Spacecraft design lifetime

A general discussion of issues that drive and limit spacecraft design lifetime is presented. The effects of varying the spacecraft lifetime requirement on different subsystems are explored, and typical spacecraft mass and cost profiles are deduced. Quantitative analyses confirm that the design lifetime is a key requirement in sizing various subsystems and significantly affects the spacecraft mass and cost to initial operating capability. The analysis introduces a formally defined economic metric, the cost per operational day, to help guide the specification of the design lifetime requirement. Preliminary results suggest that other factors should also be taken into account in specifying the design lifetime, namely, the loss of value resulting from technology obsolescence as well as the volatility, of the market the system is serving in the case of a commercial satellite.