Reliability and Availability of Redundant Satellite Orbit Systems

In order to find the optimum redundant satellite orbit system, the formulas are derived for reliability and availability of redundant systems composed of two parallel, three parallel, one functioning and one standby, and two parallel and one standby satellites, where both the probability of a start or switchover and the necessary delay time for a start or switchover are taken into consideration. The calculation by these formulas shows the relation among the reliability, availability, launch probability, and launch delay time, as illustrated by numerical examples of conventional rockets and space shuttles.