ABSTRACT
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The space environment presents a variety of hazards for spacecraft. Not only are
there extremes of temperature and pressure to contend with, but the spacecraft must
also withstand a constant onslaught of energetic ionized particles and photons that
can damage both the spacecraft and its payload. Atomic oxygen (AO) poses a
serious hazard because it corrodes materials with which it comes into contact,
causing surface erosion and contamination of the spacecraft. High-energy photons
(UV, x-ray and gamma rays) that degrade the electrical, optical, thermal, and mech-
anical properties of materials and coatings are present. Charged particles also pose a
danger to the spacecraft. For instance, plasmas are a significant hazard because they
alter the spacecraft’s electrical ‘‘ground’’ potential through the buildup of charge.
After sufficient exposure, dielectrics may suddenly discharge, damaging sensitive
electronic components in the process. Individual energetic ionized particles such as
electrons, protons, alpha particles, and heavier ions are another hazard. They are able
to penetrate the spacecraft’s superstructure as well as the electronic, opto-electronic,
and microelectromechanical systems (MEMS) devices contained on board. As they
travel through matter, the particles collide with the atoms of the MEMS devices
materials, which in turn, liberate charge and disrupt the lattice structure. Both of these
effects contribute to the performance degradation of devices.
