Beam-powered propulsion, also known as directed energy propulsion, is a class of aircraft or spacecraft propulsion that uses energy beamed to the spacecraft from a remote power plant to provide energy. The beam is typically either a microwave or a laser beam, and it is either pulsed or continuous. A continuous beam lends itself to thermal rockets, photonic thrusters, and light sails. In contrast, a pulsed beam lends itself to ablative thrusters and pulse detonation engines.[1]
The rule of thumb that is usually quoted is that it takes a megawatt of power beamed to a vehicle per kg of payload while it is being accelerated to permit it to reach low Earth orbit.[2]
Other than launching to orbit, applications for moving around the world quickly have also been proposed.
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