Design of a power management and distribution system for a thermionic-diode powered spacecraft
- National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center
The Electrical Systems Development Branch of the Power Technology Division at the NASA Lewis Research Center in Cleveland, Ohio is designing a Power Management and Distribution (PMAD) System for the Air Force`s integrated Solar Upper Stage (ISUS) Engine Ground Test Demonstration (EGD). The ISUS program uses solar-thermal propulsion to perform orbit transfers from Low Earth Orbit (LEO) to Geosynchronous Orbit (GEO) and from LEO to Molnya. The ISUS uses the same energy conversion receiver to perform the LEO to High Earth Orbit (HEO) transfer and to generate on-orbit electric power for the payloads. On-orbit power generation is accomplished via two solar concentrators heating a dual-cavity graphite-core which has Thermionic Diodes (TIDs) encircling each cavity. The graphite core and concentrators together are called the Receiver and Concentrator (RAC). The TID-emitters reach peak temperatures of approximately 2,200 K, and the TID-collectors are run at approximately 1,000 K. Because of the high Specific Impulse (I{sub sp}) of solar thermal propulsion relative to chemical propulsion, and because a common bus is used for communications, GN and C, power, etc., a substantial increase in payload mass is possible. This potentially allows for a step-down in the required launch vehicle size or class for similar payload mass using conventional chemical propulsion and a separate spacecraft bus. The ISUS power system is to provide 1,000 W{sub e} at 28 {+-} 6V{sub dc} to the payload/spacecraft from a maximum TID generation capability of 1,070 W{sub e} at 2,200 K, producing power with this quality, protecting the spacecraft from electrical faults and accommodating operational constraints of the TIDs is the responsibility of the PMAD system. The design strategy and system options examined along with the proposed designs for the Flight and EGD configurations are discussed.
- OSTI ID:
- 474472
- Report Number(s):
- CONF-960805-; TRN: IM9723%%365
- Resource Relation:
- Conference: 31. intersociety energy conversion engineering conference, Washington, DC (United States), 9-14 Aug 1996; Other Information: PBD: 1996; Related Information: Is Part Of Proceedings of the 31. intersociety energy conversion engineering conference. Volume 1: Aerospace power systems, aerospace technologies; Chetty, P.R.K.; Jackson, W.D.; Dicks, E.B. [eds.]; PB: 681 p.
- Country of Publication:
- United States
- Language:
- English
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