleanroom shall be followed.
Room Monitoring	The cleanroom shall be continually monitored for particle levels; the particle counter shall be equipped with an alarm feature to alert personnel when particle levels are being exceeded. Room recovery plans shall be instituted and implemented when alarms are sounded. Hydrocarbon levels shall be periodically monitored and generally shall be <10ppm. Both particulate and molecular residue fallout plates shall be placed around the room and near the spacecraft critical areas; periodic analysis and evaluation of the witness plates shall be accomplished. Accumulations allowed for the particulate fallout plates (horizontally oriented) should be on the order of "increases of < Level 50 (per MIL STD 1246) per week". Accumulations allowed for the molecular residue witness plates (horizontally oriented) should be on the order of "increases of <0.1 mg/ft2 per week. If witness plate analyses indicate high accumulations of contaminants, all activities shall be ceased in the cleanroom, the spacecraft shall be protected, and steps to identify and eliminate the sources of contaminants shall be performed. Temperature and humidity levels shall be continually monitored.
Special Requirements For Times When Optics Are Exposed	For those times when the critical optics must be exposed to the cleanroom environment, special precautions and protections are generally implemented. These include meeting stricter air cleanliness requirements (e.g. locally Class 100 air), stopping all other cleanroom activities which may generate contaminants, placing witness plates and special monitors near the exposed optics to "collect" (for later analysis) any particles and residue to which the optics may have been exposed.
Cleanroom Operational Requirements	All activities and personnel operations within the cleanroom shall be mandated by a "Cleanroom Operations" document.
Hardware Cleaning and Cleanliness Verification Procedures	A complete set of cleaning procedures (based on type of part or surface) shall be generated and implemented. Surface cleanliness verification procedures (such as Molecular Wash or Rinse Methods, Tape Lift Particle Methods, Optical Scattering Methods) shall be implemented periodically (preferably on a weekly basis), on the actual flight hardware, to assess hardware cleanliness. In cases where flight hardware cannot be tested, a set of "tracking" witness plates shall be placed near the critical components, and shall endure the exact conditions and environments as the flight hardware. These tracking witness paltes shall be periodically tested.
Bagging and Special Protections	Whenever possible, critical components shall remain covered or bagged, within the integration facility. In most cases, it has been shown that the entire spacecraft should be covered during downtimes and weekends, in order to minimize the daily buildup of contamination. All bagging material and special covers shall be cleanroom approved and individually tested for contamination generating potential. Care must be taken whenever bags or covers are removed in order to minimize the risk of "shaking out" contaminants onto the spacecraft during the removal process.
Purging	For most critical optics, full-time (to the greatest extent possible) gaseous nitrogen (highly pure grades) purging is recommended. This type of purging not only keeps humidity levels low near the optics, but also helps to minimize the risk of contaminant ingestion into optical cavities by creating a positive pressure in the cavity. All purge gases (each bottle) should be tested and purities verified prior to use.

2.4.6 Spacecraft Testing Phase

Contamination control during the spacecraft testing phase generally follows a similar set of requirements as set forth above in the integration phase. The goal of the testing phase is to perform the necessary testing without compromising the cleanliness integrity of the spacecraft hardware. It should be noted, here, that there are generally some testing activities which must be accomplished in non-cleanroom environments (e.g. vibration/acoustics testing facilities are typically not cleanrooms). Significant pre-planning, the use of protection devices (covers, bags, etc.), and frequent sampling of cleanliness levels, must be implemented for these testing periods.

In general, the same set of cleanliness requirements which were followed during integration are also fully applicable during testing activities. When in doubt, just follow the same set of requirements as identified in Section 2.4.5.

2.4.6.1 Thermal Vacuum Testing

The importance of the thermal vacuum bakeout and certification phases for space hardware has become a dominant factor in Contamination Engineering planning. Experience has shown that taking the time, at this point in the program development, to fully bakeout and certify each component, assembly, subsystem, etc., has significant pay-offs later during the on-orbit mission phase. Clearly, by reducing the spacecraft outgassing levels in a controlled vacuum chamber during this ground phase, the amount of material left to outgas during on-orbit periods is diminished. For those spacecraft and instruments which are sensitive to even small amounts of molecular contamination, is is important to plan for and cost-out a thorough vacuum bakeout and certification program.

The general philosophy behind vacuum bakeouts and certification of space hardware is as follows:

Commence with bakeouts at the parts level, if possible. Bakeout hardware at the highest temperature possible.
Set quantitative acceptance criteria for each bakeout. These criteria should be based on the total allowable outgassing level for the spacecraft. Usually computer modeling analyses aid in the determination of the allowable outgassing level for hardware. (For some programs, it may be acceptable to "adopt" the outgassing criteria developed for a "similar" spacecraft).
Do not accept hardware which does not meet the acceptance criteria. If a piece or component cannot meet the allowable outgassing criteria, there is a very real reason for it! Take the time, now, prior to further assembly, to outgas as many parts as possible.
As parts become assembled, often, the maximum temperature limits become lower. Bakeouts at lower temperatures are less effective, and take considerably longer to complete.
Develop a detailed Thermal Vacuum Bakeout and Certification Plan for your program. Include the overall plan, schedule, need for instrumentation, and QCM acceptance criteria, as well as a list of the responsible individuals to contact during the test.

Section 3.2.5 of this document discusses the recommended monitoring equipment and certification process for thermal vacuum bakeouts of hardware. The HST program has instituted a thorough vacuum bakeout and certification plan for virtually all flight hardware and has produced numerous vacuum bakeout plan documents which serve as good examples.

2.4.6.2 Testing Phase General Recommendations

There are some adjustments and additional recommendations for ensuring contamination control during such testing as environmental, functional, and vibration. The following table reflects the complete set of general recommendations for the testing phase of spacecraft development. Keep in mind that specific requirements for special types of testing may need to be developed for each individual spacecraft.

*Table 2.4.6.1-1 Testing Phase General Recommendations*
Category	General Recommendations
Personnel Training	Provide mandatory personnel training courses to review the testing plans, monitoring plans, and contamination requirements for the spacecraft.
Testing Facility Selection	Testing facilities should generally meet the same cleanroom requirements as those for the integration phase. All the cleanroom operations and controls for this level of cleanroom shall be followed. Some testing facilities may not be capable of meeting cleanroom requirements. In these cases, the spacecraft should be double bagged prior to entry into the facility, and remain double bagged throughout the test, if possible. For thermal vacuum testing, the vacuum chamber should undergo a chamber bakeout at high temperatures, and then a cleanliness certification (using a QCM), prior to inserting spacecraft hardware. For vibration testing, the facility and vibration fixture must be certified as non-contaminating prior to inserting the spacecraft. As much as practical, the spacecraft should be bagged during vibration testing. As a minimum, critical optics must be protected (covered) during testing.
Facility Monitoring	For thermal vacuum testing, the vacuum chamber must be equipped with QCM monitors to certify the cleanliness of the empty chamber prior to admitting spacecraft hardware and to monitor during the actual thermal vacuum testing. In addition, a cold finger sampling device is recommended. For vibration testing, along with room ambient air cleanliness monitoring, it is necessary to place witness plates under the item being tested, and if possible, mount witness plates at critical surface locations (in a horizontal orientation) to monitor the amount and type of contamination generated during the vibration test. For functional testing and alignment types of testing, monitoring should be accomplished per the integration facility monitoring requirements shown in Section 2.4.5.1.
Special Requirements For Times When Optics Are Exposed	For those times when the critical optics must be exposed to the cleanroom environment, special precautions and protections are generally implemented. These include meeting stricter air cleanliness requirements (e.g. locally Class 100 air), stopping all other testing activities which may generate contaminants, placing witness plates and special monitors near the exposed optics to "collect" (for later analysis) any particles and residue to which the optics may have been exposed.
Testing Documentation	All plans for the testing and the associated contamination control requirements should be documented in a Test Plan document. Special contamination control documents for Thermal Vacuum Bakeouts, Thermal Vacuum/Thermal Balance Testing, Vibration Testing, etc. should be developed. In many cases, it may be possible to insert contamination control sections into existing test documentation. All testing results related to contamination should be documented in a test results report.
Hardware Cleaning and Cleanliness Verification Procedures	Generally, hardware cleaning and verification procedures should follow the recommendations contained in Section 2.4.5.1. It is important to perform pre and post-testing surface cleanliness inspections for all critical surfaces, for each test. Based on these inspections, problems with the hardware and the need for additional post testing cleaning may be identified (for example, identifying that surfaces are rubbing against each other during vibration, or showing after a vacuum testing that high outgassing materials exist). It is recommended that for all testing activities, a set of "tracking" witness plates shall be placed near the critical components, and shall endure the exact conditions and environments as the flight hardware. These tracking witness plates shall be evaluated before and after testing.
Bagging and Special Protections	Whenever possible, critical components shall remain covered or bagged during transport, and within the testing facility. In most cases, it has been shown that the entire spacecraft should be covered during downtimes and weekends, in order to minimize the daily buildup of contamination. All bagging material and special covers shall be cleanroom approved and individually tested for contamination generating potential. Care must be taken whenever bags or covers are removed in order to minimize the risk of "shaking out" contaminants onto the spacecraft during the removal process.
Purging	For most critical optics, full-time (to the greatest extent possible) gaseous nitrogen (highly pure grades) purging is recommended. This type of purging not only keeps humidity levels low near the optics, but also helps to minimize the risk of contaminant ingestion into optical cavities by creating a positive pressure in the cavity. All purge gases (each bottle) should be tested and purities verified prior to use.

2.4.7 Spacecraft Transportation and Storage Phases

During transportation and storage, it is important to preserve the state of cleanliness of the space hardware. Generally this means sufficiently protecting the hardware via covers, containers, bagging, etc. and often means employing a high purity purging of flight hardware.

2.4.7.1 Transportation and Storage Phases General Recommendations

The following table reflects some general recommendations associated with these mission phases.

*Table 2.4.7.1-1 Transportation and Storage Phases Recommendations*
Category	General Recommendation
Hardware Preparation	All hardware shall be assessed and quantitative measurements performed for molecular and particulate levels. The cleanliness status of hardware surface shall be documented. It is generally recommended that at least two levels of protection (e.g. double bagging) be employed around space hardware before inserting it in any storage or transport containers.
Facilities and Enclosures	All transportation and storage facilities, containers, etc. shall meet specific cleanliness requirements. The level of cleanliness is dependent on the criticality of the item, and the level of protection (bags, containers, sealed enclosures, purging,etc.) In general, all transportation and storage facilities shall be cleaned and verified prior to entry of any space hardware. For additional security, it is recommended that the inner bag or enclosure around the spacecraft be purged to create a higher pressure (to minimize ingestion of contaminants into the bag/enclosure) and to lower the humidity levels around the hardware.
Monitoring	It is recommended that periodic monitoring of the transportation/storage environment be accomplished. It is recommended that witness plates be placed inside the bag or enclosure, near critical surfaces, to track along with the hardware and be evaluated for contamination accumulation during these phases. A re-check of cleanliness levels shall be performed at set intervals or at the end of the transport/storage activity. Recleaning shall be performed, as required.

2.4.8 Launch Site Contamination Control

When it comes to launch site contamination control, it is highly recommended, and usually mandatory to prepare a Launch Site Contamination Control Plan (LSCCP).

The goal of a LSCCP is to identify all contamination requirements, all interface requirements, all necessary equipment and supplies needed at the launch site, all necessary personnel requirements, an overall schedule, and a detailed plan of activities for the launch site. This document should be developed by the spacecraft provider, but should be signed off by the responsible launch site representative.

The specific launch site requirements are, naturally, dependent on the type of spacecraft, the type of launch vehicle, the type of companion payloads (if applicable), and which launch site has been chosen. This section has been written to be generic in nature and applies to all situations. Fine-tuning of these requirements is necessary depending on the specific mission parameters.

The launch site phase of a spacecraft program becomes one of the most important and most stressful times for the mission. Problems arise, equipment fails, modifications and repairs must be made, and all of these items must be accomplished in a quick-turn-around mode. Generally, one must consider that anything can happen, and anything can go wrong. The contamination engineer should be prepared to handle these unforeseen issues and problems, and be prepared to fight for solving problems in a competent and acceptable manner. Many times, it has been necessary to obtain second and third opinions from various industry experts in trying to develop a solution to launch site problems. Be prepared for anything.

2.4.8.1 Launch Site General Recommendations

The following table offers a range of recommendations to the spacecraft developer, regarding the implementation of contamination control at the launch site. Keep in mind that detailed requirements may differ according to the specific launch characteristics.

*Table 2.4.8.1-1 Launch Site Recommendations*
Category	General Recommendations
Documentation	It is highly recommended that the contamination engineer obtain "lessons learned" documents from recent spacecraft projects regarding activities at the launch site. It is extremely useful to review what problems have been encountered by recent programs and make plans to solve these events before they become problems again. A mission specific LSCCP shall be written and officially signed off by all participating organizations. It is recommended that necessary supporting documents (personnel procedures, operational procedures, special handling plans, purge specifications, monitoring plans, transport plans, ) be written and signed off well in advance of the arrival of the spacecraft at the launch site. A launch site journal should be developed and updated daily to reflect the day's events and decisions. This journal will be beneficial in helping to solve problems and to aid in compiling the "lessons learned" document at the end of the program.
Launch Site Contamination Control Team	It is essential to assemble a competent, project sanctioned, launch site contamination control team and preferable that team members be the same individuals who have followed the program since the beginning. Any problems or issues arising at the launch site can more efficiently be resolved. Other team members should include the various facility managers, subsystem leaders, and project personnel. The team should meet daily to discuss the day's events, and resolve any problem issues.
Facility Cleanliness	Generally, the cleanliness of launch site facilities is well-known and there should exist a repository of data and historical events summaries for each facility. This will give the contamination engineer a good idea of what to expect. Through the LSCCP process, any special requirements for facilities will have already been addressed. Many times, is may be necessary to build temporary enclosures or institute special precautions in a facility to maintain cleanliness for the current spacecraft. Special covers, bagging, portable cleanrooms, special purge requirements are typically required in many facilities at the launch site. These requirements should be worked out well in advance of arrival of the spacecraft at the site.
Monitoring	Many of the same monitoring principles as mentioned before apply during the launch site process. Facilities at the launch site usually already have in place a basic set of monitoring instruments, such as periodic particle counters and molecular witness plates. Additional monitoring of hydrocarbons, humidity, continuous particle counting, and more complete witness plate programs, may be required. Details should be worked out in advance. It is recommended that a tracking witness plate program be instituted from the arrival of the spacecraft at the launch site, through launch preparation activities, and up to launch. The plates should be analyzed at periodic intervals, and have been very useful in helping to assess the magnitude of unforeseen contamination problems (sandstorms at the launch pad, inadvertent release of gases near the spacecraft). This will not be a wasted effort!
Participation at Launch Site Reviews	Typically, daily project staff meetings are held while the spacecraft is at the launch site. This is a stressful time, and communication and coordination become of paramount importance. The contamination engineer should plan on attending all daily meetings.

2.4.9 Launch Vehicle and Companion Payload Considerations

Typically, the selection of launch vehicle and companion payloads (in the case of Shuttle launches, and some rocket launches), has taken place early in the program and the contamination engineer has little to no input into these decisions.

The contamination engineer must become familiarized with the type of launch vehicle and companion payloads planned by performing these types of activities:

Obtain and review system information regarding the launch vehicle and companion payloads.
Evaluate the mission scenario and timeline.
Identify potential contamination sources; attempt to qualitatively prioritize the magnitude of threat posed by the launch vehicle and companion payload sources:
Fairing and payload bay materials
Fairing and payload bay surface cleanliness levels
Primary engine firings and plumes
Secondary engine firings and plumes
Launch vehicle venting
Launch pad purging
Companion payload materials and venting
Companion payload ejection and orbit insertion (springs, pyrotechnic devices, engine firings, etc.)
Perform modeling analyses (typically during CDR timeframe) to quantify contamination threats.
Develop resolution methods, if required, such as:
Implement a change-out or substitution of specific materials
Improve cleanliness levels of launch vehicle and/or companion payload (such as performing additional vacuum bakeout of components, plan for more rigorous cleaning of surrounding launch vehicle or companion payload surfaces, etc.)
Design protective shields or barriers for your spacecraft or instrument (certainly, one of the most effective and controllable solutions!)
Change ejection and orbit insertion methods

2.4.9.1 Launch Vehicle and Companion Payload General Recommendations

Because so many of these recommendations are based on the specific type of launch vehicle and companion payloads, it is difficult to develop a set of recommendations which may pertain to all situations. But, the following table contains a general set of recommendations based on type of category, which are generally applicable to most spacecraft programs.

*Table 2.4.9.1-1 Launch Vehicle and Companion Payload Recommendations*
Category	General Recommendations
Documentation	Develop interface requirements early in program (CDR timeframe). Perform initial analyses early in program to identify potential problems with launch vehicle and/or companion payload contamination sources. Work with launch vehicle and companion payload organizations to arrive at acceptable solutions. Develop interface agreements with participating organizations.
Launch Vehicle	Evaluate existing documentation and previous analyses to determine which sources pose the biggest threat. Typically, the internal fairing or payload bay cleanliness (surrounding the spacecraft) must be evaluated. NASA has developed a set of choices from which the "user" may select an appropriate cleanliness level (visibly clean, visibly clean Level I, II, and III). Of course, the user must pay for the more rigorous cleaning of the payload bay or fairing surfaces. Perform analyses to quantify contamination deposition and effects during launch and orbit insertion. Identify problems and seek resolution. It may be possible to "negotiate" with the launch vehicle and companion payload representatives parameters such as which payload gets ejected from the payload bay first, what mechanisms or engine firings may be inhibited during operations where critical surfaces may be adversely impacted.
Companion Payload	Get an early start on evaluating the companion payload. It may be possible to make recommendations and negotiate with companion payload organizations regarding materials selection, placement of vents, type of engine firings during proximity operations, etc. It may be necessary to design self-protection devices such as shields and barriers to minimize contaminant transport between payloads during launch.
Cleanliness Levels	A spacecraft with strict surface cleanliness requirements does not want to be launched next to a "dirty" spacecraft or within a "dirty" payload bay enclosure. Often, it has been necessary to "clean-up" launch vehicle and companion payload external surfaces during the prelaunch activities, in order to minimize the possibility of cross-contamination during the launch and orbit insertion timeframes. This is often achieved by performing rigorous exterior cleaning just prior to being inserted into the payload bay or into the payload fairing volume. In many cases, it may be necessary to purge a spacecraft volume until the moment of launch in order to prevent contaminants from depositing on critical spacecraft surfaces.

2.4.10 Launch and Orbit Insertion Mission Phases

There are several parameters associated with the launch and orbit insertion mission phases which may be discussed and adjusted to fit individual spacecraft needs. For example, with a Shuttle launch, it may be possible to inhibit certain Shuttle reaction control engines during spacecraft deployment, and while the spacecraft is within the vicinity of the Shuttle. Or it may be possible to deploy the spacecraft at a preferred attitude or altitude, based on spacecraft desires. All of these types of "fine-tuning" must be negotiated with launch vehicle representatives. Usually, a detailed analysis and justification for these types of adjustments is required, before approval is given.

2.4.10.1 Launch and Orbit Insertion General Recommendations

There are several different aspects associated with launch and orbit insertion which may be either advantageous or detrimental to the contamination environment for the spacecraft. The spacecraft developer must perform analyses to determine optimum arrangements for the launch and orbit insertion mission phases. The types of parameters which may be adjusted include those listed in the following table.

*Table 2.4.10.1-1 Launch and Orbit Insertion Recommendations*
Category	General Recommendations
Cleanliness	The cleanliness of surfaces of the launch vehicle should be selected based on spacecraft contamination requirements. In the case of the Shuttle, special cleaning of the payload bay may be requested, new cargo bay liners may be requested, and special flight monitors may be developed and flown for measuring contamination levels inside the payload bay. In the case of rocket launches where the spacecraft is surrounded by a payload fairing, the cleanliness of the fairing surfaces may be specified, based on spacecraft cleanliness needs. Special purging of payload volumes may also be requested and negotiated.
Venting	Venting scenarios of the launch vehicle and companion payload should be evaluated; problems identified; and resolution scenarios negotiated with the appropriate representatives. Detailed analyses showing the potential problems must be performed in order to justify these requests.
Engine Firings	Engine inhibits and directional requests may be discussed with appropriate launch vehicle representatives. Detailed analyses showing the potential problems must be performed in order to justify these requests.
Deployment Scenarios	All deployment scenarios and backaway maneuvers must be worked out with appropriate launch vehicle personnel.

2.4.11 On-Orbit Through End-of-Life Mission Phases

There are a number of actions which may be taken during the on-orbit through end-of-life mission phases to minimize contamination levels and even to "clean-up" certain surfaces while on-orbit. Careful planning and in some cases, special equipment may be necessary to carry out contamination control measures at this stage of a mission.

For spacecraft which are sensitive to molecular contaminants, all on-orbit sources must be minimized. This may include inhibiting engine firings, redirecting vents and other high outgassing sources.

For instruments which require clear FOV operations, it may be necessary to inhibit certain on-orbit operations during viewing times. Inhibits of vents, mechanisms, solar array movement, engine firings, and any other particle "jostling" activities may be required.

In the case of spacecraft which are sensitive to photopolymerized molecular contaminants, it is recommended that solar exposure be limited. This may mean designing on-orbit maneuvers such that sensitive elements are not exposed to solar illumination, thus minimizing the risk of photopolymerization of contaminants.

The planning for the operations of any aperture doors or covers must be evaluated well in advance of the actual flight. It may be necessary, however, based on actual mission circumstances, to utilize the aperture doors and covers in order to prevent further contamination of critical surfaces.

In the case of lower altitude spacecraft, with surfaces which are vulnerable to the effects of atomic oxygen degradation (erosion), it is recommended that sensitive surfaces never be oriented into the RAM direction. Or if this is impractical, it may be possible to design barriers to "shadow" or protect the vulnerable surfaces from the atomic oxygen environment.

Ironically, the atomic oxygen environment may also serve a beneficial purpose for other surfaces. For example, if a fairly stable surface become contaminated with a molecular residue, it may be possible to deliberately orient the surface in the RAM direction so that it is exposed to atomic oxygen impingement, which usually "erodes" away the contaminant layer, leaving the substrate surface once again clean.

It may also be possible not only to deliberately locate vents in areas of the spacecraft which pose little threat the sensitive elements, but also to design vent barriers or deflectors to deflect venting products (usually considered contaminants) away from sensitive spacecraft elements.

For sensitive missions, it is always advisable to design and fly an accompanying contamination monitor with the spacecraft so that direct measurements of accumulated contamination may be confirmed. Details on types of flight monitors may be found in section 3.2.6 of this document.

Another aspect of this mission phase which is often neglected, is the ability of engineers to evaluate mission performance data (actual optical measurements, temperature data, etc.) and to derive what the effects of contamination might be. For example, if the temperature of a thermal control surface is rising faster than anticipated, it may be because of layer of contamination has deposited on it, and has changed the absorptance properties of the surface, which in turn is causing the surface to heat up faster. Now, knowing this information, it may be possible to take corrective action, such as exposing the surface to atomic oxygen (to "eat away" the contaminant layer) or to modify the thermal system (via computer commands) to rely more heavily on another, uncontaminated thermal component for spacecraft temperature control.

If the spacecraft is demonstrating unexpected responses or seemingly incorrect data, is has often been possible to quickly perform modeling analyses, or perform an experimental investigation to simulate the actual environment (temperatures, solar activity, etc.) being experienced by the spacecraft. Then, is has been possible to verify what is happening, through these ground-based investigations, and help to prevent further degradation, or devise scenarios for correcting or compensating for the on-orbit anomaly.

In recent years, much attention has been paid to the possibility of performing on-orbit cleaning of contaminated surfaces and systems. The most obvious method for achieving this is designing heater systems under sensitive elements (mirrors, lenses, detectors, etc.) which can be turned on to heat-up and "outgas" contaminants from surfaces. This method has already be implemented on a number of spacecraft in the past, including the HST. There are, however, a number of additional techniques being studied to accomplish on-orbit cleaning. These are new technology areas, and a number of techniques have been identified and are in the process of being investigated. Such on-orbit clean-up of surfaces includes:

Exposure of selected surfaces to RAM atomic oxygen environment (accomplished using aperture covers, reticulating arms, or simple positioning of the spacecraft).
More extensive use of clean-up heating devices.
Utilizing CO2 gun cleaning systems, on-orbit, to actually clean-off the contaminants.
Other new technology cleaning techniques, such as laser and plasma cleaning.

2.4.12 Spacecraft Post-Mission and Follow-on Program Phases

It is often during the post-mission analysis of on-orbit performance that the aerospace community learns the most valuable lessons from the mission. Many program improvements, and "lessons learned" have resulted from taking a clear and complete look at what happened during the life of the spacecraft.

In many cases, these lessons learned have been immediately applied to follow-on missions and future projects. For example, during the early Shuttle missions, the atomic oxygen erosion phenomenon was evidenced by examination of the returned Shuttle vehicle. Powdering, and erosion of material thickness was seen, analyzed, and identified. The mechanism of materials erosion was then thoroughly studied, and a host of additional flight experiments were designed and flown. We now know how the erosion works, and what materials are most and least susceptible to the phenomenon. This had aided the aerospace community in better selecting materials for future spacecraft missions, and in some cases, in developing entirely new spacecraft materials.

As another example of learning from previous missions, the aerospace community has been intensely studying the original HST mission and instruments to learn about the effects of UV exposure on contaminated optics (even minimally contaminated optics). It is theorized that even small amounts of UV radiation exposure on thin layers of contaminants will cause photopolymerization. Once photopolymerized, an optical surface becomes somewhat opaque and is not able to measure adequately, particularly in the UV wavelength region. And, unfortunately, because the polymerized contaminant is so tightly fixed to the optical surface, there appears little hope for finding a way to remove the contaminant, on-orbit. The community is also in the midst of studying the possibility that even UV radiation from the Earth s albedo may cause photopolymerization of contaminants on surfaces. Scientists, are, therefore, becoming quite concerned and serious about achieving the lowest possible outgassing levels in and around UV instruments, in an attempt to optimize instrument performance. A variety of preventative and corrective measures have been investigated to determine how to prevent such severe degradation of UV instruments. In this case, follow-on HST UV instruments are being designed with even lower outgassing materials, are undergoing more intensive bakeout programs, are including in-flight contamination monitors, and are planning to incorporate the use of molecular adsorbing material on critical spacecraft components to "collect" and "hold" contaminants before they have a chance to contaminate the critical optics.

3.0 SYSTEMS CONSIDERATIONS

And there’s more...

Along with the afore described "process" guidelines for implementing contamination control engineering, there are a variety of additional systems level topics and more detailed discussions of specific topics which may be helpful to the reader. These topics are discussed in the following subsections.

3.1 Operations in Cleanrooms and Other Controlled Areas

Spacecraft and spacecraft components are manufactured, assembled, tested, and processed in environments intended to control product cleanliness. Cleanrooms are generally assumed to use HEPA or ULPA filters to provide clean air. Other types of controlled areas, sometimes called good housekeeping areas and clean work areas, provide the same function as cleanrooms but do not use HEPA or ULPA filters. The performances of air filters that are used for cleanrooms affect the cleanliness of the air so that lower performance filters allow smaller particles and, frequently, more particles into the area.

One purpose of a cleanroom is to isolate the product from the outside, presumably dirty, environment. The second purpose is to provide an environment in which procedures can be implemented to protect the products from contaminants generated within the cleanroom. For properly operating cleanroom, the people, equipment, and operations within the room are the major sources of contaminants.

3.1.1 Defining Cleanrooms and Other Controlled Areas

Cleanrooms are usually defined by the maximum allowable concentration of airborne particles in the room. Other criteria, such as air temperature and humidity and NVR deposition, may be specified for a cleanroom, but airborne particle concentrations are nearly always used..

FED-STD-209 defines a standard particle size distribution and Classes of air cleanliness. The current version is FED-STD-209E. Table 3.1.1-1 shows the air cleanliness Classes based on FED-STD-209E.

TABLE 3.1.1-1

The Class limits shown above are defined for classification purposes only and do not necessarily represent the size distribution to be found in any particular situation. FED STD 209 also includes the equations used to calculate the number of particles within each size range.

Concentration limits for intermediate Classes can be calculated, approximately, from the following equations:

particles/m³ = 10^M [0.5/d]^2.2

where M is the numerical designation of the Class based on SI units, and d is the particle size in micrometers, or

particles/ft³ = N_C [0.5/d]^2.2

where N_C is the numerical designation of the Class based on U.S. Customary Units, and d is the particle size in micrometers.

The air cleanliness Classes must be specified at one size range, but additional size ranges can be specified. For space systems, two size ranges are usually specified. For classes 1,000 and greater, the two sizes are usually ³ 0.5 µm and ³5 µm. For class 100, 0.3 and 0.5 should be used because there are not enough particles in the 5 µm size range to get an accurate count.

Sometimes different classes are specified at different size ranges. For example, Air Force TO 00-25-203 defines a Controlled Area (Class 300 000) with 300 000 particles per ft3 equal to and larger than 0.5 µm and 700 particles per ft3 equal to and larger than 5.0 µm. This would be specified as Class M 7 at 0.5 µm (Class 283,000) and Class M 6.5 at 5.0 µm (Class 100,000) using FED-STD-209E. An example of this type of cleanroom is the High Bay in the Operations and Checkout building at the NASA KSC. Because the HVAC system does not have HEPA filters, particles in the size range of 0.3 m to 5 µm may get into the room from the outside air. Therefore, higher particle concentrations must be allowed for this size range.

One discrepancy can be found in FED-STD-209E. Many of the particle concentrations in Table 3.1.1-1 do not match the concentrations calculated by using the equations at the bottom of Table 3.1.1-1. This occurred because the particle concentrations from Table I of FED-STD-209D were retained in FED-STD-209E and the exponent (2.2) in the equation was rounded to one decimal place. The result is that when the equation is used to calculate intermediate concentrations, as allowed in the standard, there are discontinuities with the numbers carried over from FED-STD-209D. The 1 µm and larger size range in Table 3.1.1-1 is not in Table I from FED-STD-209E. In Table 3.1.1-1, the 1 µm and larger concentrations were calculated using the equation.

The above problem with FED-STD-209E becomes moot with the adoption of the proposed ISO standard, CD 14644-1. FED-STD-209 is expected to be canceled as the U.S. government continues its efforts to eliminate government standards and adopts non-governmental standards. The transition may present problems as many existing contracts and instrumentation use FED-STD-209.

Table 3.1.1-2 shows the airborne particle concentrations from the proposed ISO standard. As can be seen in Table 3.1.1-2, the equation differs from the one in FED-STD-209E. The exponent is 2.08 instead of 2.2, and the base particle size is 0.1 µm instead of 0.5 µm. This was designed to provide particle concentrations at 0.5 µm essentially equal to the concentrations in FED-STD-209E for integer values of ISO N. For example, ISO 5 is equal to Class 100 (FED-STD-209E, 100 particles/ft³) at 0.5 µm, and ISO 8 is nearly equal to Class 100,000 (99,600 particles per ft³) at 0.5 µm. However, at 5 m the difference is greater (828 vs 700). The approximate FED-STD-209E Classes are not included and are not a part of ISO CD 14644-1 but are included in Table 3.1.1-2 for comparison purposes only.

TABLE 3.1.1-2

The Class limits shown above are defined for classification purposes only and do not necessarily represent the size distribution to be found in any particular situation.

C_n = 10^N[0.1/D]^2.08

where: C_n represents the maximum permitted concentrations (in particles/m³ of air) of airborne particles that are equal to or larger than the considered particle size. C_n is rounded to the nearest whole number with no more than three significant figures. N is the ISO classification number,which shall not exceed a value of 9. Intermediate ISO classification numbers may be specified, with 0.1 the smallest permitted increment of N. D is the considered particle size in micrometers. 0.1 is a constant with a dimension of µm.

(Note: To convert to USCS (particles/ft³), multiply C_n by 35.31466 or divide by 2.831685x10^-2)

Although the differences between the two tables appear to be large, the importance is minimal because the uncertainties in the measurement of airborne particle concentrations are also large.

Another aspect in defining airborne particle concentrations is the operational state of the cleanroom. There are three operational states defined in FED-STD-209E (and in ISO CD 14644-1). When airborne particle concentrations are specified, the operational state must also be specified. The three operational states are as follows:

· 1. As-built-A cleanroom that is complete and ready for operation, with all services connected and functional, but without equipment or operating personnel in the cleanroom.

· 2. At-rest- A cleanroom that is complete, with all services functioning and with equipment installed and operable or operating, as specified, but without operating personnel in the cleanroom.

· 3. Operational- A cleanroom in normal operation, with all services functioning and with equipment and personnel, if applicable, present and performing their normal work functions in the cleanroom.

It should be noted that the as-built state is typically used for new cleanroom construction or modifications as a basis for certifying contractual performance.

The at-rest state is typically used to describe the baseline conditions in the cleanroom. This is useful for monitoring cleanroom and HVAC performance and long-term trends in performance. In the at-rest state, the airborne particle concentrations will tend to approach the particle concentrations in the inlet air. For HEPA filtered air, this will be Class M 3.5 (Class 100) or cleaner.

The operational state is used describe the maximum allowable airborne particle concentrations for processing products. When specifying or designing a cleanroom system, the required particle concentrations for the operational state should be specified.

Other environmental factors (such as temperature, humidity, airborne gases and vapors, and particle and NVR deposition) should be handled in a similar manner.

3.1.2 Determining Cleanroom Design and Operational Requirements

There are a number of documents to review which aid in defining proper cleanroom design and operational requirements, including:

· AF T.O. 00-25-203, Contamination Control of Aerospace Facilities

· IES-RP-CC012.1, Considerations in Cleanroom Design

· IES-RP-CC018.2, Cleanroom Housekeeping - Operating and Monitoring Procedures

· IES-RP-CC026, Cleanroom Operations

Because the purpose of a cleanroom is to protect the product from contaminants, the determination of cleanroom requirements is based on product cleanliness requirements. As stated above, requirements should be based on the operational state of the cleanroom.

The airborne particle concentration requirements can be estimated using the methods proposed by O. Hamberg and is documented in various publications. Hamberg assumed that the airborne particle concentrations in the cleanroom have a size distribution as described by FED-STD-209 and that the distribution does not change with time even as the concentration changes. This is not necessarily true, but allows the use of a simple model when the true distributions are not usually known or can be predicted.

Using a 24 hour average for airborne particle concentrations in a cleanroom, Hamberg calculated the quantities and size distributions for particle depositions on surfaces. The resulting size distributions are similar to actual distributions measured in operational cleanrooms.

Based on product particulate cleanliness requirements and the exposure times in the cleanroom environment, the Hamberg model will provide a maximum, allowable, average airborne particle cleanliness Class, per day, that should be specified.

The Hamberg model implies one more assumption: reasonable procedures are followed to control particles generated within the cleanroom by equipment and personnel.

The types of procedures that are reasonable depend upon the level of product cleanliness that is required, the types of airflow in the room (unidirectional or nonunidirectional, vertical or horizontal flow) and air flow rates or velocities.

More demanding product cleanliness requirements lead to unidirectional airflow and higher air flow rates when designing a cleanroom and more stringent operating procedures.

3.1.3 Cleanroom Garments

Some documents relate garment requirements to the Class of cleanroom. The Class of cleanroom is based on product cleanliness requirements, as discussed above, but the garment requirements also depend on product cleanliness requirements and operations in the cleanroom; so, the relationship between garment requirements and cleanroom Class is indirect. Typically, the more stringent the product cleanliness requirement, the smaller will be the required airborne particle Class and the more demanding is the garment design.

The purpose of the cleanroom garment is to prevent particles generated by people from getting to the product. The perfect garment is made of low particle generating materials and isolates the wearer in a sealed, contained unit with a breathing air supply. Although such garments are used in the electronics and biomedical industries, they are cumbersome to wear, are expensive, and are not necessary for most aerospace applications. An exception might be interplanetary spacecraft that must be protected from biological contaminants.

The usual garment choices for aerospace use include a full coverall ( bunny suit ) with a hood and high top shoe covers ( boots ) or a frock (smock) and partial head cover with some type of shoe cover.

The smock does not contain the particles generated by the wearer of the garment because the bottom is open. Studies have shown that airborne particle concentrations increase when frocks are worn as compared to coveralls. Also, the open bottom allows large particles and debris to fall out. These will not become airborne but will deposit on the cleanroom floor or on product surfaces near the wearer.

Frocks are not recommended when personnel are working above hardware or when product cleanliness levels are stringent. Frocks are suitable for processing hardware in clean benches where coveralls are not needed.

General requirements for cleanroom garments include the control of ESD, high permeability for air and water vapor, low transmission of particles, low particle generation, cleanability, good wear properties, including resistance to laundering and dry cleaning, as appropriate.

IES-RP-CC003.2 is a general recommended practice for cleanroom garments, and ASTM E 1549M is a specification for two types of coveralls used in aerospace cleanrooms. One type uses a fabric constructed of monofilament, polyester fiber containing a grid of coated carbon fibers to reduce the probability of ESD.

Another type, described as for hazardous operations, is designed to resist flame. It uses a fabric constructed of monofilament, Nomex fiber with a grid of coated carbon filament.

Both fabrics will meet the requirements of Class 1 of NFPA 7702-1980 which means that they are self-extinguishing when the ignition source is removed. However, the polyester fabric can melt when exposed to high heat fluxes. The Nomex fabric will provide extra protection to the wearer when exposed to flame. Nearly all aerospace applications use the polyester fabric.

In order to meet ESD requirements, personnel should be grounded using appropriate methods such as wrist or leg straps.

Other components of the garment system, such as shoe covers, hoods, caps, and gloves should be selected with the same care as the coverall or frock considering the hardware cleanliness and operational requirements.

3.1.4 Equipment and Materials

Equipment and materials used in cleanrooms should be cleanable, have low particle generation properties, and have low outgassing or leaking of condensable and volatile species that can affect the performance of the hardware. Metals that can corrode in the cleanroom environment and produce soft or loose oxides should not be used. Corrosion resistant steel and hard anodized aluminum are usually suitable.

Polymeric materials are suitable provided that they do not outgas contaminants and do not deteriorate to produce particles. Outgassing can be determined using ASTM E 595 and F 1227, the standard screening tests for outgassing.

E 595 was designed to compare spacecraft materials; so, the material test temperature of 125O C can be too high for materials designed for use at room temperatures. Frequently, the E 595 test method is modified to use a lower temperature, such as 60O C, to screen materials for use in cleanrooms.

Often coatings must be used on products brought into cleanrooms. It is generally not advisable to use paints because of chipping and flaking resulting from poor adhesion or the brittle characteristics of the coating. However, low outgassing urethane and baked-on coatings have proven to be satisfactory.

Wood is not recommended; however, some wood products with acceptable coatings have been used.

Paper is a particular problem. Low particle generating paper (cleanroom paper) is frequently used. IES-RP-CC020.2 describes substrates and forms for use in cleanrooms.

Many standard paper items are available on cleanroom paper. However, cleanroom paper is expensive and may not be readily available during spacecraft operations. Paper items, such as procedures required during operations, may be enclosed in a suitable plastic film, such as polyethylene, and used near the hardware.

For materials that can not be enclosed in suitable films, procedures may be used to prevent them from contaminating hardware. The general guidelines are to keep them far from and down wind of the hardware. This latter guideline may be difficult in a nonunidirectional airflow room where turbulence can carry particles in many directions.

3.2 Contamination Monitoring Methods

The monitoring of contamination levels is one of the most essential elements of Contamination Engineering! The following sections provide details on the currently employed methods and practices for contamination monitoring. The reader is invited to consult the bibliographical section of this document (4.2 Related Works) for a complete listing of standards and procedures used for contamination monitoring.

3.2.1 Overview

The general purposes for monitoring contamination during manufacturing, testing and ground processing are for the determination of environmental conditions to which the hardware is exposed and the cleanliness of the product. Four objectives can be stated to describe the contamination monitoring. These are the following: early warning of problems, verification of requirements, failure analysis and damage assessment, and historical data.

Details on the requirements for these four monitoring objectives are noted below:

1. Early Warning of Problems

The general requirement is to measure changes in critical environments that can affect the performance of the systems being processed. Monitoring for early warning has the following basic requirements:

· High sensitivity so that changes can be detected before contaminant levels approach requirement levels.

· Real time display and alarm are needed so that personnel are aware of possible problems.

· Data should be recorded in a form that is readily available for inspection and analysis.

· High reliability is required to minimize false alarms and system down time.

· Safe operation in hazardous environments is necessary for launch site monitoring.

· There shall be no hazards to spacecraft, payloads, and launch vehicles

· .Low labor expenditure is required to minimize operational costs.

2. Verification of Requirements

Requirements for the environment and surface cleanliness need to be verified in accordance with the program documentation such as the statement of work, contamination control plan, and interface requirements. The detailed requirements follow:

· Quantitative outputs are needed based on the quantitative requirements in the program documentation.

· Fast turnaround of data is needed so that operations are not delayed.

· Accuracy and sensitivity should be commensurate with the requirements.

· Standard procedures are preferred so that data can be compared with previous measurements and used for future systems.

3. Failure Analysis and Damage Assessment

Although efforts are made to avoid failures and accidents, it is important to be prepared so that data are available to determine the causes and to assist in developing corrective actions. The following requirements apply to this monitoring objective:

· Quantitative data along with subjective evaluations are needed.

· Accuracies and sensitivities of measurements commensurate with program requirements are required.

· Data from early warning and verification methods may be applied to the failure analysis and damage assessment as well as using additional laboratory methods.

4. History

A good historical data base is useful for analyzing the performance of spacecraft, payloads, and facilities. The sources of this data include the information gathered to meet the above monitoring objectives. An electronic data base that is easy to access and search is desirable. Long term trend data show changes that can not easily be observed in the short term.

There are a wide variety of methods, techniques, and devices used to monitor and measure molecular and particulate contamination. New and better methods are continually being developed. Both active and passive methods are used and include surface and volumetric measurements. Active methods are those that use sensors that have an electronic output or, as a minimum, a visual display. Passive methods are usually witness surfaces or sampling techniques that require analyses of the sample in the laboratory after removal from the sampling location. Surface measurements are intended to determine the levels of contaminants on hardware or on witness or sensor surfaces in the cleanroom. Volumetric measurements include contaminants in the air or other fluids used in the processing of spacecraft.

Good sources for obtaining the industry-wide accepted measurement practices and test methods include the ASTM (which holds frequent meetings and is continuously reviewing and updating the official standards), the Institute of Environmental Sciences (IES), military standards, NASA documents, and other industry groups. The ASTM, Institute of Environmental Sciences, and other standards organizations have various committees in charge of the official standards and procedure documents. These standards are available from the organizations and should be available at any technical library. For a listing of the more commonly used documents produced by these organizations, please refer to Section 4.3.

The following sections are intended to provide a general overview of the most widely used contamination monitoring methods and equipment.

3.2.2 Environmental Monitoring

Environmental monitoring pertains to the measurement of contaminants and other environmental factors within cleanrooms or cleanroom-type facilities. There are many parameters which must be monitored within a cleanroom (temperature, humidity, pressure, etc.). Although these are not necessarily contaminants, they do affect the contaminant deposition on spacecraft systems and are often critical in determining the performance of the cleanroom system.

Automated collection and processing of environmental data is critical to meeting requirements for early warning and verification of environmental requirements.

The measurement of airborne particle concentrations, airborne molecular contaminants (gases and vapors), NVR deposition, particle deposition, air temperature and relative humidity, and air pressures within and pressure differentials between locations are typical of automated environmental measurements which should be incorporated into the cleanroom routine.

Passive sample plates are also used to monitor the environment. These do not provide real time data but a variety of analyses are performed in the laboratory following exposure in order to determine the type and amount of contaminants collected, over time, in a particular cleanroom or cleanroom location.

The following subsection provide details on molecular and particulate environmental monitoring in cleanrooms or cleanroom-type facilities.

3.2.2.1 Molecular Environmental Monitoring

The monitoring of molecular contaminants within a cleanroom or cleanroom-type facility involves the measurement of airborne molecular contaminants, and the measurement of molecular "fallout" or deposition on surfaces within the cleanroom.

3.2.2.1.1 Airborne Molecular Monitoring Airborne molecular contaminants are typically measured within cleanroom facilities to monitor levels of hydrocarbons and other species. Some techniques in use are noted below:

· Air samples are collected using an evacuated container, which is usually a 39 L metal bottle ( melon bottle ). Samples are taken to the laboratory and measured using a flame ionization detector calibrated with methane; also, the measurements are reported in ppm. methane equivalent. GC/MS (gas chromatography/mass spectrometry) can be used to determine the composition of the sample. The disadvantage of this method is that contaminants can exceed requirements between the periodic measurements without detection.

· FIDs (flame ionization detectors) and PIDs (photoionization detectors) have been used in cleanrooms for both periodic and continuous measurements. FIDs present a potential hazard in cleanrooms where propellants are present. As with FIDs, PIDs require calibration with a reference gas and do not identify the composition of contaminants. Because PIDs can not detect methane, a higher molecular weight calibration gas must be used.

· A recent development at NASA KSC is the FTIR Air Sampler. This instrument samples the air continuously and by using a long optical path length can detect molecular species using IR spectroscopy. The instrument can monitor one wavelength or scan through a number of wavelengths. The data can provide both quantitative (ppm) and qualitative (composition). The electronic output is capable of being connected to the active environmental monitoring systems in use in many cleanrooms.

3.2.2.1.2 Surface Molecular Monitoring

It is vitally important to measure and identify the surface accumulation of molecular contaminants within cleanroom environments since, it may be assumed that these same contaminants will probably also be found on any space hardware located within the cleanroom.

Generally, within cleanrooms, molecular monitoring is accomplished via a witness plate program where stainless steel plates or in some cases, glass slides or mirrors, are placed throughout the cleanroom (usually at the locations of critical space hardware), and are allowed to accumulate contaminants for a preset period of time (e.g. 1 week). The exposure time should be based on the precision of the witness plate technique and the NVR deposition requirement. A high precision (high sensitivity) technique requires a shorter exposure to get a measurable deposit. For example, ASTM E 1235M has a precision of between 0.1 and 0.2 mg/0.1m2. At the end of the time period, the plated (or optical sampled) are carefully covered so that contaminants are not disturbed, and transported to a laboratory area where quantitative and qualitative measurements may be taken. In a thoroughly managed witness plate program, several witness plates are laid out next to each other, and just one is removed at a time, while the others are allowed to continue accumulating. At some point, all the plates are eventually measured, and comparisons, verifications, and cross-checks of data may be accomplished. In the case of witness plates, generally a molecular wash method is employed to gather the accumulated contaminants into a beaker and then a solvent evaporation technique is performed to measure the quantity of contaminants per unit area ( g/cm2, mg/0.1m2, or mg/ft2). In many cases, it is desirable to further analyze the removed contaminants to determine the chemical composition of the contaminants (which aids in identifying the contaminant source within the cleanroom). The primary methods used for chemical analysis of these types of contaminants are gas chromatography, infrared spectrophotometry, and/or mass spectrometry. Some methods for measuring NVR deposition using witness plates are shown below.

· ASTM E 1234M, Standard Practice for Handling, Transporting, and Installing Non-Volatile Residue (NVR) Sample Plates used in Environmentally Controlled Areas for Spacecraft, 1995.

· ASTM E 1235M, Standard Test Method for Gravimetric Determination of Non-Volatile Residue (NVR) in Environmentally Controlled Areas for Spacecraft, 1995.

Another method involves performing pre-exposure characterization of an IR plate and then exposing the plate in the cleanroom for a period of time. The IR plate is then taken back to a laboratory where post-exposure optical measurements may be performed. The plate may be an internal reflectance crystal or mirror that is measured using infrared spectroscopy. FTIR (fourier transform infrared spectroscopy) is preferred because of its high sensitivity. The measurement provides information on the composition of the deposit. Quantitative information can be obtained if the technique is calibrated using known quantities of expected NVR materials. Typical NVR deposits consist of hydrocarbons, esters, and silicones.

TQCMs have also been used to provide active, real time measurements of NVR deposition in cleanrooms.

Recently, a new type of ultra-sensitive monitoring device, the Surface Acoustic Wave (SAW) measuring device, has been used within cleanrooms to monitor the build-up of contaminants. The SAW is able to detect and measure even small amounts of accretion (3 x 10 -12 g/cm2). The stability and accuracy of the SAW device is now under evaluation at GSFC and KSC in cleanrooms.

3.2.2.2 Particulate Environmental Monitoring

Both airborne particulate monitoring and particle fallout monitoring are important in cleanrooms and cleanroom-type environments. The following sections provide details on these categories.

(1)Airborne Particle Monitoring

The monitoring of airborne particles within cleanrooms is an essential element of contamination control. Particulate sampling involves determining the number and size of particles in a specific volume of air. Discrete particle counter (DPC) devices based on light scattering are standard equipment for all cleanrooms. For state-of-the art cleanrooms, these instruments are part of an automated monitoring system. The sample volume of air is pumped through a capillary sensing chamber where a beam of light illuminates an individual particle. Measurements of light scattered off the particle provides information on the optical size of the particle. The numbers and sizes of particles are collected and stored in the instrument memory. Results are displayed in terms of particles per unit volume of air in selected size ranges.

FED-STD-209E defines airborne particle concentrations per cubic meter (cubic foot) of air. Typical aerospace cleanrooms are monitored in two size ranges: 0.5 µm and µ5 m. See Section 3.1.1 for additional information.

Because most light scatter DPCs are limited to particle sizes less than 20 to 30 m, larger particles are collected by pumping air through filters and then counting the particles on the filters. However, larger particle have a lower probability for remaining airborne and tend to fallout near to the sources of the particles. Some test methods are noted below:

· ASTM F 25, Standard Test Method for Sizing and Counting Airborne Particulate Contamination in Cleanrooms and other Dust Controlled Areas Designed for Electronics and Similar Applications, 1968. (This method collects particles on filters.)

· ASTM F 50, Practice for Continuous Sizing and Counting of Airborne Particles in Dust Controlled Areas and Cleanrooms Using Instruments Capable of Detecting Single Sub-Micrometre and Larger Particles, 1992.

3.2.2.2.2 Particle Fallout Monitoring

Particle deposition has usually been monitored using witness plates placed in the cleanroom. Recently, methods for real time, continuous monitoring of particle fallout has been performed using a variety of instruments, and additional techniques are continuing to be studied.

Some of the commonly used methods for measuring particle fallout are noted below:

· 37 mm diameter gridded filter plates are exposed in the cleanroom and returned to the laboratory for manual counting. The surface area is small; so, the statistical sample is poor. Also, test have shown that errors are large because of the tedious procedure of manual counting using a microscope.

· Automated counting using laser scanning instruments is being used. At KSC, a laser scanning instrument, manufactured by ESTEK, counts and sizes particles on witness surfaces, usually silicon wafers or metal Winchester disks. The precision is high, but correlation with other particle counting techniques is still in progress. As with airborne optical scatter methods, the particle size is an optical size based on standard particles, usually calibrated polystyrene spheres.

· A particle flux monitor using light scatter techniques was developed by High Yield Technology. It is capable of measuring particles up an optical size of 250 m. It can also be used to sample large airborne particles by pumping known quantities of air through the sensor.

· NASA KSC has developed a continuous, real time , monitor that measures light scattered from particles on a mirror collector. The precision is good, but the instrument does not count and size individual particles. However, this may not be a problem because light scatter measurements correlate well with optical performance, and requirements can be specified in terms of light scatter and PAC (percent area covered). See MIL-STD-1246C for more details.

3.2.3 Hardware Surface Monitoring

Determining the type and amount of contamination on hardware surfaces is an important component of any contamination control program. A hardware monitoring plan should be developed early in the program and implemented throughout all program phases. Typically, hardware should be tested on a weekly basis, for both molecular and particulate contaminants. In addition, witness plate programs are commonly instituted for cleanrooms, especially when it is difficult to take measurements on actual space hardware surfaces.

The project contamination engineer is responsible for assuring that these measurements are performed and for evaluating the results, and then for making decisions regarding the need for cleaning. Based on the monitoring results, the contamination engineer will also evaluate the need for removing certain materials from the cleanroom, or for disallowing certain cleanroom activities to prevent further build-up of contamination.

Many of the same techniques which were discussed in Section 3.2.2, are also applicable to hardware surface monitoring.

3.2.3.1 Measurement of Molecular Contaminants

Surface measurements of molecular contamination usually include performing a solvent rinse or solvent wipe (using a proper procedure), collecting the solvent and residue, evaporating away the solvent and then measuring the residue. Further chemical analysis is then usually performed to ascertain the exact type of contaminants. Other methods involving optical measurements such as reflectance properties may also be utilized. Often, for very sensitive optics, or for surfaces which are unreachable (for performing the solvent rinses), a witness plate tracking program will be used. Measurements will be made on the witness plates and it is then assumed that those measurements are the same as the actual hardware surfaces.

Please refer back to Section 3.2.2.2 for details on the measurement of NVR, etc. on surfaces. The same techniques apply to performing direct measurements on space hardware surfaces. Although, it must be stressed that space flight hardware is considerably more complex than a bare witness plate. The appropriate systems and subsystems engineers must approve any cleaning and monitoring of flight hardware.

In many cases, it may be unadvisable to perform solvent wipes, washes, etc. directly on flight hardware. For these cases, an accompanying witness plate should be placed near the critical surfaces of interest, and periodic measurements of the witness plates should be taken. The results of these measurements are considered indicative of actual flight hardware cleanliness levels.

Along with the above-mentioned techniques, surface molecular contaminants can also be detected using wetting techniques that detect FID of some contaminants. See the following specifications for details:

· ASTM F 21, Method for Hydrophobic Surface Films by the Atomizer Test, 1965.

· ASTM F 22, Method for Hydrophobic Surface Films by the Water-Break Test, 1965.

3.2.3.2 Measurement of Particulate Contaminants

Particulate contamination on surfaces is commonly measured using a tape lift method. A low residue tape is placed on the surface to be measured, using a procedure which stipulates the amount of pressure to apply, and then removed and analyzed using a microscope or an image analyzer. The number and size of particles are determined, and the results are may be translated into a particle distribution and subsequently, an equivalent MIL-STD-1246C cleanliness level, PAC, or other specified requirement. Removable, small area hardware pieces may also be measured directly using a microscope or image analyzer. As with the molecular measurements, for surfaces which cannot safely be measured using the tape lift method, a witness plate tracking program may be implemented.

Visual inspection is also used to determine cleanliness of hardware. NASA SN-C-0005C specifies visually clean criteria and inspection methods for STS Orbiter and payloads. The determination of quantitative cleanliness levels is difficult using visual inspection because color of surfaces and particles (contrast) and surface roughness affect the ability to see particles on surfaces. Using calibrated, standard reference surfaces, it is possible to compare unknown, similar surfaces and approach quantitative results. The eye is very sensitive; so, it is possible to see very low levels of contamination on some surfaces. The eye can resolve particles of sizes down to 100 to 60 m under good viewing conditions. When viewing good optical surfaces in the dark with off axis illumination, the eye can detect smaller particles but cannot resolve the size. The following specifications may be used when performing visual surface particle measurements:

· ASTM F 24, Method for Measuring and Counting Particulate Contamination on Surfaces, 1965.

· ASTM F 51, Method for Sizing and Counting Particulate Contamination in and on Cleanroom Garments, 1989.

3.2.4 Fluid and Purge Gas System Monitoring

Fluids, such as nitrogen, helium, compressed air, propellants, and solvents, must also meet cleanliness requirements. Some methods are noted below:

· ASTM F 301, Practice for Open Bottle Tap Sampling of Liquid Streams, 1991.

· ASTM F 302, Practice for Field Sampling of Aerospace Fluids in Containers, 1989.

· ASTM F 303, Practices for Sampling Aerospace Fluids from Components, 1978.

· ASTM F 306, Practice for Sampling Particulates from Man-Accessible Storage Vessels for Aerospace Fluids by Vacuum Entrainment Technique (General Method), 1970.

· ASTM F 307, Practice for Sampling Pressurized Gas for Gas Analysis, 1988.

· ASTM 309, Practice for Liquid Sampling Noncryogenic Aerospace Propellants, 1970.

· ASTM 310, Practice for Sampling Cryogenic Aerospace Fluids, 1970.

· ASTM F 311, Practice for Processing Aerospace Liquid Samples for Particulate Contamination Analysis Using Membrane Filters, 1983.

· ASTM F 327, Practice for Sampling Gas Blowdown Systems and Components for Particulate Contamination by Automatic Particle Monitor Method, 1978.

· MIL--STD-1201C , Ethyl Alcohol (Ethanol), Technical and Denatured Grades (Proposed for cancellation).

· MIL-P-27401C, Propellant Pressurizing Agent, Nitrogen, 20 Jan. 1975.

· MIL-P-27407A, Propellant Pressurizing Agent, Helium, 28 Nov. 1978.

· KSC-C-123F, Specification for Surface Cleanliness of Fluid Systems, 19 Oct. 1979.

· KSC-C-182, Gas Cleanliness Requirements for Operational Gaseous Nitrogen, Helium, and Hydrogen Systems at Complex 39.

3.2.5 Thermal Vacuum Outgassing Monitoring

This section shall deal with the recommendations for contamination-related monitoring of the thermal vacuum test operations. Of course, the standard thermal and pressure monitors are always required during these tests.

A quantitative measurement of outgassing levels during thermal vacuum bakeout and certification testing is a critical aspect of Contamination Engineering. It is important to know the amount of outgassing emanating from the test hardware, in order to fully assess the on-orbit contamination potential and subsequent impacts to spacecraft performance. Often, the results of the thermal vacuum testing are incorporated into detailed analytical models in order to calculate predictions expected contamination levels. Precise measurements are required and the Quartz Crystal Microbalance (QCM) is generally utilized to acquire these data. QCMs are used during testing to measure the rates at which material accumulates. QCMs are temperature controlled and often a cryogenic QCM (CQCM) is implemented so that the accumulation surface can be set at very low temperatures.

In addition, it is extremely useful to incorporate an RGA system into the thermal vacuum testing. An RGA will yield information on the chemical types and relative concentrations of contamination being outgassed in the chamber. With this information, the Contamination Engineer may be able to identify which material or component is producing the major contaminants, and over time, will be able to evaluate the relative reductions of the major contaminants.

A well-organized thermal-vacuum testing program consists of a preparation phase, a bakeout phase and then a certification phase. Each of these phases, and the associated recommendations is summarized in the following table.

Table 3.2.5-1 Contamination Monitoring Recommendations for Thermal Vacuum Testing
Type of Thermal Vacuum Test Phase Recommendations
Preparation	· It is recommended that the empty chamber, monitoring equipment, chamber cables, fixtures, etc., as well as the flight hardware being tested, undergo a thorough cleaning and surface cleanliness certification (to remove both particles and molecular contaminants) prior to commencement of any test activities. · QCMs should be located in positions which are representative of a critical surface location, or which have the largest field- of- view of the hardware undergoing testing. · Latest experience with this type of testing is resulting in the recommendation that a bakeout "box" be built and utilized for virtually all flight hardware bakeouts. Details on how to perform testing using the box may be found in a project document such as the HST Vacuum Certification Plan for the ASIPE. · Along with the QCMs, a cold finger (and possibly a cold plate) and the RGA sampling port should be installed in the chamber, at appropriate locations. · If particle contamination is a major concern, placement of witness plates (fallout plates) under critical hardware is recommended. · The test chamber, monitoring equipment, chamber cables, and fixtures should undergo an empty chamber bakeout and certification prior to installing any flight hardware. The purpose of the empty chamber bakeout and certification is to "clean-up" the chamber and to quantify the outgassing contribution emanating from the chamber and test equipment. In this manner, it will be possible to subtract these amounts from the overall testing results when the hardware is installed.
Bakeout Phase	· The goal of the bakeout phase is to deplete the molecular contamination from the nonmetallic materials used in/on the flight hardware · Bakeout temperatures should be maximized (without jeopardizing the hardware) in order to shorten bakeout times. Each piece of hardware should be evaluated to determine the maximum tolerable bakeout temperature and each responsible subsystem engineer should sign-off on the bakeout plan. · A QCM requirement should be set, in advance of the bakeout, specifying the rate to be achieved before ending the bakeout, and then continuing on to the certification phase. This requirement should be based on analytical modeling results. · In practice, the bakeout should be continued until no significant benefit can be derived from further bakeout. In practice, this means evaluating the QCM data during the bakeout, and when the change in the change ( ) of the QCM reading is low (on the order of <3%), then, it is clear that continued bakeout will probably not significantly improve the numbers. A typical QCM requirement is on the order of "<3 Hz/hr/hr". Once this value is achieved, the bakeout phase may end and the certification phase may commence. · If the values are significantly higher than the 3% goal, the test engineer has three options: · Continue baking at current temperature, for as long as time permits, or · Check with subsystem engineers as to the acceptability of increasing the bakeout temperature; if allowed, proceed with higher temperature bakeout, or · Move into the certification phase (lowering temperatures of the test item) and check on QCM readings to see if the certification phase QCM requirement is achieved. · RGA data should be consulted to evaluate the sources and concentrations of outgassed contaminants.
Certification Phase	· Once the bakeout criteria has been reached, the certification phase may begin. · For the certification phase, the general rule of thumb for temperature assignments is as follows: · Test item temperature should be set at 10C above the maximum hot case operating temperature for the item · QCM temperature should be set at 10C below the lowest cold case temperature for the most critical surface · Once these temperatures are reached, the QCM data should be evaluated. · The certification phase QCM acceptance criteria is usually based on analytical modeling results. Typically, for high sensitivity spacecraft, this criteria is on the order of "<1 Hz/hr, for 8 consecutive hours". · The cold finger should be operated during these last 8 hours of the test to accumulate contaminants for post-test analysis. · If the QCM values are too high, this usually means that additional bakeout is required; the test should move back to the bakeout phase, and then start the certification later, after the additional bakeout has been completed. · After completion of the certification phase, the chamber and test items should be brought back to ambient pressure and temperature. The cold finger and/or cold plate should be kept at cold temperatures during this process. Immediate removal and analysis of these items should be performed once the chamber is opened. · The RGA data should be evaluated to determine if concentrations and types of contaminants are acceptable.

A complete thermal vacuum bakeout and certification test report should be compiled and submitted to the project management for review and approval.

3.2.6 Flight Contamination Monitors

Flight Contamination monitors are highly recommended, especially for those programs with high contamination sensitivity. In truth, they provide the only method for knowing exactly what levels of contamination are actually being encountered by the spacecraft, after the launch. There has been a push, within the past 15 years, to fly as many contamination monitors as possible in order to more fully understand the mechanisms involved in space contamination, and to validate our analytical models.

The Space Shuttle program was one of the first launch vehicle programs to incorporate contamination monitors into the demonstration program. The first Shuttle monitors were manifested on the various flights of the Induced Environment Contamination Monitor (IECM), and results have been fully documented in a series of conference proceedings as well as numerous technical reports. Since then, NASA GSFC, MSFC, JSC, and JPL have flown a number of additional monitors in support of contamination and atomic oxygen materials degradation studies.

The following list identifies some of the flight contamination monitors which have been flown, to date:

· The GSFC Contamination Monitoring Package (CMP) has been flown (in various configurations) on many Shuttle flights and results are documented in a set of technical papers and reports.

· The MSFC/JSC sponsored Induced Environment Contamination Monitor (IECM) which contained numerous instruments to measure molecular and particulate contamination on the Space Shuttle.

· The Interim Operational Contamination Monitor (IOCM), which was another monitoring package flown on the Shuttle.

· The Ascent Particle Monitor (APM) flown on the Space Shuttle to measure particle redistribution during launch.

· The Long Duration Exposure Facility (LDEF) was a very large-scale program designed primarily to measure atomic oxygen effects and space-exposure effects on a wide variety of materials. The detailed results of this mission may be found in a host of documentation and conference proceedings.

· The EVEEP, which was a molecular contamination monitor flown as part of the EUVE spacecraft mission.

· The MSX.

· The REFLEX monitor which flew (and will continue to be flown) on various Shuttle missions to measure molecular return flux.

· Numerous monitors flown on Air Force DOD missions; the results of these missions are, however, generally contained in classified documents.

With regard to contamination monitors for specific spacecraft missions, a number of previously flown spacecraft have incorporated contamination monitors into the on-orbit operations. This requires the design, fabrication, testing, and integration of contamination monitoring equipment into the basic spacecraft vehicle. It is most effective to consider the use of flight contamination monitors as early in the spacecraft development program as possible (in the concept and design phases). However, in many cases, the need for contamination monitors has not been identified until later in the development process, and a variety of monitors have been "added" to the spacecraft, after the spacecraft has already been designed (and sometimes, even after the spacecraft has been built!). As an example, the Contamination Experiment Package (CEP) consisting of a collection of QCMs which will be flown on the Shuttle, for the HST Second Servicing Mission (Februrary 1997) to monitor the on-orbit contamination environment during the servicing part of the mission.

Typical flight contamination monitors may be either active or passive, and may consist of the following types of measurement devices:

· QCMs and CQCMs

· Capturing-type contamination collection devices (used primarily on spacecraft which will be returned to earth, so that post-flight analysis may be performed.

· Calorimeters

· Sample trays of materials

· Mass spectrometers

· Pressure Gauges

· Reflectance Measuring devices (CEEM, OPM, etc.) to monitor reflectance changes on an optical surface, as a function of time.

3.3 Guidelines For Analytical Studies

In terms of analytical work associated with a spacecraft mission, the contamination analysis plan is similar to the thermal analysis plan. Just as thermal analyses and predictions are performed at various points in the planning and development of a spacecraft, contamination analyses must also be accomplished. Both molecular mass transport and particulate deposition analyses are performed for spacecraft. The following subsections describe the basic processes involved.

3.3.1 Molecular Analyses

It is recommended that a detailed analysis plan be developed for each spacecraft mission. Usually, a preliminary analysis is performed early in the program, so that results may be used to aid in making design decisions. Then, once the final design is established, a detailed analysis is performed and fine-tuned. This stage aids in verifying the spacecraft design and performance expectations, and is also used to set bakeout acceptance criteria for the hardware. A final, flight prediction analysis is typically performed near the end of spacecraft integration and test, to establish the final estimates of on-orbit contamination levels.

These analyses generally consist of utilizing an existing analytical tool (e.g. SPACE II, Molflux, CAP, ISEM, DSMC, and an entire library of plume definition/effects tools), creating a geometric model of the spacecraft (with critical surfaces well-defined), assigning materials and materials outgassing rates to each surface, assigning temperature profiles to each surface, and then exercising the code. Results are usually reported in mass/unit area, and additional iterations of the runs (with different temperatures, materials, etc.) may easily be accomplished. Once the mass/unit area values are ascertained, it is also possible to perform "effects analyses" to predict the resulting impact on performance. For example, a modeling analysis may predict that 100 Angstroms of silicone will deposit on a critical surface. Then, using different analytical tools (which are usually based on experimental test programs), it is possible to evaluate performance of the optical system with this coating of 100 Angstroms of silicone. A 100 Angstrom layer of silicone, within a UV instrument, can mean significant degradation. Additionally, if one considers specific on-orbit parameters (such as solar exposure), it is possible to further assess the impacts via analytical methods.

Materials properties become an important input factor in the molecular analyses. Outgassing rates, and reemission rates are both input into the codes. The industry has, over the years, developed an extensive materials properties data base, and where possible, the input data is obtained from these previously performed materials tests. It is often necessary to perform materials outgassing testing on specific materials, for which no other data exists. Facilities such as the GSFC MOLEKIT lab, and the Lockheed-Martin Outgassing Testing facility at Sunnyvale are both excellent examples of materials testing laboratories.

3.3.2 Particulate Analyses

Whereas the afore described analyses deal primarily with molecular contamination, there are also other analysis methods used to predict expected particulate contamination levels and effects. The particle analyses vary in methodology, depending on the mission phase. Differing physical principals apply to the various mission phases (e.g., particle fallout values are different in 1g environments versus 0 g environments).

For the ground-based assembly, integration, test, transport, storage, and prelaunch phases, calculations are made based on exposure to the various cleanroom environments. Parameters that effect this analysis are:

· How clean is the air?

· How long is the spacecraft exposed?

· Number of personnel working on and near the spacecraft

· Other activities performed near the spacecraft (drilling, sanding, painting, etc.)

· Test chamber attributes and operations

· Number of scheduled cleanings

· Methods of protection employed

Based on these analyses, it is possible to identify potential hazards or threatening timeframes for the spacecraft critical surfaces, and preparations to protect the spacecraft may be made, well in advance of the activities. In addition, these analysis results may be used to determine the schedule of cleaning for the spacecraft. The analysis may show that contamination builds up quickly in one facility versus another, and more frequent hardware cleaning may be advisable.

For the launch period, vibration and acoustics levels act to remove and relocate particles from surfaces. In addition, the changing gravity levels, and venting of the spacecraft and launch vehicle payload volume become important influencing parameters. There are models and codes to evaluate these events, and determine the resulting particle redistribution during launch.

During the on-orbit mission phases, particles become dislodged from surfaces due to spacecraft operations (solar array openings, aperture cover ejections, attitude and altitude changes) and other phenomena such as micrometeoroid impacts. These particles tend to be ejected into a type of "orbit" around the spacecraft and could potentially interfere with instrument and sensor viewing. There are codes that predict these trajectories (based on particle size, shape, relative velocities of spacecraft and particle, and mass), and then predict the potential for re-encounter with the spacecraft, and subsequent deposition.

In all cases, once the particle deposition predictions are determined, it is then possible to perform effects analyses. For example, after predicting the particle deposition (number and sizes of particles) on an optical element, analyses may be performed to assess the scattering associated with the particles on a mirror, or the transmission loss due to particles obscuring a lens. With these analysis results, spacecraft performance may be predicted, and corrective actions may be taken. At the very least, by knowing the level of particle contamination and the predicted effects, it is possible to more effectively evaluate the flight data (making data corrections for the spurious particulate effects).

3.3.3 Other Analyses

There are many other analyses performed for spacecraft programs that are related to contamination. These include:

· Atomic Oxygen Prediction Analyses

· Predicts atomic oxygen fluence

· Can predict materials erosion rates

· Contamination Effects Analyses

· Thermal properties changes

· Optical properties changes

· Lifetime and performance impacts

· Materials Properties Analyses

· Specific analyses on materials outgassing rates and cumulative amounts

· Particulate generation analyses for specific materials

· Materials aging studies

3.4 Guidelines For Laboratory Investigations

Interspersed throughout the Contamination Engineering discipline are many, varied opportunities for performing laboratory investigations. Lab studies are performed to simulate and study the following types of parameters:

Materials outgassing
Mass transport
Amounts of molecular contamination, under simulated mission conditions
Amounts of particulate contamination
Adhesion properties of contaminants
Relocation potential of contaminants
Simulation of other space environmental parameters (solar exposure, atomic oxygen
exposure, temperature changes, vent impacts, altitude differences, etc.)
Contamination effects
Removal of contaminants from surfaces.

It is difficult to list the various testing facilities since there are so many, located at different institutions. NASA, DOD, industry, and academia are all involved in contamination laboratory testing. Each group has various "state of the art" facilities and is known for certain areas of expertise. For example, the Lockheed-Martin organization in Sunnyvale, as well as the NASA GSFC group, have assembled excellent materials testing facilities to evaluate outgassing. These groups not only perform the necessary lab testing to evaluate materials outgassing, but also have the capability to run the corresponding analytical models to predict outgassing and deposition for spacecraft and instruments.

Deposition and performance degradation testing is generally performed in vacuum chambers so that the space environment may be simulated. Various contamination monitors, such as QCMs and particle detection equipment, are used in the test chambers. The contamination sources used during the tests are well characterized.

There are numerous technical papers and reports which document the testing facilities and results obtained during testing. These are listed in the bibliography.

3.5 Interfacing With Other Subsystems

It is obvious that Contamination Engineering impacts a number of other disciplines and subsystems. Thermal, mechanical, electrical, power and propulsion subsystems are often integrally linked with contamination control (hardware, procedures, monitoring, etc.). Some of the more important interface considerations are discussed in the following sections.

3.5.1 Thermal Subsystem Interfaces

There are a number of areas where thermal and Contamination Engineering fields are closely linked in terms of spacecraft development. The more critical elements to consider are:

· Assisting in the derivation of allowable contamination levels for thermal control surfaces.

· Ensure that the thermal analytical model corresponds with the contamination analytical model.

· Utilize thermal modeling results (temperature predictions) as input to the contamination analyses.

· Perform performance degradation studies (analyses and laboratory) on all thermal control surfaces (radiators, coatings, paints, coolers, etc.) to evaluate the impact of accumulated contamination.

· Provide inputs to the thermal engineers regarding contamination generation potential, and contamination susceptibility for all thermal control surfaces.

· Consult with thermal engineers regarding optimization of spacecraft temperatures to reduce outgassing potential (e.g. limit "hot zones").

· Consult with thermal engineers regarding methods of cleaning and verifying thermal control surfaces.

· Consult with thermal engineers regarding protection methods (bags, covers, purges, etc.) for thermal control surfaces.

· Work with thermal engineers to devise and oversee thermal vacuum testing.

· Evaluate on-orbit performance of thermal control system and contamination effects.

3.5.2 Optical Subsystem Interfaces

Because contamination plays such a crucial role in the success or failure of optical systems, there is a close connection between these two disciplines. The relationship begins with the concept and design phases where potential degradation of optics, due to the presence of contaminants, must be evaluated. Often, optical engineers must modify the subsystem design to reduce the potential for excessive contamination of critical elements. Contamination engineers, on the other hand, are obligated to design and plan an adequate contamination control program to ensure the cleanliness of all optics. This usually includes determining the necessary surface and environmental cleanliness levels, choosing low-contaminating materials, preparing needed protection devices (covers, bags, aperture doors, etc.), and may also include evaluating the need for on-orbit protection and periodic clean-up operations.

3.5.3 Mechanical Subsystem Interfaces

Mechanical subsystems require inputs from Contamination Engineering for the following types of issues:

· Providing recommendations for mechanical component design and materials, based on contamination considerations.

· Assisting in setting allowable limits for contamination levels for mechanical systems. Evaluating contamination generation potentials of mechanical systems and components (gears, motors, any moving parts); perform analyses and experimental studies to verify these levels.

· Assisting mechanical engineers in developing adequate cleaning and verification procedures for mechanical components.

· Designing and performing appropriate vacuum bakeouts and certifications of mechanical components.

· Providing adequate contamination protection (bags, covers, purges, etc.) for components.

· Designing and placing vents

· Performing periodic checks of mechanical system contamination levels throughout assembly, integration, testing, through launch.

· Evaluating on-orbit mechanical component performance and possible detrimental effects of contaminants.

· In a slightly different category, there are a number of contamination monitoring and clean-up devices which require the assistance of mechanical engineers. Mechanical engineering assists the contamination engineer in the design, fabrication, assembly and testing of many contamination components (flight monitors, test fixtures/instruments, on-orbit clean-up devices, etc.).

3.5.4 Electrical and Power Subsystem Interfaces

Both the electrical and power subsystems require assistance and inputs from contamination engineers. Often, it is the electronics boxes and power generating systems which contribute the highest amounts of contamination to the immediate volume surrounding a spacecraft, during the on-orbit mission phase. Electronics boxes and power generating equipment usually reach relatively high temperatures, and are comprised of relatively large amounts of nonmetallic materials (epoxies, plastics, potting compounds, wire tubing, etc.). It is, therefore, extremely important for the contamination engineer to become closely involved in the design and development of these systems components. The following types of issues must be addressed:

· Evaluate all electrical and power subsystem components for contamination potentials.

· Make recommendations for materials selection and design of power generating components.

· Assist in setting allowable deposition requirements for system components.

· Assist in setting limits for how much contamination may be contributed by the electrical and power components.

· Perform a full evaluation of solar arrays for contamination generation, and for susceptibility to deposited contaminants.

· Predict deposition levels on power system components to assess performance degradation.

· Design and perform vacuum bakeouts and certifications of electronics boxes, cables, harnesses, solar arrays, etc. since these components typically contribute a majority of the on-orbit contamination.

· Design and test venting configurations of electronic boxes and power assemblies; make recommendations for vent placement.

· Determine need for additional contamination abatement (e.g. the need for molecular adsorbers or extended high temperature bakeouts) solutions for boxes, electrical volumes, etc.

· Determine the need for special protection measures (covers, bags, purges, etc.) for these components.

3.5.5 Propulsion Subsystem Interfaces

The design and operation of on-orbit propulsion systems is of critical concern to contamination control for the spacecraft. Improperly located thrusters, or highly contaminating fuel, or poorly designed nozzles are examples of propulsion system parameters which can effect overall mission performance. Many a spacecraft has suffered self-contamination due to inappropriate propulsion systems. All types of thrusters from orbit insertion boosters, to smalla attitude control thrusters must be fully evaluated. The following list contains some of the main issues associated with contamination control of the spacecraft propulsion system.

· Perform full evaluations of all types of propulsion systems being considered, early in the design phase. The correct thruster design and fuel selection is of paramount importance to on-orbit contamination levels.

· Perform analytical modeling of proposed thrusters/boosters to assess expected deposition on critical surfaces.

· Utilize state-of-the-art thruster models.

· Don t be naive about the backflow region; backflow has been known to cause serious contamination of critical surfaces not in the direct plume impingement volume.

· Make decisions on preferred thruster type and location based on these analyses.

· Work with propulsion system engineers to determine operational scenarios (firing sequences, steady-state vs. pulse firings, duration, direction, limits, inhibit times, etc.).

· If possible, plan for and perform thruster firing testing; incorporate multiple contamination detection monitors during testing.

· Be prepared to evaluate on-orbit performance of thermal control surfaces and contamination detection devices during thruster operations.

3.6 Atomic Oxygen Effects

Although this space effect, is basically a materials degradation issue, there are many connections to contamination and it is worth addressing in a bit more detail, here.

With the advent of the Space Shuttle program in the early 1980 s, it was possible to examine returned space hardware. We were able to study, in detail, the difference between what was sent up, and what returned to Earth. One of the first changes which was noticed, was that many of the surface paints and coatings of the Space Shuttle were changed. Although, some level of concern had previously been voiced regarding the potential degradation of materials due to atomic oxygen exposure, the level of degradation was surprising. Some coatings had changed color, others had turned to powder, others were eroded away.

Much attention was given to these changes and a wide variety of testing and simulation facilities were constructed to try and simulate the level of atomic oxygen fluence experienced at Space Shuttle altitudes. In addition, computer models were generated to predict atomic oxygen densities and resulting potential degradation. In conjunction with these ground-based activities, several flight experiment programs were initiated and flown to actually measure atomic oxygen erosion of materials. The LDEF experiment package, was the grandest of these flight experiments, holding hundreds of different samples and experiments, and flown at low earth altitudes for several years. There is an enormous amount of information published on the results of the LDEF experiment (see 4.2 Related Works).

Suffice it to say, that the erosion of materials, at low earth orbits, due to the impingement of atomic oxygen molecules, is very real. Each spacecraft mission must be evaluated, in terms of the potential for surface erosion. And, wherever possible, atomic oxygen resistant materials should be selected and analyses to predict erosion for the mission should be performed.

In terms of contamination levels, the effect of this materials erosion must be considered. Not only will the materials erode away, but the properties of the surface will change drastically. Thermal and optical properties will be greatly affected. Each material and surface property must be studied. In addition, the eroded material now represents a source of contamination for the rest of the spacecraft. Eroded bits of paint, kapton, etc. may redeposit on sensitive spacecraft surfaces and contribute to the overall contamination deposition levels. This must also be evaluated.

3.7 New and Future Contamination Technologies

The world of Contamination Engineering is changing, even as this document is being written. NASA and DOD are still funding the development of new ideas (at a reduced level due to the inevitable budget cutting exercises) and works are continually being published on the viability of new technologies and applications. A good source for learning about these new ideas is to obtain conference proceedings from some of the more popular contamination organizations. These groups include:

· Society of Photo-Optical Instrumentation Engineers (SPIE) - usually holds large conferences twice a year

· Institute of Environmental Sciences (IES) - usually holds annual meetings

· AIAA - annual conference

· ICCCS - International Contamination Control Conference held every four years

· ESA Materials Symposium - International conference held every other year

In addition, the NASA Small Business Innovative Research (SBIR) program is aimed at soliciting new ideas from the public and small businesses. The program is designed to supply funding for worthy new ideas with the goal of proving the feasibility and marketability of the ideas. Consult with the SBIR office at NASA Headquarters for more information on this project. A yearly request for proposals is published each year and final reports on each funded SBIR are available to the public.

The following list summarizes some of the new technology ideas currently being investigated by the Contamination Engineering community. See Section 4.2 Related Works for additional publications on the subjects:

· 1. Molecular Adsorbers: (Both JPL and GSFC have published numerous works on this subject.)
Includes the use of adsorbent materials (e.g. Zeolite) in spacecraft high outgassing volumes, or placed in spacecraft vents, to "filter" out and trap contaminants.

· 2. CO2 "Snow" Cleaning of Hardware:
A new method of cleaning hardware by spraying surfaces with a cryogenic CO2 which then tends to evaporate-away the contaminants; being considered for on-orbit use.

· 3. New Coatings:
Coatings are being developed to provide improved thermal performance, be more resistant to atomic oxygen erosion, be less impacted by contaminant deposition, etc.

· 4. On-orbit Cleaning Devices:
Many different techniques for cleaning critical elements, during the on-orbit period, to extend or improve instrument performance are being studied.

· 5. Ground Cleaning Techniques:
New methods for achieving ultra-clean surfaces are being investigated.

· 6. Improvements in Thermal Vacuum Bakeouts:
Ways of improving methods of vacuum bakeouts for hardware are under study. This includes developing bakeout boxes, with QCMs installed at critical locations, and measuring the total outgassing from an item.

· 7. New Cleanroom Technologies:
Includes the development of new garments, equipment, filtration, monitoring, etc.

· 8. Contamination Monitors:
Includes the development of new methods for detecting and measuring contaminants, both during ground activities and monitors for on-orbit spacecraft operations.

4.0 .WORKS CITED

There have been numerous works cited throughout this document. The user of encouraged to access these documents for further information on this complex field of Contamination Engineering.

Section 4.1 provides a summary of all the reference works specifically mentioned within this report.

In addition, as a means for pointing the reader to additional information, a list of related bibliographical documents is presented in Section 4.2.

Finally, Section 4.3 provides tables of industry and government contamination-related standards, specifications, practices, methods, etc.

4.1 References Cited

The references cited within this document are presented, based on the section of the document in which they appear. The references are as follows:

4.2 Related Works

The following sections provide lists of related material which may be of interest to the reader.

4.2.1 Molecular Contamination

1. Hall, D. F., "Flight Measurement of Contamination Effects on Fused Silica Mirrors", SPIE Conf., Denver, CO, Aug 1996.

2. Tveekrem, J. L., Leviton, D. B., Fleetwood, C.M., and Feinberg, L. D., "Contamination-Induced Degradation of Optics Exposed to the HST Interior", SPIE Conf., Denver, CO, Au 1996.

3. Shaw, C. G., "Wavelength and Coverage Dependence of Spacecraft Photodeposition", SPIE Conf., Denver, CO, Aug 1996.

4. Arnold, G.s., and Luey, K. T., "Photochemically Deposited Contaminant Film Effects", SPIE Conf., Denver, CO, Aug 1996.

5. Hunter, W. R., "Optical Contamination: Its Prevention in the XUV Spectrographs Flown by the US Naval Research Laboratory in the Apollo Telescope Mount", Applied Optics, April, 1977.

6. Allan, T.H., Bonham, T. E., and Hughese, T. A., "Investigation of Contamination Effects on Thermal Control Materials", MDAC Co., AFML-TR-76-5, March 1976.

7. O Donnell, T., "Evaluation of Spacecraft Materials and Processes for Optical Degradation Potential", SPIE Proceedings, May 1982.

8. Corbin, W. E., and McKeown, D., "Space Measurements of the Contamination of Surfaces by OGO-6 Outgassing and Their Cleaning by Sputtering and Desorption, Space Sim., NBS Special Pub. 336, Oct.1970.

9. Glassford, A. P. M., "Analysis of the Accuracy of a Commercial Quartz Crystal Microbalance", Proc. of AIAA 11th Thermophysics Conference, July 1976.

10. Kruger, R., "A Contamination Experiment Investigating the Failure of the Nimbus IV Filter Wedge Spectrometer", Proc. Space Sim., IES, NASA SP-298, May 1972.

11. Kruger, R., "Outgassing Characteristics of Two Nimbus Thermal Blankets", GSFC report x-322-73-132, May 1973.

12. Kruger, R., "Evaluating a Contamination Hazard With an RGA", Proc. USAF/NASA Intl. Spacecraft Contamination Conference, AFML-TR-78-190, NASA-CP-2039, March 1978.

13. Committee Report on Caprolactam Contamination, NASA GSFC, HST Project, Sept. 29, 1984.

14. Scialdone, J. J., "An Equivalent Energy for the Outgassing of Space Materials", NASA TN-D-8294, GSFC, August 1976.

15. Glassford, A. P. M., and Liu, C. K, "Characterization of Contamination Generation Characteristics of Satellite Materials", AFWAL-TR-83-4126, Vol. 1, November 1983.

16. Colony, J. A., and Gross, F. C., "A Practical Guide for Identification and Control of Spacecraft Contaminants", MTR No. 755-009, NASA GSFC, May 1974.

17. McClellan, M. S., "Clean Room Considerations for Avoiding Molecular Contamination", J. Env. Sci., IES, Sep-Oct 1985.

18. Goldsmith, J. C., and Nelson, E. R., "Molecular Contamination in Environmental Testing at GSFC", Space Sim., NBS Special Pub. 336, Oct 1970.

19. Scialdone, J. J., "Self Contamination and Environment of an Orbiting Spacecraft", NASA TN-D-6645, GSFC, May 1972.

20. Naumann, R. J., "Contamination Assessment and Control in Scientific Satellites", NASA TN-D-7433, MSFC, Oct 1973.

21. Maag, C., and Phillips, A., "Maintenance of Contamination Sensitive Surfaces on Board Long-Term Space Vehicles", J. Eng. Sci., IES, Jul-Aug 1984.

22. Kruger, R., and Shapiro, H., "Experiments on the Effect of UV on Contamination inVacuum Systems", NASA TN-D-81999, GSFC, Jun 1980.

23. Jones, P. F., "Radiation Effects on Contaminants from the Outgassing of Silastic 140 RTV", Proc. Symp. on Space Sim, NASA SP-298, GSFC, May 1972.

24. Fleischauer, P., D., and Tolentino, L., "The Far UV Photolysis of Polymethlphenylsiloxane Films on Quartz Substrates", Proc. 7th Conf. on Space Sim., NASA SP-336, GSFC, Nov 1973.

25. Haas, G., and Hunter, W.R., "Laboratory Experiments to Study Surface Contamination and Degradation of Optical Coatings and Materials in Simulated Space Environments", Applied Optics, Sep 1970.

26. Osantowski, J. F., "Contamination Sensitivity of Typical Mirror Coatings - a Parametric Study", Proc. Int. Soc. for Opt. Eng., May 1982.

27. Bremmer, J. D., "General Contamination Criteria for Optical Surfaces", Proc. Soc. for Opt. Eng., Apr 1981.

28. Dushman, S., Scientific Foundations of Vacuum Technology, J. Wiley and Sons, Publisher, 1962.

29. Enlow, D. L., "Contamination Studies in a Space Simulated Environment", Space Sim. Conf. NBS Special Pub. 336, Oct 1970.

30. Muscari, J. A., and O Donnell, T., "Mass Loss Parameters for Typical Shuttle Materials", Proc. Int. Soc. for Opt. Eng., Apr 1981.

31. Cull, R., "Improved Materials Characterization for Spacecraft Applications", 13th Space Sim. Conf., NASA, Pub. 2340, Oct 1984.

32. Kruger, R., "Suggested Criteria for an Outgassing Test", Memorandum, Oct. 1981.

33. Campell, W. A., Marriott, R. S., and Park, J. J., "Outgassing Data for Selecting Spacecraft Materials", NASA Ref. Pub 1124, GSFC, Jun 1984.

34. Borson, E. N., "Thermal Vacuum Bakeout Conditioning for Molecular Contamination Control", Proc. 31st Ann. Tech. Mtg., IES, Apr-May 1985.

35. Glassford, A.P.M., "Outgassing Behavior of Multilayer Insulation Material", J. Spacecraft, Dec. 1970.

36. Glassford, A.P.M., Garrett, J. W., and Liu, C. K., series of publications on "Characterization of Contamination Generation Characteristics of Satellites", AFWAL contracts.

37. Leger, L., "Gaseous Contamination Concerns", USAF/NASA Intl. SC Contam. Conf., NASA CP-2080, Mar 1978.

38. Triolo, J. J., Heaney, J. B., Haas, G., and Ramsey, J.B., "Thermal Emissivity and Solar Absorptivity of Aluminum Coated with Double Layers of Aluminum Oxide and Silicon Oxide", Applied Optics, Jun 1971.

39. Borson, E. N., Watts, E.J., and To, G. A., "A Standard Method for Measurement of NVR on Surfaces", SD-TR-89-63, Aerospace Corporation, August 1989.

40. Muscari, J. A., Rantanen, R. O., and Pugel, N. J., "Applicability of TGA to Space Contamination", USAF/NASA Intl. SC Contam. Conf, 1978.

41. Zwaal, A., "Outgassing Measurements on Materials in Vacuum Using a Vacuum Balance and QCMs", USAF/NASA Intl. SC Contam. Conf., 1978.

4.2.2 Particulate Contamination

1. Brent, D.A., Gor, D., and Blakkolb, B.K., "Ascent Phase Particulate Contamination Modeling Using Finite Element Methods", SPIE Conf., Denver, CO, Aug 1996.

2. Green, B. D., Mulhall, P. A., "Particle Detection by Optical Systems on MSX", SPIE Conf., Denver, CO, Aug 1996.

3. Rapa, A. C., "Surface Migrating Particulate Contamination", J. of Env. Sci., Nov-Dec 1980.

4. Barengoltz, J., "Spacecraft Recontamination", 8th Conf. on Space Sim., NASA SP-379, 1975.

5. Muscari, K. P., "The Particulate Environment Around Sensitive Spacecraft", AIAA 20th Thermophysics Conf., AIAA-85-0955, 1985.

6. Miller, E. R., "STS-2, -3, -4 IECM Summary Report", NASA TM-82524, MSFC, 1983.

7. David, R. W., "Evaluation and Comparison of Airborne and Settled Particulate Contamination For Controlled Environment Workstations", 24th SAMPE Symp., Society for the Advancement of Material and Process Engineering, 1979.

8. Knollenberg, R. G., "The Measurement of Particle Sizes Below 0.1 Micrometers", J. Env. Sci., IES, Jan-Feb 1985.

9. Carosso, P. A., and N. J. P., "Surface Contamination Monitoring by the Measurement of Scattering Distribution Functions", J. Env. Sci., May-Jun 1987.

10. Carosso, P. A., and N. J. P., "Role of Scattering Distribution Functions in Spacecraft Contamination Control Practices", Applied Optics, April 1986.

11. Bakale, D. K., and Bryson, C. E., "Surface Analysis: Detection and Measurement of Microcontaminants", Microcontamination Magazine, Publisher: Cannon Communications Inc., Oct-Nov 1985.

12. Koellen, D. S., and Saxon, D. I., "Applications of Surface Analysis: Detection and Identification of Contamination on SemiConductor Surfaces", Microcontamination Magazine, 1985.

13. Mittal, K. L., "Surface Contamination: An Overview" , Proc. 4th Intl. Symp. on Contam. Control, ICCCS, IES, 1978.

14. Schneider, H. W., "Brushless Cleaning of Solar Panels and Windows", NASA Tech. Briefs, Fall/Winter 1981.

15. Bartell, F. O., Dereniak, E. L., and Wolfe, W. L., "Radiation Scattering in Optical Systems", Proc. SPIE, 1980.

16. Nicodemus, F. E., "Directional Reflectance and Emissivity of an Opaque Surface", SPIE Proc. 1980.

17. Pugel, N. J., "Analysis of Prelaunch Particulate Contamination ", SPIE Conf. Proc., May 1982.

18. Scialdone, J. J., "Particulate Contaminant Relocation During Shuttle Ascent", SPIE Conf. Proc., May 1987.

19. Barengoltz, J. B., "Calculating the Obscuration Ratio Due to Particle Surface Contamination", NASA Tech. Brief, Aug. 1989.

20. Raab, J. H., "Particulate Contamination Effects on Solar Cell Performance", Martin Marietta report MCR-86-2015, Rev. A., Jan 1987.

21. Jarossy, F. J., and Mason, L. W., "An Analytical Technique for Predicting the Effect of Particulate Contamination on Direct Scatter in an Optical Sensor", SPIE Conf., 1986.

22. Young, R. P., "Mirror Scatter Degradation by Particulate Contamination ", SPIE Conf., Jul 1990.

23. Chen, P.T., and Hedgeland, R. J., "Cleanliness Correlation by BRDF and PFO Instruments", SPIE Conf., Aug 1989.

24. Ma, P. T., Fong, M. C., and Lee, A. L. , "Surface Particle Obscuration and BRDF Predictions", SPIE Proc., 1989.

4.2.3 Contamination Control For Spacecraft

1. Peterson, R. V., "MODIS Contamination Control Requirements and Implementation", SPIE Conf. Aug. 1996.

2. Hansen, P. A., Hughes, D.W., Triolo, J.J., Sanders, J., Smith, K., Chivatero, C., and Dell, L., "HST Second Servicing Mission Contamination Control Program", SPIE Conf. Aug 1996.

3. Hansen, P. A., Albyn, K., Nguyen, C., and Borson, E.N., "Orbiter Contamination Controls During Maintenance Down Periods: An Approach for Sensitive Payloads", SPIE Conf., Denver, CO, Aug. 1996.

4. Hansen, P. A., Hedgeland, R. J., and Hughes, D. W., "An Integrated Approach for Contamination Control and Verification for the HST First Servicing Mission", SPIE Proc., Optical System Contamination: Effects, Measurements, and Control IV, July 1994.

5. Hansen, P. A., and Millard, J. M., "EOS/NOAA Candidate Propulsion System Assessment and Instrument Contamination Requirements", SPIE Conf. Proc., 1987.

6. Haffner, J. W., "Contamination Studies on the Teal Ruby Telescope", AIAA 20th Thermophysics Conf., Jun 1985.

7. Naumann, R. J., "Skylab-Induced Environment", Progress in Astro. and Aero., AIAA, 1975.

8. Pugel, N. J., "Insights Into Contamination Control at the Shuttle Payload Integration Facility", SPIE Conf. Proc., 1981.

9. Kohl, J. L., and Weiser, H., "Shuttle Contamination Effects on Ultraviolet Coronagraphic Observations", SPIE, 1981.

10. McKeown, D., Cox, V.H., and Peterson, R. V., "Analysis of TQCM Surface Contamination Absorbed During the Spacelab 1 Mission", AIAA Conf., Nov. 1985.

11. Abrams, E., and Carosso, N. J. P., "Science Objectives Lead to Contamination Requirements for the COBE", SPIE, Jul 1990.

12. Carosso, N.J. P., "Space Station Users Contamination Requirements", SPIE, May 1987.

13. Carosso, P. A., "UARS Contamination Control Approach", SPIE Conf., May 1987.

14. Borson, E. N., "Contamination Control Documents for Use in SOWs and CCPs for Spacecraft Programs", Aerospace report No. TOR-93-3411-5, Sep 1993.

15. Borson, E.N., "Spacecraft Contamination Experience", NASA/SDIO Space Env. Eff. Workshop, NASA CP-3035, June 1988.

16. Borson, E.N., "The Control of Contamination - Where are we Going?", Proceedings USAF/NASA Intl. SC Contam. Conf., 1978.

4.2.4 Contamination Analyses

1. Woronowicz, M. S., and Chen, P. C., "Investigation of Molecular Angular Distribution and its Influence on Contamination Transmission", SPIE Conf., Denver, CO, Aug. 1996.

2. Brent, D. A., Cottrell, F.D., and Henderson, K.A., "Modeling of Spacecraft Using a Modifed Version of MOLFLUX and Comparisons With a Continuous Flux Model", SPIE Conf., Denver, CO, Aug 1996.

3. Rantanen, R.O., and Gordon, T., "On-Orbit Transport of Molecular and Particulate Contaminants", SPIE Conf., Denver, CO, Aug 1996.

4. Chivatero, C., "Assessment of Contamination Effects on HST Due to Venus Observations", SPIE Conf., Denver, CO., Aug 1996.

5. Scialdone, J. J., "Predicting Spacecraft Self-Contamination in Space and in a Test Chamber", Proc. Space Sim. Conf., NASA SP-298, 1972.

6. Zeiner, E. A., AESC Multinodal Free Molecular Contamination Transport Model", 8th Conf. on Space Sim., NASA SP-379, Nov. 1975.

7. Maag, C. R., and Millard, J. M., "Spacecraft Contamination Modelling Development", Proc. of USAF/NASA Int. SC Contam.Conf., AFML-TR-78-190, NASA CP-2039, Mar 1978.

8. Hoffman, R. J., et al, "The Contam 3.2 Plume Flowfield Analysis and Contamination Prediction Program; Analysis Model and Experimental Verification", AIAA 20th Thermophysics Conf., AIAA-85-0928, Jun 1985.

9. Bareiss, L. E., Payton, R. M., and Papazian, H. A., "Shuttle/Spacelab Contamination Environment and Effects Handbook", NASA contractor report 3993, MSFC, Sept 1986.

10. Barengoltz, J. B, Millard, J. M., Jenkin, T., and Taylor, D. M., "Modeling of Internal Contaminant Deposition on a Cold Instrument Sensor", SPIE Conf. Proc., July 1990.

11. Fong, M. C., Phillips,J. R., and Panczak, T. D., "Monte Carlo Simulation of Contaminant Transport and Deposition on Complex Spacecraft Surfaces", SPIE Conf. Proc., Aug. 1989.

12. Rantanen, R. O., and Gordon, R. D., "Contaminant Buildup on RAM Facing Spacecraft Surfaces", SPIE Conf. May 1987.

13. Zeiner, E. A., " Measurement of Kinetics and Transport Properties of Contaminants Released from Polymeric Sources in Space and Effects on Collecting Surfaces", USAF/NASA Intl. SC Contam. Conf., NASA-CP-2040, Mar 1978.

14. Fong, M. C. ,and Lee, A. L., "BGK Method to Determine Thruster Plume Backscatter", SPIE, Conf. Proc., 1990.

15. Furstenau, R. P., McCay, T. D., and Mann, D. M., "US Air Force Approach to Plume Contamination", SPIE Conf. Proc. Feb. 1980.

16. Maag, C. R., "Backflow Contamination from SRMs", USAF/NASA Intl. SC Contam. Conf., 1978.

17. Glassford, A. P. M., and Liu, C.K., "Contamination Effect of MMH/N2O4 Rocket Plume Product Deposit", J. Spacecraft, Jul-Aug 1981.

4.2.5 Flight Data and On-Orbit Effects

1. Boies, M. T., Uy, O.M., "Total Pressure Sensor Results from the Early Operations Phase of the MSX Mission", SPIE Conf., Denver, CO, Aug. 1996.

2. Wood, B.J., Hall, D.F., Lesho, J.C., Dyer, J.S., and Uy, O..M., "QCM Flight Measurements of Contamination on the Midcourse Space Experiment (MSX)", SPIE Conf., Denver, CO, Aug. 1996.

3. Hansen, P. A., Reaves, B., McIntosh, R., Triolo, J. J., Squires, B., and Maag, C. R., "On-orbit Contamination Monitoring for the HST Second Servicing Mission", SPIE Conf., Denver, CO, Aug 1996.

4. Maag, C.R., VanEesbeek, M., Mitzen, P.S., Stevenson, T. J, and Crisium, M., "Contamination Environment as Measured at the MIR Space Station", SPIE Conf., Aug. 1996

5. Simpson, J. P., and Witteborn, F. C., "Effect of the Shuttle Contaminant Environment on a Sensitive Infrared Telescope", Applied Optics, Aug. 1977.

6. Hall, D. F., and Fote, A. A., "Further Flight Evidence of Spacecraft Surface Contamination Rate Enhancement by Spacecraft Charging", AIAA 19th Thermophysics Conf., Jun 1984.

7. Carre, D. J., and Hall, D. F., "Contamination Measurements during Operation of Hydrazine Thrusters on the SCATHA Satellite", J. Spacecraft and Rockets, Sep-Oct 1983.

8. Fote, A. A., and Hall,D.F., "Contamination Measurements During the Firing of the Solid Propellant Apogee Insertion Motor on the SCATHA Spacecraft", SPIE Conf. Proc., 1982.

9. Arnold, G. S., Young Owl, R. C., and Hall, D. F., "Optical Effects of Photochemically Deposited Contaminant Films", SPIE Conf. Proc., July 1990.

10. Maravin, Hwang, W. C., Arnold, G. S., and Hall, D. F., "Contamination Induced Solar Array Performance", Proc. 23rd Intersociety Energy Conversion Engineering, Conf., Denver, July 1988.

11. Hall, D. F., "Flight Measurement of Molecular Contaminant Environment", ESA 6th Intl Symp. on Materials in Space, Sep 1994.

12. Arnold, G. S., and Hall, D. F., " Contamination of Optical Surfaces", NASA/OSSA Workshop, Hilton Head, South Carolina, 1988.

13. Neff, J. A., Mullen C. R., and Fogdall, L. B., "Effects of a Simulated Synchronous Altitude Environment on Contaminated Optical Solar Reflectors", J. Spacecraft, Jul-Aug 1986.

14. Pence, W. R., and Grant, T. J., "Alpha Sub S Measurements of Thermal Control Coatings on Navstar GPS Spacecraft", Spacecraft Radiative Transfer and Temperature Control, T. E. Horton, editor, Progress in Astronautics and Aeronautics, 1982.

4.2.6 Atomic Oxygen Effects

1. Triolo, J. J., Kruger, R., Straka, S., and Chen, P., "A Comparison of Carbon Depletion on STS-8 With Atomic Oxygen Flux", STAIF Conf., Albequerque, NM, Jan. 1996.

2. Leger, L., Vizentine, J., and Schliesing, J., " A Consideration of Atomic Oxygen Interactions With Space Station", AIAA 23rd Conf., Reno, NV, Jan. 1985.

3. Leger, L., Visentine, J., Kuminecz, J., "Low Earth Orbit Atomic Oxygen Effects on Surfaces", AIAA Conf., Jan. 1984.

4. LDEF Spaceflight Environment Effects Newsletter Series, published by NASA Langley Research Center, Jim Jones.

5. LDEF Materials Workshops, 1990, 91, 92, Conference Proceedings, Langley Research Center.

6. LDEF Mission 1 Experiments, NASA SP-473, 1984.

7. 69 Months in Space: A History of the First LDEF, NASA, NP 149.

8. LDEF - 69 Months in Space, First Post Retrieval Symposium, Parts 1, 2, and 3, CP 3134, Dec. 1991.

9. LDEF - 69 Months in Space, Second Post Retrieval Symposium, Parts 1,2,3,and 4, CP3194, Jun 1992.

10. LDEF- 69 Months in Space, Third Post Retrieval Symposium, Abstracts, CP 10120, Nov. 1993.

4.2.7 Molecular Adsorbers

1. Thomson, S., Chen, P., Triolo, J., Hansen, P. A., and Carosso, N. , "Incorporation of Molecular Adsorbers into Future HST Instruments", SPIE Conf., Aug 1996.

2. Straka, S., Chen, P., Triolo, J., Thomson, S., Carosso, N., and Bettini, R., "TRMM Project Contamination Control Using Molecular Adsorbers", STAIF Conf., Albuquerque, NM, Jan. 1996.

3. Thomson, S., Chen., P., Triolo, J., Carosso, N., "The Use of Molecular for Spacecraft Contamination Control:" STAIF Conf., Albuquerque, NM, Jan. 1996.

4. Barengoltz, J. B., Moore, S., Soules, D., and Voecks, G., "The Wide Field/Planetary Camera 2 (WFPC-2) Molecular Adsorber", JPL Publication, 94-001, Jan. 1994.

4.2.8 Other New Technologies

1. Shaw, C. G., "Nitrogen Snow Cleaning Inside a Large Cryogenic Telescope", SPIE Conf., Aug 1996.

2. Williamson, W. S., Kaufman, D. A., Drolen, B.L., and Ng, K.L., "Low-energy Reactive Plasma Source for On-Orbit Removal of Contamination from Optical Surfaces", SPIE Conf. Aug. 1996.

3. Wallace, S. A., Wallace, D. A., "New Generation of Miniaturized High Mass Sensitivity QCMs for Space Applications", SPIE Conf., Aug. 1996.

4. Peterson, R. V., and Bowers, C., "Contamination Removal by CO2 Jet Spray", SPIE Conf., 1990.

5. Hoenig, S. and Kinkade, K., "Use of Dry Ice and Various Solvents for Removing Flux Contaminants From Printed Circuit Boards", Inside Space ISHM journal, Jan-Feb. 1993.

4.3 Contamination Specifications

The intent of this section is to provide the reader with a detailed list of available contamination-related procedures, specifications, standards, methods, practices, etc.

4.3.1 NASA Standards and Documents

Number Title

NAS1638 Cleanliness Requirements.

NASA-SP-3025 Space Materials Handbook (Supplement 1).

NASA-SP-3051 Space Materials Handbook.

NASA-SP-3094 Spacecraft Material Guide

NASA-SP-5076 Contamination Control Handbook.

NASA-SP-6505 Parts and Materials Application Review

NASA-SP-6507 Parts, Materials, and Processes.

NASA-SP-6507 Parts, Materials, and Process Experience Summary.

NASA-SP-7012 The International System of Units, Physical Constants, and Conversion Tables.

NHB 1700.7A 9 Dec. 1980 Safety Policy and Requirements for Payloads Using the Space Transportation System (STS).

NHB 8060.1C April 1991 Flammability, Odor, and Offgassing Requirements and Test Procedures for Materials in Environments that Support Combustion.

RSA-SUP/2104-1.6 Spacelab Payload SSCCMM Handbook

ES511201 Cleaning Electronic Components.

JPL-0618-251A Particulate Measurement Requirements for MJS 77 Cape Operations and Acceptance Criteria

JPL-0750-107 Present Knowledge of the Solar Constant and Future Observations, Dr. R. C. Willson

FS506092 Cleaning and Contamination Control Procedures for Reaction Control Assemblies.

FS506093 Clean Room Requirements for Reaction Control Assemblies.

FS507296 Outgassing of RF Shielding Gaskets made of Consil-R or Equivalent Silicone Base Product.

STP0413D Maintenance of Cleanliness of Aerospace Hardware

STP0416C Maintenance of Cleanliness of Manned Spacecraft

TS507035 Vacuum Outgassing of Polymers (Micro-VCM Technique).

GSFC-7327 Compilations of Outgassing Data.

GSFC-GEVS-STS General Environmental Verification Specifications for STS Payloads, Subsystems, and Components.

GSFC-SPAR-1 Guidelines for STS Payload Assurance Requirements (SPAR) for Free-Flyer Spacecraft and Instruments.

JSC-SPEC-C-20C 14 June 1976 Water, High Purity, Specification for.

JSC-HDBK-94 Fluid System Cleanliness-Verification is Draining, Purging, and Flushing Operations.

JSCM 5322B Contamination Control Program Requirements Manual

JSC-07572 List of Materials Meeting JSC Vacuum Stability Requirements.

JSC-No Number Space Station Standards Manual

JSC-08962U, Addendum 10 Compilation of the VCM Data of Nonmetallic Materials.

JSC-HDBK-10419906 Cleanliness Levels

NSTS 07700, Vol. X Space Shuttle Flight and Ground System Specification.

NSTS 07700, Vol. XIV, Appendix 5 Ground Operations.

NSTS 08131B 1989 National Space Transportation System, Contamination Control Plan.

NSTS 08242 1988 National Space Transportation System, Limitations for Nonflight Materials and Equipment Used In and Around the Space Shuttle Orbiter Vehicles.

SD72-SH-0172A Space Shuttle Orbiter Materials Control and Verification Plan.

SE-M-0096A Materials and Processes Requirements for JSC-Controlled Payloads, General Specification.

SE-R-0006C 1990 General Specification, Space Shuttle System Requirements for Materials and Processes.

SE-S-0073E, Change 35, Specification, Space Shuttle Fluid Procurement and Use Control.

SN-C-0005C 15 Feb. 1989 National Space Transportation System, Contamination Control Requirements.

SP-5076 Contamination Control Handbook

SR-ER-0006 Part, Material, and Process Specification.

SP-R-0022A 9 Sept. 1974 General Specification, Vacuum Stability Requirements of Polymeric Material for Spacecraft Application.

K-STSM-14.1 1991 Launch Site Accommodations Handbook for Payloads.

K-STSM-14.2.1 B July 1993 KSC Payload Facility Contamination Control Requirements/Plan.

KCI-HB-5340.1 15 Dec. 1983 Payload Facility Contamination Control Implementation Plan.

KHB 5330.10 1991 KSC Foreign Object Control Program.

KSC-C-123F 19 Oct. 1979 Specification for Surface Cleanliness of Fluid Systems.

KSC-C-182 Gas Cleanliness Requirements for Operational Gaseous Nitrogen, Helium, and Hydrogen Systems at Complex 39, Specification for

KSC-SPEC-P-0011 Particulate Screening on Space Shuttle Ground Systems.

KVT-PL-0025E April 1995 Shuttle Facility/Orbiter Contamination Control Plan.

MMA-1985-79, Rev. 2 15 July 1988 Standard Test Method for Evaluating Triboelectric Charge Generation and Decay.

VCP-85-485 Cargo Operations Contamination Control Plan

50M02412 ATM Cleanliness Requirements

50M02442W ATM Material Control

50M02446 ATM Contamination

50M16944 Cleanliness and Vacuum Baking of ATM Television.......

MSFC-HDBK-527F Material Selection Guide for MSFC Spacelab Payloads

MSFC-PROC-151A Contamination Control and Environmental Protection of Space Launch Vehicles, Spacecraft Experiments, and Associated Equipment, Procedure.

MSFC-PROC-166D 1967 Procedure for Cleaning, Testing and Handling of Hydraulic System Detailed Parts, Components, Assemblies, and Hydraulic Fluids for Space Vehicles.

MSFC-PROC-1721 Tape Lift Particle Counting Procedure

MSFC-PROC-1831A The Analysis of Nonvolatile Residue Content Based on ASTM F 331-72

MSFC-PROC-1832B Sampling and Analysis of NVR Content on Critical Surfaces

MSFC-PROC-2228 Outgassing Test Procedure for Non-Metallic Materials Associated with Contamination Sensitive Surfaces in a Thermal Vacuum Environment.

MSFC-PROC-404 20 Oct. 1964 Procedure, Gases, Drying and Preservation, Cleanliness Level and Inspection Methods.

MSFC-PROC-536 Contamination Control Due to Vacuum Outgassing

MSFC-SPEC-1238A Thermal Vacuum Bakeout Specification for Contamination Sensitive Hardware.

MSFC-SPEC-1443A Sept. 1995 Outgassing Test for Non-Metallic Materials Associated with Contamination Sensitive Surfaces in a Thermal Vacuum Environment.

MSFC-SPEC-164A Cleanliness of Components for Use in Oxygen, Fuel, and Pneumatic Systems, Specifications for

MSFC-SPEC-164A 1970 Specification for Cleanliness of Components for Use in Oxygen, Fuel, and Pneumatic Systems.

MSFC-SPEC-2223 Outgassing Test for Materials Associated with Sensitive Surfaces Used in an Ambient Environment.

MSFC-SPEC-527C Material Selection Guide

MSFC-SPEC-548B Vacuum Baking of Electrical Connectors

MSFC-SPEC-548B Specification for Vacuum Baking of Electrical Connectors for Spacelab Payloads.

MSFC-SPEC-578 ATM Contamination/Outgassing

MSFC-SPEC-580 Outgassing, Thermal Vacuum.

MSFC-SPEC-684 Vacuum Baking of Electrical Cables.

MSFC-SPEC-684 Specification for Vacuum Baking of Electrical Cab.........

MSFC-STD-246B

Standard for Design and Operational Criteria of Controlled Environmental Areas.

MSFC-STD-343A with Supplement 2 30 Jan. 1968 Preservation, Packaging, Packing, Marking, Handling, and Shipping of Space Vehicle Components, Parts, and Associated Equipment.

MSFC-STD-506B Materials and Processes Control

S&E-QUAL-ARA-007 23 May 1968 Sampling and Analyzing Hydrocarbon Contamination on Critical Surfaces.

S&E-QUAL-ARA-021 4 Feb. 1969 Determination of Total Hydrocarbon by Means of Flame Ionization.

S&E-QUAL-ARA-026 3 Nov. 1969 Procedure for Certification and Monitoring of Environmentally Controlled Areas.

4.3.2 ASTM Documents

Number Title

A380-94 Practice for Cleaning and Descaling of Stainless Steel Parts, Equipment, and Systems.

C 690-86(1992) Test Method for Particle Size Distribution of Alumina or Quartz by Electric Sensing Zone Technique.

C 813-90(1994) Test Method For Hydrophobic Contamination on Glass by Contact Angle Measurement.

D 257-93 Test Methods for D-C Resistance or Conductance of Insulating Materials.

D 543-87 Test Method for Resistance of Plastics to Chemical Reagents.

D 1125-91 Test Methods for Electrical Conductivity and Resistivity of Water.

D 1193-91 Specification for Reagent Water.

D 1239-92 Test Method for Resistance of Plastic Films to Extraction by Chemicals

D 1356-95a Terminology Relating to Atmospheric Sampling and Analysis.

D 1357-95 Practice for Planning the Sampling of the Ambient Atmosphere.

D 1605 Practices for Sampling Atmospheres for Analyses of Gases and Vapors.

D 1739-94 Method for Collection and Analysis of Dustfall (Settleable Particulate Matter).

D1889-94 Method for Turbidity of Water.

D 1914-68(1983) Practice for Conversion Units and Factors Relating to Atmospheric Analysis.

D 2009-65(1990) Practice for Collection by Filtration and Determination of Mass, Number, and Optical Sizing of Atmospheric Particulates.

D 2109-92 Methods for Nonvolatile Matter in Halogenated Organic Solvents and Their Admixtures.

D 2276-94a Method for Particulate Contaminant in Aviation Fuel by Line Sampling

D 2579-93 Methods for Total and Organic Carbon in Water

D 2580-94 Method for Phenols in Water by Gas-Liquid Chromatography.

D 2908-91 Practice for Measuring Volatile Organic Matter in Water by Aqueous-Injection Gas Chromatography

D 2910-85 Practice for the Removal of Organic Matter from Water by Activated Carbon Absorption.

D 2986-95 Practice for Evaluation of Air Assay Media by the Monodisperse DOP (Dioctyl Phthalate) Smoke Test.

D 3249-95 Practice for General Ambient Air Analyzer Procedures.

D 3609-91 Practice for Calibration Techniques Using Permeation Tubes.

D 3686-95 Practice for Sampling Atmospheres to Collect Organic Compound Vapors (Activated Charcoal Tube Adsorption Method).

D 3687-95 Practice for Analysis of Organic Compound Vapors Collected by the Activated Charcoal Tube Adsorption Methods.

D 3861-91 Method for Quality of Water-Extractable Matter in Membrane Filters.

D 3862-80(1990) Method for Retention Characteristics of 0.2 m Membrane Filters Used in Routine Filtration Procedures for the Evaluation of Microbiological Water Quality.

D 3863-87(1993) Method for Retention Characteristics of 0.4 to 0.45 m Membrane Filters Used in Routine Filtration Procedures for the Evaluation of Microbiological Water Quality.

D 3864-79(1990) Guide for Continual On-Line Monitoring Systems for Water Analysis.

D 3870-91 Practice for Establishing Performance Characteristics for Colony Counting Methods in Microbiology.

D 3979-86 Method for Particulate Matter in Trichlorotrifluoroethane.

D 4012-81(1990) Method for Adenosine Triphosphate (ATP) Content of Microorganisms in Water.

D 4096-91 Method for Determination of Total Suspended Particulate Matter in the Atmosphere (High-Volume Sampler Method).

D 4128-94 Practice for Identification of Organic Compounds in Water by Combined Gas Chromatography and Electron Impact Mass Spectrometry.

D 4378-92 Practice for In-Service Monitoring of Mineral Turbine Oils for Steam and Gas Turbines.

D 4453-91 Practice for Handling Ultra-Pure Water Samples.

D 4455-85(1990) Method for Enumeration of Aquatic Bacteria by Epifluorescence Microscopy Counting Procedure.

D 4496-87(1993) Method for D-C Resistance or Conductance of Moderately Conductive Materials.

D 4517-85(1994) Method for Low Level Total Silica in High-Purity Water by Flameless Atomic Absorption Spectroscopy.

D 4519-94 Method for On-Line Determination of Anions and Carbon Dioxide in High-Purity Water by Cation Exchange and Degassed Cation Conductivity.

D 4526-85(1991) Practice for Determination of Volatiles in Polymers by Headspace Gas Chromatography.

D 4536-91 Method for High Volume Sampling for Solid Particulate Matter and Determination of Particulate Emissions.

D 4597-92 Practice for Sampling Workplace Atmospheres to Collect Organic Gases or Vapors with Activated Charcoal Diffusional Samplers.

D 4598-87 Practice for Sampling Workplace Atmospheres to Collect Organic Gases or Vapors with Liquid Sorbent Diffusional Samplers.

D 4754-93 Method for Two-Sided Liquid Extraction of Plastic Materials Using FDA Migration Cell.

D 5116-90 Guide for Small-Scale Environmental Chamber Determinations of Organic Emissions From Indoor Materials/Products.

D 5127-90 Guide to Electronic Grade Water.

D 5173-91 Method for On-Line Monitoring of Carbon Compounds in Water.

D 5466-93 Methods for the Determination of Volatile Organic Chemicals in Atmospheres (Canister Sampling Methodology).

E 20-85 Practice for Particle-Size Analysis of Particulate Substances in the Range of 0.2 to 75 m by Optical Microscopy.

E 168-92 Practices for General Techniques of Infrared Quantitative Analysis.

E 169-93 Practices for General Techniques of Ultraviolet-Visible Quantitative Analysis.

E 204-92 Practices for Identification of Material by Infrared Absorption Spectroscopy, Using the ASTM Coded Band and Chemical Classification Index.

E 334-90 Practices for General Techniques of Infrared Microanalysis.

E 337-84(1990) Method for Measuring Humidity with a Psychrometer (The Measurement of Wet-Bulb and Dry-Bulb Temperatures).

E 355-77(1989) Practice for Gas Chromatography Terms and Relationships.

E 380-93 Practice for Use of the International System of Units (SI) (the Modernized Metric System).

E 573-81(1990) Practices for Internal Reflection Spectroscopy.

E 594-93 Practice for Testing Flame Ionization Detectors Used in Gas Chromatography.

E 673-95a Terminology Relating to Surface Analysis.

E 840--91 Practice for Using Flame Photometric Detectors in Gas Chromatography.

E 1252-94 Practice for General Techniques for Qualitative Infrared Analysis.

F 35-68(1988) Practice for Identification of Minute Crystalline Particle Contaminants by X-Ray Diffraction.

F 59-68(1988) Method for Identification of Metal Particulate Contamination Found in Electronic and Microelectronic Components and Systems Using the Ring Oven Technique, with Spot Tests.

F 60-68(1983) Method for Detection and Estimation of Microbiological Contaminants in Water Used for Processing Electron and Microelectronic Devices.

F 308 Practice for Sampling Gas Blow-Down Systems and Components for Particulate Contamination by manual Method

F 311-78(1992) Practice for Processing Aerospace Liquid Samples for Particulate Contamination Analysis Using Membrane Filters.

F 312-69(1992) Method for Microscopial Sizing and Counting Particles from Aerospace Fluids on Membrane Filters.

F 316-86 Method for Pore Size Characteristics of Membrane Filters for Use with Aerospace Fluids.

F 322 Method for Determining the Quality of Calibration Particles for Automatic Particle Counters.

F 324-75(1980) Method for Nonvolatile Residue of Volatile Cleaning Solvents Using the Solvent Purity Meter

F 329-78(1983) Practice for Sampling and Measurement of Particulate Contamination in Liquids Using an In-Line Automatic Monitor.

F 488-79 Test Method for Total Bacterial Count in Water.

F 490-77 Method for Microscopial Sizing and Counting Particles on Membrane Filters Using Image Shear.

F 583-82(1990) Method for Photoresist Cleanliness·Filterability

F 660-83(1993) Practice for Comparing Particle Size in the Use of Alternative Types of Particle Counters.

F 661-92 Practice for Particle Count and Size Distribution Measurement in Batch Samples for Filter Evaluation Using an Optical Particle Counter.

F 662-86(1992) Test Method for Measurement of Particle Count and Size Distribution in Batch Samples for Filter Evaluation Using an Electrical Resistance Particle Counter.

F 740-82a(1993) Terminology Relating to Filtration.

F 778-88(1993) Methods for Gas Flow Resistance Testing of Filtration Media.

F 795-88(1993) Practice for Determining the Performance of a Filter Medium Employing a Single-Pass, Constant-Rate, Liquid Test.

F 796-88(1993) Practice for Determining the Performance of a Filter Medium Employing a Single-Pass, Constant-Pressure, Liquid Test.

F 797-88(1993) Practice for Determining the Performance of a Filter Medium Employing a Multipass, Constant-Rate, Liquid Test.

F 838-83(1993) Method for Determining Bacterial Retention of Membrane Filters Utilized for Liquid Filtration.

F 1094-87(1992) Methods for Microbiological Monitoring of Water Used for Processing Electron and Microelectronic Devices by Direct-Pressure Tap Sampling Valve and by the Pre-Sterilized Plastic Bag Method.

F 1095-88(1994) Method for Rapid Enumeration of Bacteria in Electronics Grade Purified Water Systems by Direct-Count Epifluorescence Microscopy.

F 1170-88(1993) Practice for Determining Performance of a Filter Medium Using Water and Siliceous Particles.

F 1213-89 Method for Determining the Particle Contamination and Media Migration Characteristics of Liquid Filters by Optical Microscopy.

F 1215-89 Method for Determining the Initial Efficiency of a Flatsheet Filter Medium in an Airflow Using Latex Spheres.

F 1226-89(1994) Method for Calibration of Liquid-Borne Particle Counters for Submicrometer Particle Sizing.

F 1228-89(1994) Method for Oxidizable (Organic) Carbon on Wafer Surfaces (by Persulfate).

F 1277-90 Method for Determination of Leachable Chloride in Packing and Gasketing Materials by Ion-Selective Electrode Technique.

F 1372-93 Method for Scanning Electron Microscope (SEM) Analysis of Metallic Surface Condition for Gas Distribution System Components.

F 1374-92 Method for Ionic/Organic Extractables of Internal Surfaces · IC/GC/FTIR for Gas Distribution System Components.

F 1375-92 Method for Energy Dispersive X-Ray Spectrometer (EDX) Analysis of Metallic Surface Condition for Gas Distribution System Components.

F 1376-92 Guide for Metallurgical Analysis for Gas Distribution System Components.

F 1394-92 Method for Determination of Particle Contribution from Gas Distribution System Valves.

F 1395 Methods for the Determination of Particle Contribution from Gas Distribution System Valves.

F 1396-93 Test Method for Determination of Oxygen Contribution by Gas Distribution System Components.

F 1397-93 Test Method for Determination of Moisture Contribution by Gas Distribution System Components.

F 1398-93 Method for Determination of Total Hydrocarbon Contribution by Gas Distribution System Components

F 1438-93 Method for Determination of Surface Roughness by Scanning Tunneling Microscopy for Gas Distribution System Components.

F 1471-93 Method for Evaluating the Air Cleaning Performance of a High-Efficiency Particulate Air-Filter System.

F 1500-94 Method for Quantitating Non-UV-Absorbing Nonvolatile Extractables from Microwave Susceptors Utilizing Solvents as Food Simulents.

F 1526-94a Method for Measuring Surface Metal Contamination on Silicon Wafers by Total Reflection X-Ray Fluorescence Spectroscopy.

F 1528-94 Method for Measuring Boron Contamination in Heavily Doped N-Type Silicon Substrates by Secondary Ion Mass Spectrometry.

4.3.3 IES Contamination Control Documents

Number Title

IES-RP-CC001.3 1993 Recommended Practice, HEPA and ULPA Filters.

IES-RP-CC-002-86 Jan. 1986 Recommended Practice, Laminar Flow Clean Air Devices.

IES-RP-CC003.2 1993 Garment System Considerations for Cleanrooms and Other Controlled Environments.

IES-RP-CC004.2 1992 Evaluating Wiping Materials Used in Cleanrooms and Other Controlled Environments.

IES-RP-CC005.2 April 1996 Cleanroom Gloves and Finger Cots Used in Cleanrooms and Other Controlled Environments.

IES-RP-CC006.2 1993 Testing Cleanrooms.

IES-RP-CC007.1 1992 Testing ULPA Filters.

IES-RP-CC-008-84 June 1984 Recommended Practice, Gas-Phase Adsorber Cells.

IES-RD-CC009.2 1993 Compendium of Standards, Practices, Methods, and Similar Documents Relating to Contamination Control.

IES-RD-CC011.2 1995 A Glossary of Terms and Definitions Relating to Contamination Control.

IES-RP-CC012.1 1992 Considerations in Cleanroom Design.

IES-RP-CC-013-86-T Aug. 1986 Recommended Practice, Equipment Calibration or Validation Procedures.

WG 014 Calibrating Particle Counters.

IES-RP-CC-015-87-T May 1987 Recommended Practice, Cleanroom Product and Support Equipment

IES-RP-CC016.1 1992 The Rate of Deposition of Nonvolatile Residue in Cleanrooms.

WG 017 Ultrapure Water: Contamination Analysis and Control.

IES-RP-CC018.2 1992 Cleanroom Housekeeping – Operating and Monitoring Procedures.

WG 019 Qualifications for Agencies and Personnel Engaged in the Testing and Certification of Cleanrooms and Clean Air Devices.

IES-RP-CC020.2 1996 Substrates and Forms for Documentation in Cleanrooms.

IES-RP-CC021.1 1994 Testing HEPA and ULPA Filter Media.

IES-RP-CC022.1 1992 Electrostatic Charge in Cleanrooms and Other Controlled Environments.

IES-RP-CC023.1 1993 Microorganisms in Cleanrooms.

IES-RP-CC024.1 1993 Measuring and Reporting Vibration in Microelectronic Facilities.

IES-RP-CC025. Swabs in Cleanrooms.

IES-RP-CC026. 1994 Cleanroom Operations.

WG 027 Personnel in Cleanrooms.

WG 028 Minienvironments.

WG 029 Automotive Paint Spray applications.

WG 030 Cleanroom Electrical Systems.

WG 031 Outgassisng Performance Criteria for Cleanroom Materials.

WG 1246 MIL-STD-1246 Revision.

4.3.4 Department of Defense (DOD) Standards

Number Title

AFM 88-4 Chapter 5 9 Sept. 1968 Facility Design and Construction, Criteria for Air Force Clean Facility Design and Construction

AFOSH STD 161-8 20 June 1978 Occupational Health Permissible Exposure Limits for Chemical Substances.

AGMC/MAQC-335C 22 Feb. 1989 Personnel Garments, Electrostatic Discharge (ESD) Requirements for the Protection of ESD Sensitive Items

DOD-E-8983-C 29 Dec. 1977 Electronic Equipment, Aerospace, Extended Space Environment, General Specification for

MIL--STD-1201C Ethyl Alcohol (Ethanol), Technical and Denatured Grades

MIL-A-83577B 1 Feb. 1988 Assemblies, moving Mechanical Parts, for Space and Launch Vehicles, General Specification for

MIL-B-81705B 15 Aug. 1974 Amendment 3 9 June 1983 Barrier Materials, Flexible, Electrostatic-Free, Heat Sealable.

MIL-C-170605C 13 Feb. 1980 Amendment 1 16 March 1982 Charcoal, Activated, Unimpregnated.

MIL-C-43122G Cloth, Sateen, Cotton, Flame Retardant Treated

MIL-F-51068F Amendment 2 5 April 1988 Filters, Particulate (High-Efficiency Fire Resistant)

MIL-F-51079D 14 March 1985 Filter Medium, Fire-Resistant, High-Efficiency.

MIL-F-51477 4 Oct. 1982 Filters, Particulate, High-Efficiency, Fire Resistant, Biological Use, General Specification for.

MIL-F-7179F 25 Sept. 1984 Amendment 1 20 May 1985 Finishes, Coatings, and Sealants for the Protection of Aerospace Weapons Systems

MIL-F-7179F 25 Sept. 1984 Amendment 1 20 May 1985 Finishes, Coatings, and Sealants for the Protection of Aerospace Weapons Systems.

MIL-HDBK-406 31 Oct. 1971 Notice 1, 1988 Contamination Control Technology, Cleaning Materials for Precision Precleaning and Use in Clean Rooms and Clean Work Stations.

MIL-HDBK-407 31 Jan. 1972 Change 1 20 Jan. 1984 Contamination Control Technology, Precision Cleaning Methods and Procedures.

MIL-HDBK-408 19 Jan. 1972 Contamination Control Technology, Microbial Deterioration in Electronics, Its Origin and Control.

MIL-HDBK-410 15 Oct. 1973 Contamination Control Technology, Logistic Protection of Precision Cleaned Materiel.

MIL-P-13949G 11 Feb. 1987 Amendment 1 26 Sept. 1988 Plastic Sheet, Laminated, Metal Clad (For Printed Circuit Boards), General Specification for.

MIL-P-26536D 27 July 1987 Military Specification, Propellant, Hydrazine

MIL-P-27401C 20 Jan. 1975 Propellant Pressurizing Agent, Nitrogen

MIL-P-27407A 28 Nov. 1978 Propellant Pressurizing Agent, Helium

MIL-S-83576 1 Nov. 1974 Solar Cell Arrays, Space Vehicle, Design and Testing, General Specification for.

MIL-STD-964(1) Manufacture and Packaging of Drugs, Pharmaceuticals and Biological Products

MIL-STD-989 Certification Requirements for JAN Semiconductor Devices

MIL--STD-1201C Ethyl Alcohol (Ethanol), Technical and Denatured Grades

MIL-STD-1241A 31 March 1967 Optical Terms and Definitions

MIL-STD-1246C 11 April 1994 Product Cleanliness Levels and Contamination Control Program

MIL-STD-1475 14 Feb. 1974 Contamination Control Technology, Packaging Protection of Precision Cleaned Materiel

MIL-STD-1540C 18 Sept. 1994 Test Requirements for Launch, Upper-Stage, and Space Vehicles.

MIL-STD-1586A Quality Program Requirements for Space and Launch Vehicles

MIL-STD-1695 13 Sept. 1977 Environments, Working, minimum Standards for

MIL-STD-1774 NOT 1 Process For Cleaning Hydrazine Systems and Components

MIL-STD-1775 NOT 1 Propellant, Hydrazine-Uns-Dimethylhydrazine 50/50 Blend

MIL-STD-182 28 May 1956 Notice 3 10 Feb. 1989 Filter Units, Protective Clothing, Gas-Mask Components and Related Products: Performance Test Methods.

MIL-STD-1844 Gas Chromatography Method for Determination of Trace Chlorinated Solvents in Hydraulic fluid

MIL-STD-282 28 May 1956 Filter Units, Protective Clothing, Gas-Mask Components and Related Products: Performance-Test Methods

MIL-STD-45662A 1 Aug. 1988 Calibration Systems Requirements

MIL-STD-785B Reliability Program for Systems and Equipment Development and Production

MIL-STD-810E 14 July 1989 Notice 1 9 Feb. 1990 Environmental Test Methods and Engineering Guidelines.

MIL-STD-980 Foreign Object Damage Prevention in Aerospace Products.

MIL-STD-1250A (Hot 62) Corrosion Prevention & Deterioration Control in Electronic Components.

MIL-STD-1543B (Hot 62) Reliability Program Requirements for Space and Launch Vehicles.

MIL-STD-1547A Electronic Parts, Materials and Processes for Space & Launch Vehicles.

MIL-STD-1586A Quality Program Requirements for Space and Launch Vehicles

MIL-T-43636B 10 June 1982 Thread, Aramid.

MIL-W-83575 1 March 1973 Wiring Harness, Space Vehicle, Design and Testing.

T.O. 00-25-203 1 Dec. 1972 Change 15 24 Oct. 1992 Contamination Control of Aerospace Facilities, U.S. Air Force.

T.O.00-20-14 30 June 1992 Change 1 15 Dec. 1993 Technical Manual, Air Force Metrology and Calibration Program.

4.3.5 European Space Agency (ESA) Documents

Number Title

ESRO TN-110 Feb. 1971 Screening of Space Materials with the Micro-VCM Weight-Loss Test. A. Zwaal & J. Dauphin, ESTEC, & A. A. Roldan, INTA, Madrid, Spain

PSS-01-0 Issue 1, May 1981 Basic Requirements for Product Assurance of ESA Spacecraft and Associated Equipment.

PSS-01-10 Issue 1, May 1981 Product Assurance Management and Audit Systems for ESA Spacecraft and Associated Equipment.

PSS-01-11 Issue 1, March 1989 Configuration Management and Control for ESA Systems.

PSS-01-20 Issue 2, Feb. 1991 Quality Assurance Requirements for ESA Space Systems.

PSS-01-101 Issue 1, Feb. 1983 Software Quality Assurance Plan.

PSS-01-201 Issue 1, Aug. 1983 Contamination and Cleanliness Control.

PSS-01-202 Issue 1, June 1983 Preservation, Storage, Handling, and Transportation of Spacecraft Hardware.

PSS-01-203 Issue 1, Aug. 1983 Quality Assurances of Test Houses for ESA Spacecraft and Associated Equipment.

PSS-01-204 Issue 1 Sept. 1984 Particulate Contamination Control in Clean Rooms by Particle Fall-Out Measurements.

PSS-01-21 Issue 2, April 1991 Software Product Assurance Requirements for ESA Space Systems.

PSS-01-30 Issue 2, March 1992 Reliability Assurance for ESA Space Systems.

PSS-01-40 Issue 2, Sept. 1988 System Safety Requirements for ESA Space Systems and Associated Equipment.

PSS-01-50 Issue 1, Nov. 1991 Maintainability Requirements for ESA Space Systems.

PSS-01-60 Issue 2, Nov. 1988 Component Selection Procurement and Control for ESA Space Systems.

PSS-01-301 Issue 2, April 1992 Derating Requirements Applicable to Electronic, Electrical, and Electro-Mechanical Components.

PSS-01-401 Issue 1, March 1989 ESA Fracture Control Requirements.

PSS-01-603 Issue 2, June 1985 ESA Preferred Parts List (PPL).

PSS-01-604 Issue 1, Oct. 1988 Generic Specification for Silicon Solar Cells.

PSS-01-605 Issue 1, May 1990 Capability Approval Programme for Hermetic Thick Film Hybrid Microcircuits.

PSS-01-606 Issue 1, July 1986 The Capability Approval Programme for Hermetic Thick Film Hybrid Microcircuits.

PSS-01-607 Issue 1, Nov. 1990 Checklist for Thick-Film Hybrid Microcircuits Manufacturer and Line Survey.

PSS-01-608 Issue 2, April 1987 Generic Specification for Hybrid Microcircuits.

PSS-01-609 Issue 1, May 1993 The Radiation Design Handbook.

PSS-01-610 Issue 1, Nov. 1991 Design Guidelines for Capability Approval of Film Hybrid Microcircuits and Microwave Hybrid :Integrated Circuits.

PSS-01-611 Issue 1, Nov. 1990 Checklist for Thin-Film Hybrid Microcircuits Manufacturer and Line Survey.

PSS-01-612 Issue 1, Nov. 1990 Capability Approval Programme for Microwave Hybrid Integrated Circuits (MMICs).

PSS-01-70 Issue 4, Jan. 1994 Material, Mechanical-Part and Process Selection and Quality Control for ESA Space Systems and Associated Equipment.

PSS-01-700 Issue 2, Aug. 1993 The Technical Reporting and Approval Procedure for Materials, Mechanical Parts and Processes.

PSS-01-701 Issue 1, Rev. 3 Jan. 1994 Data for Selection of Space Materials.

PSS-01-702 Issue 1, March 1983 A Thermal Vacuum Test for the Screening of Space Materials.

PSS-01-703 Issue 1, Oct. 1982 The Black Anodising of Aluminium With Inorganic Dyes.

PSS-01-704 Issue 1, Aug. 1982 A Thermal Cycling Test for the Screening of Space Materials and Processes.

PSS-01-705 Issue 1, Oct. 1982 The Detection of Organic Contamination of Surfaces by Infrared Spectroscopy.

PSS-01-706 Issue 1, March 1983 The Particle and UV Radiation Testing of Space Materials.

PSS-01-707 Issue 1, Feb. 1984 The Evaluation and Approval of Automatic Machine Wave Soldering.

PSS-01-708 Issue 1, March 1985 The Manual Soldering of High Reliability Electrical Connections.

PSS-01-709 Issue 1, July 1984 Measurement of Thermo-Optical Properties of Thermo Control Materials.

PSS-01-710 Issue 1, Oct. 1985 The Qualification and Procurement of Two Sided Printed Circuit Boards (Gold Plated or Tin/Lead Finish).

PSS-01-711 Issue 1, Oct. 1982 Product Assurance Requirements for Micro-VCM-Apparatus and Associated Equipment.

PSS-01-712 Issue 1, Aug. 1983 The Oil Impregnation of Phenolic Resin Based Materials Used in the Fabrication of Ball Bearing Cages.

PSS-01-713 Issue 1, Oct. 1982 Measurement of the Peal and Pull-Off Strength of Coatings and Finishes with Pressure Sensitive Tape.

PSS-01-716 Issue 1, Oct. 1982 The Listing and Approval Procedure for Materials and Processes.

PSS-01-717 Issue 1 The Qualification and Procurement of Multilayer Printed Circuit Boards.

PSS-01-718 Issue 1, Oct. 1987 The Preparation and Mounting of RF Coaxial Cables.

PSS-01-720 Issue 1, July 1985 Determination of the Susceptibility of Silver Plated Copper Wire/Cables to Red Plague Corrosion.

PSS-01-721 Issue 2, April 1992 Flammability Testing for the Screening of Space Materials.

PSS-01-722 Issue 2, Dec. 1990 The Control of Limited Life Materials.

PSS-01-725 Issue 1, Dec. 1982 The Application of the Black Paint Chemglaze Z306.

PSS-01-726 Issue 2, Dec. 1990 The Crimping of High Reliability Electrical Connections.

PSS-01-727 Issue 1, Oct. 1982 The Cleaning of Eccosorb AN Foam.

PSS-01-728 Issue 2, March 1991 The Repair and Modification of Printed-Circuit Board Assemblies for Space Use.

PSS-01-729 Issue 1, Feb. 1989 The Determination of Offgassing Products From Materials and Assembled Articles to be used in Manned Space Vehicle Crew Compartment.

PSS-01-730 Issue 1, March 1991 The Wire Wrapping of High Reliability Electrical Connections.

PSS-01-732 Issue 1, Dec. 1982 The Cleaning of Gude-Space D96 Tape.

PSS-01-733 Issue 1, Oct. 1982 The Application of the Thermal Control Paint Pyrolac PSG120FG.

PSS-01-734 Issue 1, Feb. 1983 The Application of the Black Electrically Conductive Coating Chemglaze H322.

PSS-01-735 Issue 1, Dec. 1982 The Application of the Black Electrically Conductive Coating Chemglaze L300.

PSS-01-736 Issue 1, May 1981 Materials Selection for Controlling Stress Corrosion Cracking.

PSS-01-737 Issue 1, Dept. 1981 Determination of Susceptibility of Metals to Stress Corrosion Cracking.

PSS-01-738 Issue 1, March 1991 High-Reliability Soldering for Surface-Mount and Mixed-Technology Printed Circuit Boards.

PSS-01-746 Issue 1, June 1993 General Requirements for Aerospace Fasteners Materials.

PSS-01-748 Issue 1, March 1992 Requirements for ESA Approved Skills Training and Certification (Electronic Assembly Techniques).

PSS-07 (QRM-01) Issue 5, July 1979 Guidelines for Space Materials Selection.

PSS-09/QRM-02T Issue 1, Jan. 1972 A Screening Test Method Employing a Thermal Vacuum for the Selection of Materials to be Used in Space.

PSS-18/QRM-13T Issue 1, Sept. 1975 Testing the Peel or Pull-Off Strength of Coatings and Finishes by Means of Pressure-Sensitive Tapes.

PSS-19/QR-16 Issue 2, Jan. 1978 Qualification of Materials and Materials Lists Applicable to Space Projects.

PSS-26 (QRM-21T) Issue 2, Sept. 1980 Flammability Testing.

PSS-28/QRM-22 Issue 1, Dec. 1976 Guidelines for the Control of Limited-Life Materials.

PSS-51 (QRA-23) Issue 1, May 1979 Guidelines for Spacecraft Cleanliness Control.

PSS-52 (QRM-32P) Issue 1, April 1979 Method of Cleaning Gude-Space D96.

PSS-54 (QRC-01) Issue 1, Nov. 1979 Requirements for a Component Quality-Control and Procurement Programme.

4.3.6 Society of Automotive Engineers CC Standards

Number Title

ARP 598B-86 (1991) The Determination of Particulate Contamination in Liquids by the Particle Count Method.

ARP 743A-66 (1991) Procedure for the Determination of Particulate Contamination of Air in Dust Controlled Spaces by the Particle Count Method.

ARP 785-63 (1991) Procedure for the Determination of Particulate Contamination in Hydraulic Fluids by the Control Filter Gravimetric Procedure.

ARP 1192B-87 (1991) Procedure for Calibration and Verification of Liquid-Borne Particle Counter.

ARP 4252-89 (1989) Instrumental Methods of Determining Surface Cleanliness.

4.3.7 Federal Contamination Control Standards

Number Title

A-A-50195 Thread, Aramid

F-F-310 29 Oct. 1957 Amendment 3 16 May 1962 Filter, Air Conditioning, (Viscous-Impingement Type, Replaceable).

FED-STD-101C

FED STD-141C 24 Jan. 1986 Paint, Varnish, Lacquer and Related Materials: Methods of Inspection, Sampling and Testing.

FED-STD-191A 20 July 1978 Textile Test Methods.

FED-STD-209E 11 Sept. 1992 Change Notice 2 15 Dec. 1994 Airborne Particulate Cleanliness Classes in Cleanrooms and Clean Zones.

FED-STD-751A 25 Jan. 1965 Stitches, Seams, and Stitchings.

O-A-51 Acetone, ACS Reagent

TT-I-735 Isopropyl Alcohol