A study of increased reliability and lifetimes for future communications satellites, volume 1

An analysis of the orbital life performance of 150 communications satellites was undertaken and supplemented by a literature search, an independent investigation of life limiting spacecraft elements, and visits to North American and European organizations, with the aim of improving cost effectiveness and service availability of communications satellites by extending design lifetimes to 10-15 years. It is shown that 20% of satellites failed to achieve full operational status in orbit. Satellites display a nonconstant failure rate consistent with extensive redundancy. Production expertise has matched the steady increase in design lifetimes which are, on an average, attained. A nine to ten year life is the present state of the art. Major satellites life limiters are: NiCd batteries (problems unsolved); TWTAs, radiation degradation, microwave transistors, inadequate parts screening, fuel depletion (requiring individual trade off decisions); design faults, command disabling, poor redundancy, repeater electronics, power distribution, motors/bearings, bladders, thrusters, thermal cycle stresses, static discharging, microprocessor applications (requiring design/production control and further research).