Miniaturized Satellite Development for Responsive Space Missions

ABSTRACT:The Hall thruster propulsion system consists of the thruster, cathode, propellant management system and the power processing electronics. The power processing unit (PPU) represents largest fraction of the system dry mass. In addition, the delivery time and cost of radiation hard electronics and issues regarding long-term pre-launch fuel storage make it difficult for electric propulsion systems to meet the operational needs of responsive space missions. In response to the Air Force need for satellites that are both operationally responsive to a launch command and operationally responsive to the warfighter on-orbit, Busek is purposing a paradigm shift from the traditional architecture of electric propulsion systems. The proposed system leverages our flight qualified low power Hall thruster technology. We propose to power the propulsion system using a single multifunctional power converter that has the potential to significantly reduce the PPU cost, mass, volume. We will also investigate the technical feasibility of a non-toxic iodine fueled thruster as a means of reducing the stored propellant tankage mass and volume. Iodine would be stored as a solid allowing pre-fueled long term storage of the propulsion system until a responsive space need arises. In Phase I we will conduct a comprehensive system design and mass optimization study supported by an experimental demonstration using a single multifunctional power converter to power the cathode and thruster. In Phase II we will design and build engineering prototypes of each subsystem and conduct a TRL 6 integrated system demonstration. At the conclusion of the program the integrated system will be delivered to AFRL for extended duration testing in facilities.BENEFIT:The AFRL IHPRPT Program is investing in the development of long life low power HET systems. A key technology identified in the Beyond IHPRPT study is an extremely long life, low mass variant of the BHT-200 and BHT-600 HET systems. The multi-functional converter concept is attractive for its reduction in overall propulsion system mass complexity and cost. Hall thrusters have also been identified as a key technology for NASAs vision of space exploration. NASA missions beyond Earth orbit can be enabled by the wide throttle range and broad Isp-thrust operation of Hall thrusters. A study conducted by the SMD ISPT Project in 2004 confirmed the significant potential of EP for space science missions, including orbiters about Pluto, Neptune, and Uranus; rendezvous/return with Kuiper Belt Objects and primitive bodies in the outer Solar System; and extensive surveys of major asteroid groups. Commercial satellite manufacturers; SS/L, Boeing, Lockheed Martin and Orbital Sciences have all shown a strong interest in low power HET systems for primary propulsion on LEO spacecraft and station keeping on GEOSats.