Accession Number : ADA180276


Title :   Thermal and Dynamical Effects on Electrodynamic Space Tethers


Descriptive Note : Final rept.


Corporate Author : ARMY MILITARY PERSONNEL CENTER ALEXANDRIA VA


Personal Author(s) : Prall, Jr, John S


Full Text : http://www.dtic.mil/get-tr-doc/pdf?AD=ADA180276


Report Date : 08 May 1987


Pagination or Media Count : 138


Abstract : Electrodynamic tethers are essentially long conducting wires which, when deployed from an orbiting satellite, can generate power by converting orbital mechanical energy into electrical energy for use on the satellite. They can accomplish this as a consequence of the electrodynamically induced voltage caused by the movement of the tether with respect to the earth's magnetic field; this acts to drive a current through the tether to an on-board load. Conversely, if current is forced through the tether from the satellite, the elecytrodynamic interaction will induce a force and allow the tether to perform as a so-called Alfven engine. An analytical and numerical analysis was carried out on the operation of an electrodynamic tether system used for power generation and/or thrusting in a space environment. Three problems were examined. First, the efficiency of an uninsulated tether of prescribed design, as determined by the magnitude of current leakage along its length due to positive ion capture and secondary electron emissions, was compared to that of a perfectly insulated tether of identical design. Second, the effects on system efficiency of variations in the design parameters of the tether and the orbit in which it operates wee examined by means of a numerical analysis of the thermal balance of the system. Third, the effects which the mode of operation of the tether has on the classical elements of the orbit in which it operates were examined through a numerical analysis.


Descriptors :   *ARTIFICIAL SATELLITES , *EARTH ORBITS , *ELECTRIC POWER PRODUCTION , *ELECTROMAGNETIC INDUCTION , *GEOMAGNETISM , *TETHERING , CATIONS , ELECTRODYNAMICS , HEAT BALANCE , MAGNETIC FIELDS , MECHANICAL ENERGY , NUMERICAL ANALYSIS , ONBOARD , OPERATION , SECONDARY EMISSION , SPACE ENVIRONMENTS , THERMAL PROPERTIES , THESES , VOLTAGE


Subject Categories : Non-electrical Energy Conversion
      Electric Power Production and Distribution
      Astronautics


Distribution Statement : APPROVED FOR PUBLIC RELEASE