NASA has identified 30kW-class SEP systems as a high-value intermediate step toward higher power systems due to broad cross-cutting capability. Current NASA investments include advanced next-generation solar arrays and higher power electric propulsion technologies to enable 30kW-class SEP. The ESPA ring is one approach being considered for partner-based mission concepts and those capable of being launched as secondary payloads. In addition NASA is investing in EP development of 15kW class HET system using either direct-drive and/or high voltage power processing unit. The possibility for using Hall thrusters for lunar and Mars missions has also been well investigated. Hall thrusters have been found to be a good choice for Mars cargo missions and other studies have found Hall thrusters to be viable options for supporting lunar and Mars exploration. Another NASA study indicates that a cluster of eight 100 kW Hall thrusters would be well sized for manned Mars missions.
A nominal 15kW thruster with the capability to throttle down to 5kW should find broad applications on DoD and commercial ComSats. Hall thrusters could enhance many high power DoD and commercial missions such as satellite servicing, orbit maintenance, orbit raising and lowering, inclination changes, and repositioning. The system could also find near term application on an all-electric upper stage derived from Busek's ESPA orbit maneuvering system (OMS), a free flying spacecraft based on the ESPA ring that is being developed in cooperation with United Launch Alliance (ULA). A low power system presently utilizes four BHT-1500 Xe Hall effect thrusters and capable of delivering up to five ESPA class spacecraft to multiple orbits. The high power (30kW) version would be used for transportation of propellant to a LaGrange positioned fuel depot.
More »