Power requirements for an electric propulsion Earth orbital transport vehicle (EOTV), which can effectively deliver large payloads using much less propellant than chemical transfer methods, are addressed. The power beaming concept is described. Arcjets, magnetoplasmadynamic (MPD) thrusters, and ion engines are covered. Power supply characteristics are discussed for nuclear, solar and power-beaming systems. Operational characteristics are given for each, as are the effects of the power supply alternative on the overall craft performance. Because of its modular nature, the power beaming can meet the power requirements of all three electric propulsion types. Commonality of approach allows different electric propulsion approaches to be powered by means of a single power supply approach. Power beaming exhibits better flexibility and performance than onboard nuclear or solar power systems. >

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Performance enhancement using power beaming for electric propulsion Earth orbital transporters

This paper outlines the power requirements of electric propulsion technology being developed today, including arcjets, magnetoplasmadynamic (MPD) thrusters, and ion engines. Power supply characteristics are discussed for nuclear, solar, and power‐beaming systems. Operational characteristics are given for each, as well as the impacts of the power supply alternative on the overall craft performance. The power‐beaming approach, because of its modular nature, is able to meet the power requirements of all three electric propulsion types. Also, commonality of approach allows different electric propulsion approaches to be powered by a single power supply approach. Power beaming exhibits better flexibility and performance than on‐board nuclear or solar power systems.

Power considerations for electric propulsion earth orbital transporters utilizing power beaming

The objectives of an efficient electric propulsion (EP) system capable of meeting the requirements of the SDI Organization missions are discussed, with consideration given to each of the three EP applications, namely, the orbit raising, the on-orbit station-keeping, and the defensive maneuvering. Space experiments involving EP are being planned around the arcjet and ion thruster types, with the short-term research being focused on the NH3 arcjet for the SP-100 flight missions. Demonstrated 30 kW arcjet sustained life of the arcjet (as compared with less than 3 kW for the ion engine) and the arcjet's inherent simplicity offer low risk and minimum cost for the SP-100 flight demonstration objectives. Long-term research on high thrust-density ion propulsion is aimed at 5 to 25 kW operation in the 5000-sec specific impulse range. 30 refs.

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA345760&Location=U2&doc=GetTRDoc.pdf

Leonard Caveny

Papers

SDIO electric propulsion objectives and programs