Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site ssc-vax.UUCP Path: utzoo!watmath!clyde!burl!mgnetp!ihnp4!houxm!houxz!vax135!cornell!uw-beaver!ssc-vax!eder From: eder@ssc-vax.UUCP (Dani Eder) Newsgroups: net.space Subject: Re: Tethered Generators Message-ID: <40@ssc-vax.UUCP> Date: Wed, 8-Aug-84 11:58:43 EDT Article-I.D.: ssc-vax.40 Posted: Wed Aug 8 11:58:43 1984 Date-Received: Fri, 10-Aug-84 02:00:58 EDT References: <671@ihuxt.UUCP> Organization: Boeing Aerospace, Seattle Lines: 26 [7 August 1984] The way you make up frictional drag losses in LEO with a conductive tether is to use a solar array to force current up the tether. By reversing the 'generator effect', you now have a motor. The system now gains orbital energy at the expense of electricity. Force on a current-carrying wire in a magnetic field is IL x B where I=current in Amperes, L=length of wire(meters),x= cross product (math function that tells which way force is directed), and B is magnetic field in Teslas. In order to have a one way current, you have to collect electrons at one end (a large sheet of aluminum), and get rid of them at the other (an electron gun). Losses in the system are parasitic power to run the electron gun (10-20%), and I*I*R resistance losses in the wire. Although this propulsion system only works well in the ionosphere, it gets lots better thrust per watt than ion propulsion, and consumes no fuel to boot. It can also be scaled arbitrarily small, i.e. 1 Ampere, 100 meter wire, television type electron gun, = 1/300 newton. Dani Eder / Boeing Aerospace Company / ssc-vax!eder