ASTM E1559-00

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: E 1559 – 00
Standard Test Method for
Contamination Outgassing Characteristics of Spacecraft
Materials
This standard is issued under the fixed designation E 1559; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope ASTM Test Methods
E 595 Test Method for Total Mass Loss and Collected
1.1 This test method covers a technique for generating data
Volatile Condensable Materials from Outgassing in a
to characterize the kinetics of the release of outgassing
Vacuum Environment
products from materials. This technique will determine both
IEEE/ASTM SI 10-1997 Standard for Use of the Interna-
the total mass flux evolved by a material when exposed to a
tional System of Units (SI): The Modern Metric System
vacuum environment and the deposition of this flux on surfaces
2.2 Military Standard:
held at various specified temperatures.
MIL-P-27401C Propellant Pressurizing Agent, Nitrogen
1.2 This test method describes the test apparatus and related
operating procedures for evaluating the total mass flux that is
3. Terminology
evolved from a material being subjected to temperatures that
3.1 Definitions:
are between 298 and 398K. Pressures external to the sample
−3 −5
3.1.1 AT cut crystal, n—a quartz crystal orientation that
effusion cell are less than 7 3 10 Pa (5 3 10 torr).
minimizes the temperature coefficient (frequency change ver-
Deposition rates are measured during material outgassing tests.
sus temperature) over a wide range of temperature.
A test procedure for collecting data and a test method for
3.1.2 collected volatile condensable material, CVCM,
processing and presenting the collected data are included.
n—(from Test Method E 595). The quantity of outgassed
1.3 This test method can be used to produce the data
matter from a test specimen that condenses on a collector
necessary to support mathematical models used for the predic-
maintained at a specific constant temperature for a specified
tion of molecular contaminant generation, migration, and
time and measured before and after the test outside the
deposition.
chamber.
1.4 All types of organic, polymeric, and inorganic materials
3.1.2.1 Discussion—CVCM is specific to Test Method
can be tested. These include polymer potting compounds,
E 595 and is calculated from the condensate mass determined
foams, elastomers, films, tapes, insulations, shrink tubing,
from the difference in mass of the collector plate before and
adhesives, coatings, fabrics, tie cords, and lubricants.
after the test in a controlled laboratory environment. CVCM is
1.5 There are two test methods in this standard. Test Method
expressed as a percentage of the initial specimen mass. The
A uses standardized specimen and collector temperatures. Test
view factor is not considered; so all the VCM outgassing from
Method B allows the flexibility of user-specified specimen and
the sample may not be collected. Care should be used in
collector temperatures, material and test geometry, and user-
comparing the CVCM from Test Method E 595 with VCM
specified QCMs.
from this test method.
1.6 The values stated in SI units are to be regarded as the
3.1.3 differential scanning calorimetry, DSC, n—a tech-
standard.
nique in which the difference in energy inputs into a substance
1.7 This standard does not purport to address all of the
and a reference material is measured as a function of tempera-
safety concerns, if any, associated with its use. It is the
ture while the substance and reference material are subjected to
responsibility of the user of this standard to establish appro-
a controlled-temperature program.
priate safety and health practices and determine the applica-
3.1.4 effusion cell, n—a container, placed in a vacuum, in
bility of regulatory limitations prior to use.
which a sample of material can be placed and heated to some
2. Referenced Documents specified temperature.
3.1.4.1 Discussion—The container has a cylindrical orifice
2.1 ASTM Standards:
at one end so that evolving gases exit the cell in a controlled
E 177 Practice for Use of the Terms Precision and Bias in
manner. The effusion cell dimensions and orifice size are
This test method is under the jurisdiction of ASTM Committee E-21 on Space
Simulation and Applications of Space Technology and is the direct responsibility of Annual Book of ASTM Standards, Vol 14.02.
Subcommittee E21.05 on Contamination. Annual Book of ASTM Standards, Vol 15.03.
Current edition approved Oct. 10, 2000. Published January 2001. Originally Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700
published as E 1559 – 93. Last previous edition E 1559 – 93. Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
E 1559
specified such that there is free molecular flow of the evolving 3.1.14 total outgassing rate, n—the net rate of mass loss
gasses and a predictable molecular flux from the orifice. from a material sample as a result of outgassing. Total
outgassing rate can be normalized per unit sample surface area
3.1.5 mass flux, n—the mass of molecular flux.
−2 −1
−2 −1
and expressed as g·cm ·s or it can be normalized per unit
3.1.6 molecular flux (molecules·cm ·s ), n—the number
−1 −1
initial sample mass and expressed as g·g ·s .
of gas molecules crossing a specified plane in unit time per unit
3.1.15 volatile condensable material, VCM, n—the matter
area.
that outgasses from a material and condenses on a collector
3.1.7 nonvolatile residue, NVR, n—the quantity of residual
surface that is at a specified temperature.
molecular and particulate matter remaining following the
3.1.15.1 Discussion—For this test method, this is the quan-
filtration of a solvent containing contaminants and evaporation
tity of outgassed matter from a test specimen that condenses on
of the solvent at a specified temperature.
surfaces maintained at QT2 or QT3. The VCM is calculated
3.1.8 outgassing, n—the evolution of gas from a material,
from the mass deposited on QCM2 or QCM3 and the view
usually in a vacuum. Outgassing also occurs in a higher
factor from the effusion cell orifice to the QCMs. VCM is a
pressure environment.
function of the outgassing test time and is expressed as a
3.1.9 quartz crystal microbalance, QCM, n—a device for
percentage of the initial specimen mass. In addition, VCM can
measuring small quantities of mass using the properties of a
be normalized with respect to the sample surface area and be
quartz crystal oscillator.
expressed as μg/cm . This is not the same as CVCM as
3.1.9.1 Discussion—The resonant frequency of a quartz
determined by Test Method E 595 (see 3.1.2).
crystal oscillator is inversely proportional to the thickness of
3.2 Acronyms:
the crystal. When the mass of a uniform deposit is small
3.2.1 GN , n—gaseous nitrogen.
relative to the mass of the crystal, the change in frequency is
3.2.2 LN , n—liquid nitrogen.
proportional to the mass of the deposit.
3.2.3 MAPTIS, n—Materials and Process Technical Infor-
3.1.10 QCM thermogravimetric analysis, QTGA, n—a tech-
mation Service.
nique in which a QCM is heated at a constant rate to remove
a collected deposit. 3.3 Definitions of Terms Specific to This Standard:
3.1.10.1 Discussion—This is performed to determine the 3.3.1 QCM1—the QCM that is operating at the temperature
evaporation characteristics of the species in the deposit. The TQ1 (cryogenic) for measuring the total outgassing rate.
mass of the deposit on the QCM is recorded as a function of 3.3.2 QCM2 and QCM3—the QCMs that are operating at
time or temperature.
temperatures TQ2 and TQ3 for the measurement of the
3.1.11 residual gas analyzer, RGA, n—a mass spectrometer deposition of outgassing matter.
mounted inside or attached to a vacuum chamber.
4. Summary of Test Method
3.1.11.1 Discussion—RGA can be used for identifying
gases in the vacuum chamber.
4.1 The test apparatus described in this test method is
−2 −1
3.1.12 total mass flux (g·cm ·s ), n—the summation of the
designed to measure outgassing rate data that can be used to
mass from all molecular species crossing a specified plane in
develop kinetic expressions for use in models that predict the
unit time per unit area.
evolution of molecular contaminants and the migration and
3.1.13 total mass loss, TML, n—total mass of material
deposition of these contaminants on spacecraft surfaces. Ma-
outgassed from a test specimen that is maintained at a specified
terials that contain volatile species that will be outgassed under
constant temperature and operating pressure for a specified
the temperature and vacuum conditions of this test method can
time and measured within the test chamber. TML is expressed
be characterized. The quartz crystal microbalances used in this
as a percentage of the initial specimen mass. In addition, TML
test method provide a sensitive technique for measuring very
can be normalized with respect to the sample surface area and
small quantities of deposited mass. In addition to providing
be expresed as μg/cm .
data for kinetic expressions, the reduced data can be used to
3.1.13.1 in-situ TML, n—calculated from the mass depos-
compare the outgassing behavior of different materials for
ited on a cryogenically cooled QCM and the view factor from material selection purposes.
the effusion cell orifice to the QCM.
4.2 There are two test methods in this standard. Test Method
3.1.13.2 Discussion—In-situ TML is a function of the
A is the standard procedure using prescribed configurations and
outgassing test time and is expressed as a percentage of the temperatures. Test Method B allows for the use of spacecraft
initial specimen mass. This is not necessarily the same as the
system specific temperatures, configurations, and QCM collec-
TML determined by Test Method E 595. tor surface finishes.
3.1.13.3 ex-situ TML, n—total mass of material outgassed 4.3 The measurements are made by placing the material
from a test specimen that is maintained at a specified constant
sample in an effusion cell so that the outgassing flux leaving
temperature and operating pressure for a specified time and the cell orifice will impinge on three QCMs which are arranged
measured outside the test chamber.
to view the orifice. A fourth QCM is optional. The effusion cell
3.1.13.4 Discussion—Ex-situ TML is calculated from the is held at a constant temperature in the high vacuum chamber
mass of the specimen as measured before and after the test in and has a small orifice directed at the QCMs. The QCMs are
a controlled laboratory environment and is expressed as a controlled to selected temperatures. The total outgassing rate is
percentage of the initial specimen mass. (From Test Method determined from the collection rate on a cryocooled QCM. At
E 595.) the end of the isothermal test, the QCMs are heated in a
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
E 1559
controlled manner to determine the evaporation characteristics a schematic of the systems, and Fig. 2 shows the vacuum
of the deposits. chamber and internal configuration.
4.4 The effusion cell is loaded from the vacuum interlock 5.2 Vacuum Chamber—The principal components of the
chamber to the main test chamber and is positioned at a fixed vacuum chamber are the main test chamber, the vacuum
distance and angle with respect to the QCM surfaces. The interlock chamber, and cryogenic shrouds (for example, LN ).
effusion cell is temperature controlled to provide constant and A high-vacuum gate valve is used to isolate the main test
uniform heating of the sample. The vacuum interlock chamber chamber from the interlock chamber. This allows the effusion
is a device that enables the expedient introduction of the test cell to be withdrawn or inserted into the main chamber without
sample into the high vacuum of the main test chamber. Use of the loss of high vacuum in the main chamber. High-vacuum
the interlock chamber to load and unload samples prevents loss electrical and mechanical feedthroughs are used to access the
of vacuum in the main chamber and diminishes the need to interior of the chamber.
pump it down before each test. 5.3 Internal Configuration—Three quartz crystal microbal-
4.5 The QCM collection method for measuring the total ances (QCMs) (a fourth QCM is optional), an effusion cell, and
outgassing rate from a sample is an indirect technique. Rather cryogenic heat sinks in the chamber are the principal compo-
than directly measuring sample mass loss, the basic measure- nents. The cryogenic heat sinks are used to ground the QCMs
ment is the fraction of the flux that condenses on the cryogeni- thermally and to cool shrouds which surround the effusion cell
cally cooled QCM collector at a point in the outgassing flow and QCMs. The cold shrouds limit molecular contaminant
field. That point in the flow field is defined as the geometric fluxes to the line-of-sight outgassing flux from the effusion cell
location of the QCM relative to the effusion cell orifice, which orifice to the collector QCMs. The cryogenic heat sink system
is at a fixed location. To determine the rate of sample mass loss (LN reservoirs) and shrouds, effusion cell, and QCMs are
from the rate of QCM collection, the view factor from the shown in Fig. 2.
QCM to the effusion cell orifice and the angular distribution of 5.3.1 The QCMs are thermally shielded from each other so
flux leaving the orifice must be determined. This relationship that the temperatures of each can be controlled independently.
can be calculated from the apparatus geometry and the effusion Each QCM has its own temperature sensing and control
cell orifice dimensions. system.
4.6 A QCM thermogravimetric analysis (QTGA) test is also 5.3.2 Each QCM contains two crystals (one for mass
included in the procedure. This technique heats the QCMs at a collection and one for reference), the oscillator electronics, and
constant rate to measure evaporation characteristics of the a temperature sensor. The QCM crystals shall have optically
deposits collected on the QCMs. The QTGA also provides an polished surfaces (60/40 cerium polish). Uncoated, aluminum
effective means to clean the QCM surfaces before subsequent electrodes shall be used for the sensin
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