Investigation of Propulsion System Requirements for Spartan Lite

This paper discusses the (chemical or electric) propulsion system requirements necessary to increase the Spartan Lite science mission lifetime to over a year. Spartan Lite is an extremely low-cost (\u3c $10M) spacecraft bus being developed at the NASA Goddard Space Flight Center to accommodate sounding rocket class (40 W, 45 kg, 35cm dia by 1 m length) payloads. While Spartan Lite is compatible with expendable launch vehicles, most missions are expected to be tertiary payloads deployed by the Space Shuttle. To achieve a one year or longer mission life from typical Shuttle orbits, some form of propulsion system is required. Chemical propulsion systems (characterized by high thrust impulsive maneuvers) and electrical propulsion systems (characterized by low-thrust long duration maneuvers and the additional requirement for electrical power) are discussed. The performance of the Spartan Lite attitude control system in the presence of large disturbance torques is evaluated using the Treetops dynamic simulator. This paper discusses the performance goals and resource constraints for candidate Spartan Lite propulsion systems and uses them to specify quantitative requirements against which the systems are evaluated