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Accession Number N20120014249
Title Embrittlement of MISSE 5 Polymers After 13 Months of Space Exposure.
Publication Date Sep 2012
Media Count 16p
Personal Author A. Guo C. C. Ashmead G. G. Mitchell G. T. Yi K. K. DeGroh
Abstract Understanding space environment induced degradation of spacecraft materials is essential when designing durable and stable spacecraft components. As a result of space radiation, debris impacts, atomic oxygen interaction, and thermal cycling, the outer surfaces of space materials degrade when exposed to low Earth orbit (LEO). The objective of this study was to measure the embrittlement of 37 thin film polymers after LEO space exposure. The polymers were flown aboard the International Space Station and exposed to the LEO space environment as part of the Materials International Space Station Experiment 5 (MISSE 5). The samples were flown in a nadir-facing position for 13 months and were exposed to thermal cycling along with low doses of atomic oxygen, direct solar radiation and omnidirectional charged particle radiation. The samples were analyzed for space-induced embrittlement using a bend-test procedure in which the strain necessary to induce surface cracking was determined. Bend-testing was conducted using successively smaller mandrels to apply a surface strain to samples placed on a semi-suspended pliable platform. A pristine sample was also tested for each flight sample. Eighteen of the 37 flight samples experienced some degree of surface cracking during bend-testing, while none of the pristine samples experienced any degree of cracking. The results indicate that 49 percent of the MISSE 5 thin film polymers became embrittled in the space environment even though they were exposed to low doses (approx.2.75 krad (Si) dose through 127 mm Kapton) of ionizing radiation.
Keywords Aerospace environments
Charged particles
Earth orbital environments
International space station
Low earth orbits
Spacecraft construction materials
Thermal cycling tests

Source Agency National Aeronautics and Space Administration
NTIS Subject Category 84G - Unmanned Spacecraft
84C - Manned Spacecraft
84D - Spacecraft Trajectories & Flight Mechanics
Corporate Author National Aeronautics and Space Administration, Cleveland, OH. NASA John H. Glenn Research Center at Lewis Field.
Document Type Technical report
Title Note N/A
NTIS Issue Number 1307
Contract Number N/A

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