Integrated launch vehicle and spacecraft avionics - A search for a feasible option

Schemes for enabling payload spacecraft avionics to serve as part of the upper-stage boost vehicle's avionics are discussed. The measure would be a means of lowering inertial upper stage costs. The spacecraft would furnish guidance, navigation, and control functions, while leaving radio guidance to ground control. Final propulsive kicks are currently supplied either by an integral propulsive unit, such as for the DMSP and Tiros-N spacecraft, or by bolted-on boosters like the IUS or Centaur. Present standard payload equipment that would serve for booster avionics systems include three-axis gyroscopes, reaction control systems, computers, and star trackers. Favorable costs are projected for integrated booster-payloads, provided more than one unit is built and the development costs can be kept low enough.