Light gas gun - a hypervelocity launcher that exploits the high speed of sound in light gases to accelerate projectiles velocities to very high speeds, in some cases up to Earth escape velocity.
Light gas guns have been proposed for space launch. Light gas guns are touted for their relative simplicity: they involve no combustion or detonation. They rely instead on the very high sound speed of a hot, light gas (hydrogen or helium). The gas is typically very rapidly heated by a variety of means, intense compression being a common approach in laboratory gas guns. Light gas guns have also been faulted for poor scalability, since (in some designs at any rate), space launch would require several stages, with the first stage being massive.
Among the most promising of a number of proposals is one from Quicklaunch Inc. They propose reviving the gas gun developed in Lawrence Livermore Lab's SHARP effort as a testbed and proof-of-concept. The company's eventual goal is an ocean-going launcher that could reach a variety of orbits, for ISS resupply and LEO propellant depots for interplanetary missions.
Further reading
- Light gas gun on Wikipedia
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