and devices, leading to trapped charge buildup within the dielectric material. Design guidelines for assessing and controlling spacecraft charging effects, published by NASA, provide guidance for incorporating design practices to mitigate these effects. Where possible, the use of filters to prevent the propagation of discharge-event-created signal transients may be used. The use of surface coatings (paint, etc.) and materials which provide dissipation of deposited charge, is recommended. Shielding of electronic assemblies to reduce the flux of high- energy electrons impinging on sensitive devices and materials are some of the provisions typically utilized in addressing charging effects. Other Space Environment Considerations [Purvis93] [Tribble95] Vacuum Environment Design for operation in the vacuum environment of space results in constraints in the selection of materials which may be used, and in the design of thermal control provisions. During exposure to very low pressure conditions, many materials exhibit a mass loss through outgassing. Most materials contain fractional amounts of volatile chemicals, either on the surface of the material or dispersed through it. The degree of outgassing has been shown to decline exponentially as a function of time, inversely as a power of time, or at a constant rate over time, depending on whether the process involved is desorption, diffusion, or decomposition (or some combination of these processes). Desorption is the release of surface molecules which were held in place by physical or chemical forces. Diffusion is the process by which molecules propagate to the material surface, driven by random thermal motion, some of these have sufficient energy to escape surface forces and propagate into the local environment. Decomposition is the process in which material breaks down into other compounds which then outgas through desorption or diffusion. Once the molecules leave the surface of the material, they follow ballistic trajectories and usually interact with any surface having