VASIMR’s radio frequency generator gets around that problem by never coming into contact with the ions. In that setup, ions colliding with the grid tend to erode it, limiting the power and lifetime of the rocket.
Nuclear time journey mars series#
Thanks to the radio frequency generator, VASIMR can reach power levels a hundred times as high as other engines, which simply accelerate their plasma by sending it through a series of metal grids with different voltages. Strong magnetic fields then channel the plasma out the back of the engine, propelling the rocket in the opposite direction. The radio frequency generator is then tuned to that same frequency, injecting extra energy into the ions. It does this by taking advantage of the fact that in a strong magnetic field – like those produced by superconducting magnets in the engine, ions spin at a fixed frequency. To optimise efficiency, the rocket’s second stage then heats the ions to about a million degrees, a temperature comparable to that at the centre of the sun. The plasma could produce thrust on its own if it were shot out of the rocket, but not very efficiently. This stage was tested for the first time on 2 July at Ad Astra’s headquarters in Webster, Texas. The radio frequency generator heats a gas of argon atoms until electrons “boil” off, creating plasma. VASIMR works something like a steam engine, with the first stage performing a duty analogous to boiling water to create steam. The engine is being developed by the Ad Astra Rocket Company, which was founded in 2005 by plasma physicist and former space shuttle astronaut Franklin Chang-Diaz. They provide much less thrust at a given moment than do chemical rockets, which means they can’t break free of the Earth’s gravity on their own. Ion engines, on the other hand, accelerate electrically charged atoms, or ions, through an electric field, thereby pushing the spacecraft in the opposite direction. Most of that fuel is used up in the initial push off the Earth’s surface, so the rockets tend to coast most of the time they’re in space. Traditional rockets burn chemical fuel to produce thrust. But now, researchers are testing a powerful new ion engine that could one day shorten the journey to just 39 days. There’s a growing chorus of calls to send astronauts to Mars rather than the moon, but critics point out that such trips would be long and gruelling, taking about six months to reach the Red Planet. The VASIMR ion engine could – if powered by an onboard nuclear reactor – take astronauts to Mars in just 39 days (Illustration: Ad Astra Rocket Company)
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