Electrodynamic tethers. 1. Power generator in LEO. 2. Thrust for propulsion and power storage

Technical Report · Sun Apr 01 00:00:00 EST 1984

OSTI ID:5621994

Mccoy, J E

An electrodynamic tether consists of a long insulated wire in space whose orbital motion cuts across lines of magnetic flux to produce an induce voltage that in typical low orbits averages about 200 v/km. Such a system should be capable of generating substantial electrical power, at the expense of IXB drag acting on its orbital energy. If a reverse current is driven against the induced voltage, the system should act as a motor producing IXB thrust. A reference system was designed, capable of generating 20 KW of power into an electrical load located anywhere along the wire at the expense of 2.6N (20,000 J/sec) drag on the wire. In an ideal system, the conversion between mechanical and electrical energy would reach 100% efficiency. In the actual system part of the 20 KW is lost to internal resistance of the wire, plasma and ionosphere, while the drag force is increased by residual air drag. The 20 KW PMG system as designed is estimated to provide 18.7 KW net power to the load at total drag loss of 20.4 KJ/sec, or an overall efficiency of 92%. Similar systems using heavier wire appear capable of producing power levels in excess of 1 Megawatt at voltages of 2-4 KV, with conversion efficiency between mechanical and electrical power better than 95%. The hollow cathode based system should be readily reversible from generator to motor operation by driving a reverse current using onboard power.

• Research Organization: National Aeronautics and Space Administration, Houston, TX (USA). Lyndon B. Johnson Space Center
• OSTI ID: 5621994
• Report Number(s): N-85-13901
• Resource Relation: Other Information: In NASA, Lewis Research Center, space power, 275-284 p., (N--85-13880 05-20)
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
SPACECRAFT POWER SUPPLIES
COUPLING
ELECTRODYNAMICS
INDUCTION GENERATORS
IONOSPHERE
EARTH ATMOSPHERE
ELECTRIC GENERATORS
ELECTRONIC EQUIPMENT
EQUIPMENT
PLANETARY IONOSPHERES
POWER SUPPLIES
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