The solar electric propulsion stage concept for high energy missions.

Definition of multimission and engine performance requirements for candidate solar electric propulsion stage configurations, considering launch vehicle compatibility, electric propulsion integration, payload requirements, and the effects of environmental extremes. Electric propulsion power options include two solar array power levels (15/22 kW), up to twelve electric thrustors of 30 cm diameter and 2.7 kW each, five to eight power conditioning units, and a maximum mercury propellant capacity of 1530 kg. In performance, the stage with a dry weight of 700 to 900 kg can deliver a net mass of 756 kg into Saturn orbit, 329 kg into a tight Mercury orbit, and 334 kg within 0.1 AU of the sun. The stage can also deliver a round trip payload of 3350 kg to geosynchronous orbit and return from an intermediate elliptical orbit using the Shuttle/Tug. Thus, a versatile stage is developed which competes effectively in performance with existing integrated spacecraft and promises considerable savings in total program costs.