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Materials and Processes DivisionESA/ESTEC/TOS-QM
Mve/qmc 1
Materials and Processes SME Initiative
NUMEROUS PROBLEMSPARTICULARLY
INSULATION/GASKETING
DEGRADATION OFMATERIAL FUNCTION
OFFGASSING/AGEING/CORROSION
COMBUSTION
BIOLOGICALGROWTH
SMELL
LIFE SUPPORTINGATMOSPHERE
TOXIC GASES
LOSS OF MATERIALFUNCTION
TOXINES
AGRESSIONS TOLIFE
CATASTROPHICFAILURES
DISEASES
DISCOMFORT
Space Environment Effects : Manned Volumes
Materials and Processes DivisionESA/ESTEC/TOS-QM
Mve/qmc 2
Materials and Processes SME Initiative
Offgassing
Materials and Processes DivisionESA/ESTEC/TOS-QM
Mve/qmc 3
Materials and Processes SME Initiative
ECSS-Q-70-29 (former ESA PSS-01-729) : The determination of offgassing products from materials and assembled articles to be used in a manned space vehicle crew compartment
Purpose:Determine the identity and quantity of volatile offgassed products from materials and assembled articles.
Material screening test
• Quantity of Carbon Monoxide [g/g]• Quantity of total organics (pentane equivalent) [mg/g]• Identification of contaminants in excess of 10 mg/g of material
General test for materials/assembled articles
• Identification and quantification of all contaminants present• Use of T-values for acceptance
Offgassing test (1)
Materials and Processes DivisionESA/ESTEC/TOS-QM
Mve/qmc 4
Materials and Processes SME Initiative
Offgassing test (2)
• Acceptance Limits• Screening test
– Carbon Monoxide : <25 mg/g material– Total Organics : <100 mg/g material
• General test– No definitive acceptability defined by this test. Data are evaluated
by the Safety Office of the relevant project • for assessment of toxic hazard due to volatile
contamination evolved from the item under test• for assessment of the impacts on the potential
toxicity of the total quantity of offgassed products from all contaminant generating items for a given mission
Materials and Processes DivisionESA/ESTEC/TOS-QM
Mve/qmc 5
Materials and Processes SME Initiative
Offgassing test (3)
– Following primary acceptance criteria are relevant:
– The quantity of each individual offgassed product shall result in a predicted Spacecraft concentration below the SMAC value
– Toxic Hazard Index (T) shall not exceed 0.5. T is determined by calculating the ratio of the projected concentration of each offgassed product to its SMAC value and summing up these ratios for all offgassed products
T = C1/SMAC1 + C2/SMAC2 ..... + Cn/SMACn
Materials and Processes DivisionESA/ESTEC/TOS-QM
Mve/qmc 6
Materials and Processes SME Initiative
General test conditions
• Temperature 50 C
• Atmosphere : synthetic air or clean/dry air
• Pressure : 1 Atmosphere at 50 C
• Duration : 72 hrs
• Mass (material) 5g/liter test volume
Sampling : +/- 250 ml gas on trap after max. 12 hrs recovery to reach RT; flow rate sampling is +/- 25 ml/min.
Offgassing test Procedure (1)
Materials and Processes DivisionESA/ESTEC/TOS-QM
Mve/qmc 7
Materials and Processes SME Initiative
Test chambers
Different facilities are available e.g.:
Heraeus ovens 128 and 718 litersGlass bottles 1, 2.5 and 5 liters
Analyses:
Screening:TO/COGC with Methaniser and Flame Ionisation Detector
General testPre-concentrated samplingDesorption system : Model MW-1A from Rektorik (CH)GC with DB5MS from JW column (60m, diam 0.25mm, film 0.25 m) Mass spectrometer model Profile from Kratos (UK)
Offgassing test Procedure (2)
Materials and Processes DivisionESA/ESTEC/TOS-QM
Mve/qmc 8
Materials and Processes SME Initiative
Offgassing test Procedure (3)
Screening test
Materials and Processes DivisionESA/ESTEC/TOS-QM
Mve/qmc 9
Materials and Processes SME Initiative
Offgassing test Procedure (4)
Materials and Processes DivisionESA/ESTEC/TOS-QM
Mve/qmc 10
Materials and Processes SME Initiative
Odour Test
NASA-STD-6001 (former NHB 8060.1C)
Purpose
Determine if the odour is objectionable or revolting
• Odour of a material or assembled article is objectionable or revolting if an average of 2.5 or higher on an odour characteristic scale is obtained (0:undetectable, 1:Barely detectable, 2: Easely detectable, 3: objectionable,4: revolting).
• Sample preparation is the same as for Offgassing test
• Test panel shall consist of 5 qualified persons
Materials and Processes DivisionESA/ESTEC/TOS-QM
Mve/qmc 11
Materials and Processes SME Initiative
Flammability
Materials and Processes DivisionESA/ESTEC/TOS-QM
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Materials and Processes SME Initiative
• Identify flammable materials used, their amounts, thickness, exposed surface, exposure environment
• Identify propagation paths for exposed materials (including housing)
• If configuration is container, evaluate its capability to contain an internal fire
• If unacceptable configuration through the configuration assessment, there are two options:
Use fire break concepts to reduce flammability hazard by isolating the flammable materials
Conduct a test to show acceptability of configuration
Flammability configuration assessment (1)
Materials and Processes DivisionESA/ESTEC/TOS-QM
Mve/qmc 13
Materials and Processes SME Initiative
YES
ARE THERE ANY FLAMMABLE MATERIALS OR MULTIPLEAPPLICATIONS OF FLAMMABLE MATERIALS INAMOUNTS>0.1 LB OR 10 SQ. INCH IN MANNED COMPARTMENTS
OR>1.0 LB OR 12 LINEAR INCHES IN OTHERCOMPARTMENTS?
ACCEPTABLE
ARE EXTERIOR SURFACES AND ANYEXTERNALLY ATTACHED MATERIALSFLAMMABLE?
COULD A FIRE PROPAGATE ON THE SURFACE MORE THAN 6”IN MANNED COMPARTEMENTS OR 12” IN OTHERCOMPARTMENTS?
UNACCEPTABLE;MODIFICATIONREQUIRED (SEE GUIDELINES)
IS IT A CONTAINER?
WILL THE CONTAINER CONTAIN ANY INTERNAL FIRE?(SEE EXAMPLE CONTAINER CASES)
DOES THE CONTAINER CONTAIN AIR?
ARE INTERNAL IGNITION SOURCES PRECLUDED WHILETHE CONTAINER IS LOCATED IN THE ORBITER?
UNACCEPTABLE;MODIFICATIONREQUIRED(SEE GUIDLINES
ACCEPTABLE
ACCEPTABLEYES
ACCEPTABLENO
ACCEPTABLE
NO
NO
NO
YES
YES
YES
YES
YES
NO
NO
NO
Flammability configuration assessment (2)
Materials and Processes DivisionESA/ESTEC/TOS-QM
Mve/qmc 14
Materials and Processes SME Initiative
• Limitation of flammable materials by replacement with a non flammable one
• Restriction of propagation paths through
Covering of flammable materials with a nonflammable one
Separation of flammable materials (avoid propagation)
How to reduce flammability hazards
Materials and Processes DivisionESA/ESTEC/TOS-QM
Mve/qmc 15
Materials and Processes SME Initiative
Upwards Propagation Test (1)
ECSS-Q-70-21 (Former ESA PSS-01-721) : Flammability testing for the screening of space materials
Purpose :Determine if a material, when exposed to a standard ignition source, will self-extinguish and not transfer burning debris, which can ignite adjacent materials
Test criteria :Self extinguishing within 15 cmNo transfer of burning debris Burn Propagation time
Sample dimensions : 300 x 64 mm, worst case thicknessTest atmosphere : depends on application (24% O2 or more…)
Materials and Processes DivisionESA/ESTEC/TOS-QM
Mve/qmc 16
Materials and Processes SME Initiative
Upwards Propagation Test (2)
NiCr
Ignitor
TestSpecimen
64 mm
300
mm
Materials and Processes DivisionESA/ESTEC/TOS-QM
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Materials and Processes SME Initiative
Upwards Propagation Test (3)
Materials and Processes DivisionESA/ESTEC/TOS-QM
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Materials and Processes SME Initiative
Upwards Propagation Test (4)
Materials and Processes DivisionESA/ESTEC/TOS-QM
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Materials and Processes SME Initiative
Wire Flammability test (1)ECSS-Q-70-21 (Former ESA PSS-01-721) : Flammability testing for the screening of space materialsPurpose :Determine if a wire insulation system, when exposed to an external ignition source, will self-extinguish and not transfer burning debris, which can ignite adjacent materials
Acceptance criteriaPrior to flame application, while heating wire to maximal operation T, no spontaneous combustion, splitting insulation nor baring conductorDuring ignition and combustion no flaming droplets/particlesAfter burner is extinguished, cease flaming within 10 s and within a total burn length of 150 mm
Sample dimensions : 5 x 1m
Test atmosphere : depend on application (20% O2 or more…)
Materials and Processes DivisionESA/ESTEC/TOS-QM
Mve/qmc 20
Materials and Processes SME Initiative
Wire Flammability test (2)
Materials and Processes DivisionESA/ESTEC/TOS-QM
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Materials and Processes SME Initiative
Wire Flammability test (3)