“In which are described methods for using tethers to generate electricity, as propulsion and for ISS reboost. What I'm wondering is if you could use one tether to generate power, and several other tethers to power it. The only trouble I see is if the drag is to great over thrust. Not perpetual motion, just feeding/pushing a bunch off the magnetic field. <br /><br />What your saying is this can't work, even with a photovoltaic assist?”<br /><br />No, what they are saying that you would REQUIRE additional power to raise orbit. The photovoltaic part would not be assisting it. It would be the only thing powering it. <br /><br />Here is how it works, a spacecraft traveling along lets out a tether and drags the tether through the earth’s magnetic field generating electrical power.<br /><br /><br />Generators on earth do the same thing. They move a magnet through a coil of wires and generate power. <br /><br />In both cases the generator or the tether take one form of energy and turns it into another. <br /><br /><br />In the case of the generator the generator takes the kinetic energy of the moving magnet and turns it into electrical power. If whatever is causing the magnet to move stops, then the magnet will slow to a stop even without friction. <br /><br /><br />An example of this is the regenerative braking on hybrid cars. The brakes takes the energy present in the turning wheels and turns it into electricity. Slowing the car and generating power. <br /><br />In the case of the tether, the tether takes the kinetic energy of the spacecraft and turns it into electrical power. As a consequence the spacecraft will slow down and the orbit will lower.<br /><br /><br />Adding tethers will only cause the spacecraft to slow down faster. You will generate more electical power in less time but you can not generate more electrical energy than what was present in the kinetic energy of the craft to start with. <br /><br />If you want to use a tether to raise orbit you will need to add some outside power