MISSE 2 PEACE Polymers Atomic Oxygen Erosion Experiment on the International Space Station

Abstract

Forty-one different polymer samples, collectively called the Polymer Erosion and Contamination Experiment (PEACE) Polymers, were exposed to the low Earth orbit (LEO) environment on the exterior of the International Space Station (ISS) for nearly 4 years as part of Materials International Space Station Experiment 2 (MISSE 2). The objective of the PEACE Polymers experiment was to determine the atomic oxygen erosion yield of a wide variety of polymeric materials after long-term exposure to the space environment. The polymers range from those commonly used for spacecraft applications, such as Teflon ® FEP, to more recently developed polymers, such as high temperature polyimide PMR (polymerization of monomer reactants). Additional polymers were included to explore erosion yield dependence upon chemical composition. The MISSE PEACE Polymers experiment was flown in MISSE Passive Experiment Carrier 2 (PEC 2), tray 1, attached to the exterior of the ISS Quest Airlock. It was exposed to atomic oxygen along with solar and charged particle radiation. MISSE 2 was successfully retrieved during a space walk on July 30, 2005 during Discovery's STS-114 Return to Flight mission. Details on the specific polymers flown, flight sample fabrication, pre-flight and post-flight characterization techniques, and atomic oxygen fluence calculations are discussed along with a summary of the atomic oxygen erosion yield results. The MISSE 2 PEACE Polymers experiment is unique because it has the widest variety of polymers flown in LEO for a long duration and was exposed to an unusually clean LEO spacecraft environment. This experiment provides extremely valuable erosion yield data for spacecraft design purposes.

Surface Modification of Polystyrene with O Atoms Produced Downstream from an Ar/O2 Microwave Plasma

“…The release of CO 2 and cleavage of the polymer chain are often indicators of the formation of a weak boundary layer which was detected by washing the O atom treated PS samples, resulting in an oxygen concentration decrease of 5 ± 1 at % O compared to a 4.9 at % O decrease with VUV photo-oxidation [4]. Weight loss measurements due to the release of CO 2 during the reaction of O atoms with PS have been previously reported [20][21][22][23][24].…”

International utilization at the threshold of “assembly complete”—science returns from the International Space Station

“…MISSE results have been used to understand and calibrate how materials that are already in use on spacecraft degrade in the space environment (for example, polymers used for insulation, and solar array materials) and predict the durability of new materials (e.g., the solar cell materials that are planned for the Commercial Orbital Transportation System) [25]. The US Department of Defense (DOD) sponsored a MISSE-5 experiment that was designed to characterize the durability and electrical output of 39 advanced solar cell samples that could be used on future space exploration vehicles.…”

“…MISSE samples that are currently being tested on the ISS include materials that are part of the design of the new Orion vehicle [24]. In addition to several recent and upcoming publications, MISSE investigators have devised methods for measuring and predicting AO erosion yields, and have assembled data that will provide important reference for designers, developers, and builders of future spacecraft and instruments [24,25].…”

MISSE-X: An ISS external platform for space environmental studies in the Post-Shuttle era

“…[19] Over 200 publications have resulted from the MISSE research and development data; a few examples are referenced. [5][6][7][8][9][10][13][14][15][16][17] …”

“…[6][7][8][9][10] Yet, as space environmental durability researchers learn from each of the flown MISSE experiments, additional analyses and the assessment of newly developed materials and devices are still needed.…”