ABSTRACT
The radiation and other aspects of the space environment that have damaging effects on various power system components are discussed in this chapter. The charged particles impinging on the spacecraft surface slow down by collision and lose their energy. The deposited energy in the material causes damage by atomic excitation in metals and semiconductors, and ionization in plastic materials. Various particles lose energy at different rates as they penetrate the surface and cause damage at different rates. The higher the rate, the more damage they produce. The damage is most severe in the Van Allen belts because of the high level of radiation. Although the belt region, which is between the low Earth orbit and the crowded geosynchronous orbit, is potentially a valuable piece of orbital real estate, the region has remained relatively unexplored because of the practical and economic difficulties of shielding conventional satellites from charged particles. NASA has measured charged particles in many orbits to develop and validate a computer model. In 2002, nine astronauts aboard the ISS each wore a 0.04-inch square silicon chip dosimeter that measured the levels of radiation they were exposed to during space walks. On Earth, similar devices are used in hospitals worldwide to measure the radiation given to cancer patients.
