Ground-Laboratory to In-Space Atomic Oxygen Correlationfor the PEACE Polymers

摘要

The Materials International Space Station Experiment 2 (MISSE 2) Polymer Erosion andContamination Experiment (PEACE) polymers were exposed to the environment of low Earthorbit (LEO) for 3.95 years from 2001 to 2005. There were forty-one different PEACE polymers,which were flown on the exterior of the International Space Station (ISS) in order to determinetheir atomic oxygen erosion yields. In LEO, atomic oxygen is an environmental durabilitythreat, particularly for long duration mission exposures. Although space flight experiments, suchas the MIS SE 2 PEACE experiment, are ideal for determining LEO environmental durability ofspacecraft materials, ground-laboratory testing is often relied upon for durability evaluation andprediction. Unfortunately, significant differences exist between LEO atomic oxygen exposureand atomic oxygen exposure in ground-laboratory facilities. These differences include variationsin species, energies, thermal exposures and radiation exposures, all of which may result indifferent reactions and erosion rates. In an effort to improve the accuracy of ground-baseddurability testing, ground-laboratory to in-space atomic oxygen correlation experiments havebeen conducted. In these tests, the atomic oxygen erosion yields of the PEACE polymers weredetermined relative to Kapton H using a radio-frequency (RF) plasma asher (operated on air).The asher erosion yields were compared to the MISSE 2 PEACE erosion yields to determine thecorrelation between erosion rates in the two environments. This paper provides a summary ofthe MISSE 2 PEACE experiment; it reviews the specific polymers tested as well as thetechniques used to determine erosion yield in the asher, and it provides a correlation between thespace and ground-laboratory erosion yield values. Using the PEACE polymers' asher to in-spaceerosion yield ratios will allow more accurate in-space materials performance predictions to bemade based on plasma asher durability evaluation.