ASTM E1559-09(2016)

Standard Test Method for Contamination Outgassing Characteristics of Spacecraft Materials

ABSTRACT
This test method covers a technique for generating data to characterize the kinetics of the release of outgassing products from spacecraft materials. This technique will determine both the total mass flux evolved by a material when exposed to a vacuum environment and the deposition of this flux on surfaces held at various specified temperatures. The quartz crystal microbalances used in this test method provide a sensitive technique for measuring very small quantities of deposited mass. There are two test methods in this standard: Test Method A and Test Method B. The test apparatus shall consists of four main subsystems: a vacuum chamber, a temperature control system, internal configuration, and a data acquisition system. A test procedure for collecting data and a test method for processing and presenting the collected data are included.
SCOPE
1.1 This test method covers a technique for generating data to characterize the kinetics of the release of outgassing products from materials. This technique will determine both the total mass flux evolved by a material when exposed to a vacuum environment and the deposition of this flux on surfaces held at various specified temperatures.  
1.2 This test method describes the test apparatus and related operating procedures for evaluating the total mass flux that is evolved from a material being subjected to temperatures that are between 298 and 398 K. Pressures external to the sample effusion cell are less than 7 × 10−3 Pa (5 × 10−5 torr). Deposition rates are measured during material outgassing tests. A test procedure for collecting data and a test method for processing and presenting the collected data are included.  
1.3 This test method can be used to produce the data necessary to support mathematical models used for the prediction of molecular contaminant generation, migration, and deposition.  
1.4 All types of organic, polymeric, and inorganic materials can be tested. These include polymer potting compounds, foams, elastomers, films, tapes, insulations, shrink tubing, adhesives, coatings, fabrics, tie cords, and lubricants.  
1.5 There are two test methods in this standard. Test Method A uses standardized specimen and collector temperatures. Test Method B allows the flexibility of user-specified specimen and collector temperatures, material and test geometry, and user-specified QCMs.  
1.6 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 30-Sep-2016
• ICS: 49.025.01 - Materials for aerospace construction in general
• Technical Committee: E21 - Space Simulation and Applications of Space Technology
• Drafting Committee: E21.05 - Contamination

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E1559 − 09 (Reapproved 2016)
Standard Test Method for
Contamination Outgassing Characteristics of Spacecraft
Materials
This standard is issued under the fixed designation E1559; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
1.1 This test method covers a technique for generating data
to characterize the kinetics of the release of outgassing
2. Referenced Documents
products from materials. This technique will determine both
2.1 ASTM Standards:
the total mass flux evolved by a material when exposed to a
E595Test Method for Total Mass Loss and Collected Vola-
vacuumenvironmentandthedepositionofthisfluxonsurfaces
tile Condensable Materials from Outgassing in a Vacuum
held at various specified temperatures.
Environment
1.2 Thistestmethoddescribesthetestapparatusandrelated
2.2 Military Standard:
operating procedures for evaluating the total mass flux that is
MIL-P-27401DPropellant Pressurizing Agent, Nitrogen
evolved from a material being subjected to temperatures that
2.3 Other Standard:
are between 298 and 398 K. Pressures external to the sample
−3 −5
SMC-TR-95–28 Non-Volatile Residue Solvent
effusion cell are less than7×10 Pa (5 × 10 torr).
Replacement, Report No. TR95 (5448)-1
Depositionratesaremeasuredduringmaterialoutgassingtests.
A test procedure for collecting data and a test method for
3. Terminology
processing and presenting the collected data are included.
3.1 Definitions:
1.3 This test method can be used to produce the data
3.1.1 AT cut crystal, n—a quartz crystal orientation that
necessary to support mathematical models used for the predic-
minimizes the temperature coefficient (frequency change ver-
tion of molecular contaminant generation, migration, and
sus temperature) over a wide range of temperature.
deposition.
3.1.2 azeotropic mixture, n—a solution of two or more
1.4 All types of organic, polymeric, and inorganic materials
liquids, the composition of which does not change upon
can be tested. These include polymer potting compounds,
distillation. Also known as azeotrope.
foams, elastomers, films, tapes, insulations, shrink tubing,
3.1.3 collected volatile condensable material, CVCM,
adhesives, coatings, fabrics, tie cords, and lubricants.
n—(fromTestMethodE595).Thequantityofoutgassedmatter
1.5 Therearetwotestmethodsinthisstandard.TestMethod
from a test specimen that condenses on a collector maintained
Auses standardized specimen and collector temperatures. Test
at a specific constant temperature for a specified time and
Method B allows the flexibility of user-specified specimen and
measured before and after the test outside the chamber.
collector temperatures, material and test geometry, and user-
3.1.3.1 Discussion—CVCMisspecifictoTestMethodE595
specified QCMs.
and is calculated from the condensate mass determined from
1.6 The values stated in SI units are to be regarded as the
thedifferenceinmassofthecollectorplatebeforeandafterthe
standard. The values given in parentheses are for information
test in a controlled laboratory environment. CVCM is ex-
only.
pressed as a percentage of the initial specimen mass.The view
1.7 This standard does not purport to address all of the
factor is not considered; so all the VCM outgassing from the
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
This test method is under the jurisdiction of ASTM Committee E21 on Space Standards volume information, refer to the standard’s Document Summary page on
Simulation andApplications of SpaceTechnology and is the direct responsibility of the ASTM website.
Subcommittee E21.05 on Contamination. AvailablefromStandardizationDocumentsOrderDesk,Bldg.4SectionD,700
Current edition approved Oct. 1, 2016. Published October 2016. Originally Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
approved in 1993. Last previous edition approved in 2009 as E1559–09. DOI: Available fromTheAerospace Corporation, P.O. Box 92957, LosAngeles, CA
10.1520/E1559-09R16. 90009–2957, http://www.aero.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1559 − 09 (2016)
sample may not be collected. Care should be used in compar- can be normalized with respect to the sample surface area and
ing the CVCM from Test Method E595 with VCM from this be expresed as µg/cm .
test method.
3.1.14.1 in-situ TML, n—calculated from the mass depos-
3.1.4 differential scanning calorimetry, DSC, n—a tech-
ited on a cryogenically cooled QCM and the view factor from
nique in which the difference in energy inputs into a substance
the effusion cell orifice to the QCM.
and a reference material is measured as a function of tempera-
3.1.14.2 Discussion—In-situ TML is a function of the out-
turewhilethesubstanceandreferencematerialaresubjectedto
gassing test time and is expressed as a percentage of the initial
a controlled-temperature program.
specimen mass. This is not necessarily the same as the TML
3.1.5 effusion cell, n—a container, placed in a vacuum, in
determined by Test Method E595.
which a sample of material can be placed and heated to some
3.1.14.3 ex-situ TML, n—total mass of material outgassed
specified temperature.
from a test specimen that is maintained at a specified constant
temperature and operating pressure for a specified time and
3.1.5.1 Discussion—The container has a cylindrical orifice
measured outside the test chamber.
at one end so that evolving gases exit the cell in a controlled
manner. The effusion cell dimensions and orifice size are
3.1.14.4 Discussion—Ex-situ TML is calculated from the
specified such that there is free molecular flow of the evolving
mass of the specimen as measured before and after the test in
gasses and a predictable molecular flux from the orifice.
a controlled laboratory environment and is expressed as a
3.1.6 mass flux, n—the mass of molecular flux.
percentage of the initial specimen mass. (From Test Method
−2 −1
E595.)
3.1.7 molecular flux (molecules·cm ·s ), n—the number
ofgasmoleculescrossingaspecifiedplaneinunittimeperunit 3.1.15 total outgassing rate, n—the net rate of mass loss
from a material sample as a result of outgassing. Total
area.
outgassing rate can be normalized per unit sample surface area
3.1.8 nonvolatile residue, NVR, n—the quantity of residual
−2 −1
and expressed as g·cm ·s or it can be normalized per unit
molecular and particulate matter remaining following the
−1 −1
initial sample mass and expressed as g·g ·s .
filtration of a solvent containing contaminants and evaporation
3.1.16 volatile condensable material, VCM, n—the matter
of the solvent at a specified temperature.
that outgasses from a material and condenses on a collector
3.1.9 outgassing, n—the evolution of gas from a material,
surface that is at a specified temperature.
usually in a vacuum. Outgassing also occurs in a higher
pressure environment.
3.1.16.1 Discussion—For this test method, this is the quan-
tityofoutgassedmatterfromatestspecimenthatcondenseson
3.1.10 quartz crystal microbalance, QCM, n—a device for
surfaces maintained at QT2 or QT3. The VCM is calculated
measuring small quantities of mass using the properties of a
from the mass deposited on QCM2 or QCM3 and the view
quartz crystal oscillator.
factor from the effusion cell orifice to the QCMs. VCM is a
3.1.10.1 Discussion—The resonant frequency of a quartz
function of the outgassing test time and is expressed as a
crystal oscillator is inversely proportional to the thickness of
percentage of the initial specimen mass. In addition,VCM can
the crystal. When the mass of a uniform deposit is small
be normalized with respect to the sample surface area and be
relative to the mass of the crystal, the change in frequency is
expressed as µg/cm . This is not the same as CVCM as
proportional to the mass of the deposit.
determined by Test Method E595 (see 3.1.3).
3.1.11 QCM thermogravimetric analysis, QTGA, n—a tech-
3.2 Acronyms:
nique in which a QCM is heated at a constant rate to remove
3.2.1 GN,n—gaseous nitrogen.
a collected deposit.
3.2.2 LN,n—liquid nitrogen.
3.1.11.1 Discussion—This is performed to determine the
3.2.3 MAPTIS, n—Materials and Process Technical Infor-
evaporation characteristics of the species in the deposit. The mation Service.
mass of the deposit on the QCM is recorded as a function of
3.3 Definitions of Terms Specific to This Standard:
time or temperature.
3.3.1 QCM1—the QCM that is operating at the temperature
3.1.12 residual gas analyzer, RGA, n—a mass spectrometer
TQ1 (cryogenic) for measuring the total outgassing rate.
mounted inside or attached to a vacuum chamber.
3.3.2 QCM2 and QCM3—the QCMs that are operating at
3.1.12.1 Discussion—RGA can be used for identifying temperatures TQ2 and TQ3 for the measurement of the
gases in the vacuum chamber. deposition of outgassing matter.
−2 −1
3.1.13 totalmassflux(g·cm ·s ),n—thesummationofthe
mass from all molecular species crossing a specified plane in 4. Summary of Test Method
unit time per unit area.
4.1 The test apparatus described in this test method is
3.1.14 total mass loss, TML, n—total mass of material designed to measure outgassing rate data that can be used to
outgassedfromatestspecimenthatismaintainedataspecified develop kinetic expressions for use in models that predict the
constant temperature and operating pressure for a specified evolution of molecular contaminants and the migration and
time and measured within the test chamber. TML is expressed deposition of these contaminants on spacecraft surfaces. Ma-
as a percentage of the initial specimen mass. In addition,TML terialsthatcontainvolatilespeciesthatwillbeoutgassedunder
E1559 − 09 (2016)
the temperature and vacuum conditions of this test method can sample can be properly compared with that of other samples.
be characterized.The quartz crystal microbalances used in this The outgassing rate of the material will, in general, be
test method provide a sensitive technique for measuring very determined by its composition, processing history, and envi-
small quantities of deposited mass. In addition to providing ronmentalconditioningbeforethetest.Alltestsampleprocess-
data for kinetic expressions, the reduced data can be used to ingshouldberepresentativeofnormalmaterialprocessingand
compare the outgassing behavior of different materials for usage.All materials are environmentally conditioned to speci-
material selection purposes. fied conditions. However, samples may be subjected to envi-
ronmental conditions that are expected during actual use. Test
4.2 Therearetwotestmethodsinthisstandard.TestMethod
sampleprocessingandconditioninghistoryshallbeincludedin
Aisthestandardprocedureusingprescribedconfigurationsand
the test report.
temperatures. Test Method B allows for the use of spacecraft
4.8 Because outgassing of all materials is, to some extent,
systemspecifictemperatures,configurations,andQCMcollec-
diffusion rate controlled, the outgassing rate of a test sample
tor surface finishes.
depends on the distance from the sample interior to a free
4.3 The measurements are made by placing the material
surface. Hence, the geometry of a test sample must be
sample in an effusion cell so that the outgassing flux leaving
controlled in a specified manner to permit meaningful inter-
thecellorificewillimpingeonthreeQCMswhicharearranged
pretation of the data. When possible, the sample geometry
toviewtheorifice.AfourthQCMisoptional.Theeffusioncell
should be in the specified configuration to simplify modeling.
is held at a constant temperature in the high vacuum chamber
However, the material sample can be made with the same
and has a small orifice directed at the QCMs. The QCMs are
geometry as it would have in an actual application.
controlledtoselectedtemperatures.Thetotaloutgassingrateis
determined from the collection rate on a cryocooled QCM.At 5. Test Apparatus
the end of the isothermal test, the QCMs are heated in a
5.1 Description—The test apparatus consists of four main
controlled manner to determine the evaporation characteristics
subsystems: a vacuum chamber, a temperature control system,
of the deposits.
internal configuration, and a data acquisition system. Fig. 1 is
a schematic of the systems, and Fig. 2 shows the vacuum
4.4 The effusion cell is loaded from the vacuum interlock
chamber and internal configuration.
chamber to the main test chamber and is positioned at a fixed
distance and angle with respect to the QCM surfaces. The
5.2 Vacuum Chamber—The principal components of the
effusion cell is temperature controlled to provide constant and
vacuum chamber are the main test chamber, the vacuum
uniform heating of the sample.The vacuum interlock chamber
interlock chamber, and cryogenic shrouds (for example, LN ).
is a device that enables the expedient introduction of the test
A high-vacuum gate valve is used to isolate the main test
sample into the high vacuum of the main test chamber. Use of
chamber from the interlock chamber. This allows the effusion
theinterlockchambertoloadandunloadsamplespreventsloss
celltobewithdrawnorinsertedintothemainchamberwithout
of vacuum in the main chamber and diminishes the need to
the loss of high vacuum in the main chamber. High-vacuum
pump it down before each test.
electrical and mechanical feedthroughs are used to access the
interior of the chamber.
4.5 The QCM collection method for measuring the total
outgassing rate from a sample is an indirect technique. Rather
5.3 Internal Configuration—Three quartz crystal microbal-
than directly measuring sample mass loss, the basic measure- ances(QCMs)(afourthQCMisoptional),aneffusioncell,and
ment is the fraction of the flux that condenses on the cryogeni-
cryogenic heat sinks in the chamber are the principal compo-
cally cooled QCM collector at a point in the outgassing flow nents. The cryogenic heat sinks are used to ground the QCMs
field. That point in the flow field is defined as the geometric
thermally and to cool shrouds which surround the effusion cell
location of the QCM relative to the effusion cell orifice, which and QCMs. The cold shrouds limit molecular contaminant
isatafixedlocation.Todeterminetherateofsamplemassloss
fluxestotheline-of-sightoutgassingfluxfromtheeffusionce
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E1559 − 09 E1559 − 09 (Reapproved 2016)
Standard Test Method for
Contamination Outgassing Characteristics of Spacecraft
Materials
This standard is issued under the fixed designation E1559; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers a technique for generating data to characterize the kinetics of the release of outgassing products
from materials. This technique will determine both the total mass flux evolved by a material when exposed to a vacuum
environment and the deposition of this flux on surfaces held at various specified temperatures.
1.2 This test method describes the test apparatus and related operating procedures for evaluating the total mass flux that is
evolved from a material being subjected to temperatures that are between 298 and 398 K. Pressures external to the sample effusion
−3 −5
cell are less than 7 × 10 Pa (5 × 10 torr). Deposition rates are measured during material outgassing tests. A test procedure for
collecting data and a test method for processing and presenting the collected data are included.
1.3 This test method can be used to produce the data necessary to support mathematical models used for the prediction of
molecular contaminant generation, migration, and deposition.
1.4 All types of organic, polymeric, and inorganic materials can be tested. These include polymer potting compounds, foams,
elastomers, films, tapes, insulations, shrink tubing, adhesives, coatings, fabrics, tie cords, and lubricants.
1.5 There are two test methods in this standard. Test Method A uses standardized specimen and collector temperatures. Test
Method B allows the flexibility of user-specified specimen and collector temperatures, material and test geometry, and
user-specified QCMs.
1.6 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
E595 Test Method for Total Mass Loss and Collected Volatile Condensable Materials from Outgassing in a Vacuum
Environment
2.2 Military Standard:
MIL-P-27401D Propellant Pressurizing Agent, Nitrogen
2.3 Other Standard:
SMC-TR-95–28 Non-Volatile Residue Solvent Replacement, Report No. TR95 (5448)-1
3. Terminology
3.1 Definitions:
3.1.1 AT cut crystal, n—a quartz crystal orientation that minimizes the temperature coefficient (frequency change versus
temperature) over a wide range of temperature.
This test method is under the jurisdiction of ASTM Committee E21 on Space Simulation and Applications of Space Technology and is the direct responsibility of
Subcommittee E21.05 on Contamination.
Current edition approved April 1, 2009Oct. 1, 2016. Published May 2009October 2016. Originally approved in 1993. Last previous edition approved in 20032009 as
E1559 – 03.E1559 – 09. DOI: 10.1520/E1559-09.10.1520/E1559-09R16.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700 Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
Available from The Aerospace Corporation, P.O. Box 92957, Los Angeles, CA 90009–2957, http://www.aero.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1559 − 09 (2016)
3.1.2 azeotropic mixture, n—a solution of two or more liquids, the composition of which does not change upon distillation. Also
known as azeotrope.
3.1.3 collected volatile condensable material, CVCM, n—(from Test Method E595). The quantity of outgassed matter from a
test specimen that condenses on a collector maintained at a specific constant temperature for a specified time and measured before
and after the test outside the chamber.
3.1.3.1 Discussion—
CVCM is specific to Test Method E595 and is calculated from the condensate mass determined from the difference in mass of the
collector plate before and after the test in a controlled laboratory environment. CVCM is expressed as a percentage of the initial
specimen mass. The view factor is not considered; so all the VCM outgassing from the sample may not be collected. Care should
be used in comparing the CVCM from Test Method E595 with VCM from this test method.
3.1.4 differential scanning calorimetry, DSC, n—a technique in which the difference in energy inputs into a substance and a
reference material is measured as a function of temperature while the substance and reference material are subjected to a
controlled-temperature program.
3.1.5 effusion cell, n—a container, placed in a vacuum, in which a sample of material can be placed and heated to some specified
temperature.
3.1.5.1 Discussion—
The container has a cylindrical orifice at one end so that evolving gases exit the cell in a controlled manner. The effusion cell
dimensions and orifice size are specified such that there is free molecular flow of the evolving gasses and a predictable molecular
flux from the orifice.
3.1.6 mass flux, n—the mass of molecular flux.
−2 −1
3.1.7 molecular flux (molecules·cm ·s ), n—the number of gas molecules crossing a specified plane in unit time per unit area.
3.1.8 nonvolatile residue, NVR, n—the quantity of residual molecular and particulate matter remaining following the filtration
of a solvent containing contaminants and evaporation of the solvent at a specified temperature.
3.1.9 outgassing, n—the evolution of gas from a material, usually in a vacuum. Outgassing also occurs in a higher pressure
environment.
3.1.10 quartz crystal microbalance, QCM, n—a device for measuring small quantities of mass using the properties of a quartz
crystal oscillator.
3.1.10.1 Discussion—
The resonant frequency of a quartz crystal oscillator is inversely proportional to the thickness of the crystal. When the mass of a
uniform deposit is small relative to the mass of the crystal, the change in frequency is proportional to the mass of the deposit.
3.1.11 QCM thermogravimetric analysis, QTGA, n—a technique in which a QCM is heated at a constant rate to remove a
collected deposit.
3.1.11.1 Discussion—
This is performed to determine the evaporation characteristics of the species in the deposit. The mass of the deposit on the QCM
is recorded as a function of time or temperature.
3.1.12 residual gas analyzer, RGA, n—a mass spectrometer mounted inside or attached to a vacuum chamber.
3.1.12.1 Discussion—
RGA can be used for identifying gases in the vacuum chamber.
−2 −1
3.1.13 total mass flux (g·cm ·s ), n—the summation of the mass from all molecular species crossing a specified plane in unit
time per unit area.
3.1.14 total mass loss, TML, n—total mass of material outgassed from a test specimen that is maintained at a specified constant
temperature and operating pressure for a specified time and measured within the test chamber. TML is expressed as a percentage
of the initial specimen mass. In addition, TML can be normalized with respect to the sample surface area and be expresed as
μg/cm .
E1559 − 09 (2016)
3.1.14.1 in-situ TML, n—calculated from the mass deposited on a cryogenically cooled QCM and the view factor from the
effusion cell orifice to the QCM.
3.1.14.2 Discussion—
In-situ TML is a function of the outgassing test time and is expressed as a percentage of the initial specimen mass. This is not
necessarily the same as the TML determined by Test Method E595.
3.1.14.3 ex-situ TML, n—total mass of material outgassed from a test specimen that is maintained at a specified constant
temperature and operating pressure for a specified time and measured outside the test chamber.
3.1.14.4 Discussion—
Ex-situ TML is calculated from the mass of the specimen as measured before and after the test in a controlled laboratory
environment and is expressed as a percentage of the initial specimen mass. (From Test Method E595.)
3.1.15 total outgassing rate, n—the net rate of mass loss from a material sample as a result of outgassing. Total outgassing rate
−2 −1
can be normalized per unit sample surface area and expressed as g·cm ·s or it can be normalized per unit initial sample mass
−1 −1
and expressed as g·g ·s .
3.1.16 volatile condensable material, VCM, n—the matter that outgasses from a material and condenses on a collector surface
that is at a specified temperature.
3.1.16.1 Discussion—
For this test method, this is the quantity of outgassed matter from a test specimen that condenses on surfaces maintained at QT2
or QT3. The VCM is calculated from the mass deposited on QCM2 or QCM3 and the view factor from the effusion cell orifice
to the QCMs. VCM is a function of the outgassing test time and is expressed as a percentage of the initial specimen mass. In
addition, VCM can be normalized with respect to the sample surface area and be expressed as μg/cm . This is not the same as
CVCM as determined by Test Method E595 (see 3.1.3).
3.2 Acronyms:
3.2.1 GN , n—gaseous nitrogen.
3.2.2 LN , n—liquid nitrogen.
3.2.3 MAPTIS, n—Materials and Process Technical Information Service.
3.3 Definitions of Terms Specific to This Standard:
3.3.1 QCM1—the QCM that is operating at the temperature TQ1 (cryogenic) for measuring the total outgassing rate.
3.3.2 QCM2 and QCM3—the QCMs that are operating at temperatures TQ2 and TQ3 for the measurement of the deposition
of outgassing matter.
4. Summary of Test Method
4.1 The test apparatus described in this test method is designed to measure outgassing rate data that can be used to develop
kinetic expressions for use in models that predict the evolution of molecular contaminants and the migration and deposition of
these contaminants on spacecraft surfaces. Materials that contain volatile species that will be outgassed under the temperature and
vacuum conditions of this test method can be characterized. The quartz crystal microbalances used in this test method provide a
sensitive technique for measuring very small quantities of deposited mass. In addition to providing data for kinetic expressions,
the reduced data can be used to compare the outgassing behavior of different materials for material selection purposes.
4.2 There are two test methods in this standard. Test Method A is the standard procedure using prescribed configurations and
temperatures. Test Method B allows for the use of spacecraft system specific temperatures, configurations, and QCM collector
surface finishes.
4.3 The measurements are made by placing the material sample in an effusion cell so that the outgassing flux leaving the cell
orifice will impinge on three QCMs which are arranged to view the orifice. A fourth QCM is optional. The effusion cell is held
at a constant temperature in the high vacuum chamber and has a small orifice directed at the QCMs. The QCMs are controlled to
selected temperatures. The total outgassing rate is determined from the collection rate on a cryocooled QCM. At the end of the
isothermal test, the QCMs are heated in a controlled manner to determine the evaporation characteristics of the deposits.
4.4 The effusion cell is loaded from the vacuum interlock chamber to the main test chamber and is positioned at a fixed distance
and angle with respect to the QCM surfaces. The effusion cell is temperature controlled to provide constant and uniform heating
of the sample. The vacuum interlock chamber is a device that enables the expedient introduction of the test sample into the high
E1559 − 09 (2016)
vacuum of the main test chamber. Use of the interlock chamber to load and unload samples prevents loss of vacuum in the main
chamber and diminishes the need to pump it down before each test.
4.5 The QCM collection method for measuring the total outgassing rate from a sample is an indirect technique. Rather than
directly measuring sample mass loss, the basic measurement is the fraction of the flux that condenses on the cryogenically cooled
QCM collector at a point in the outgassing flow field. That point in the flow field is defined as the geometric location of the QCM
relative to the effusion cell orifice, which is at a fixed location. To determine the rate of sample mass loss from the rate of QCM
collection, the view factor from the QCM to the effusion cell orifice and the angular distribution of flux leaving the orifice must
be determined. This relationship can be calculated from the apparatus geometry and the effusion cell orifice dimensions.
4.6 A QCM thermogravimetric analysis (QTGA) test is also included in the procedure. This technique heats the QCMs at a
constant rate to measure evaporation characteristics of the deposits collected on the QCMs. The QTGA also provides an effective
means to clean the QCM surfaces before subsequent tests.
4.7 It is critical to the posttest analysis that the material sample be completely described and specified, so that the outgassing
characteristics can be applied to the material when used on a spacecraft. It is also necessary so that any material sample can be
properly compared with that of other samples. The outgassing rate of the material will, in general, be determined by its
composition, processing history, and environmental conditioning before the test. All test sample processing should be
representative of normal material processing and usage. All materials are environmentally conditioned to specified conditions.
However, samples may be subjected to environmental conditions that are expected during actual use. Test sample processing and
conditioning history shall be included in the test report.
4.8 Because outgassing of all materials is, to some extent, diffusion rate controlled, the outgassing rate of a test sample depends
on the distance from the sample interior to a free surface. Hence, the geometry of a test sample must be controlle
...