The Spacecraft Structure and Thermal Design Considerations

The general size and shape constraints for the Telstar satellite have been reviewed in a previous paper. 1 The present paper discusses the important features of the spacecraft structural and thermal design. The function of the spacecraft structure is to support and isolate the electronic components from the shock and vibration loads due to launch, and to provide a geometry compatible with an isotropic solar cell power plant. 2 Since a majority of the critical components used in the electronics package were designed to operate in a room temperature environment, a major objective of the thermal design was to provide a package temperature as close to room temperature as possible. This objective was to be maintained during a two-year life in orbit. Therefore, all orbital effects on the satellite temperature had to be considered: full sunlight, maximum eclipse orbit, seasonal variation of the solar constant, satellite orientation, and long-term effects on surface coatings exposed to ultraviolet light and other radiation effects. Another thermal objective 973