In one mechanism, the elongation in a single plane is used to make a series of stretches and position holds, similar to the way a caterpillar moves. An electrically powered spacecraft propulsion system uses electric motor technology to propel spacecraft in outer space. Most systems are based on electrically accelerating propellant to high speed, while some systems are based on electrodynamic tethers principles of propulsion to the magnetosphere. See also Electric generator Electric vehicle motor Goodness factor Motor capacitor Motor controller Regenerative brake Traction motor Notes References Bibliography Houston, Edwin J.; Kennelly, Arthur, Recent Types of Dynamo-Electric Machinery, American Technical Book Company 1897, published by P.F. Collier and Sons New York, 1902 Further reading External links SparkMuseum: Early Electric Motors The Invention of the Electric Motor 1800 to 1893, hosted by Karlsrushe Institute of Technology's Martin Doppelbauer MAS.865 2018 How to Make Something that Makes (almost) Anything, slow motion gifs and oscillograms for many kinds of motors. Electromagnetic components Energy conversion British inventions Magnetic propulsion devices Hungarian inventions