Space environment effects and satellite design

The space environment continues to be a major cause of anomalies in communications satellites, in spite of much knowledge gained over the past three decades. The two most common causes of anomalies are surface charging and deep dielectric (dis)charging, but other effects, such as total radiation dose, must be accounted for in the design, particularly of solar arrays and electronics. Many space environments are difficult to predict accurately, for example the peak intensity of the developing Solar Cycle 23, and in particular the radiation dose to be expected from it. The recent Leonid storm provides an example of the extreme variation possible between prediction and reality. Telesat's investigations into space-weather-related anomalies are described, and our approach to minimizing susceptibility of satellites to space weather is outlined. Space environment specifications for procurement contracts are reviewed and some general design guidelines are described.