http://www.flightglobal.com/articles/2008/08/05/226329/nasa-to-test-plasma-engine-on-space-station.html

05/08/08 Flight International

By Rob Coppinger

NASA expects to sign an agreement to test a new propulsion system on the International Space Station, according to the US space agency's administrator Michael Griffin.

At the AirVenture show in Oshkosh on 29 July, Griffin was asked about the status of NASA's advanced space propulsion research. His reply referred to the Variable Specific Impulse Magnetoplasma Rocket (Vasimir).

The Vasimir involves the injection of a gas such as hydrogen into an engine that turns it into a plasma. That plasma is then energised further using radio signals as it flows through the engine, a process controlled by electromagnetic waves from superconducting magnets. Accelerated and heated through this process the plasma is focused and directed as exhaust by a magnetic nozzle. Vasimir is many times more efficient than conventional chemical rockets and far less fuel is needed.

Griffin says that the next step for the Vasimir is to operate it in space and that "we are at the end stages of agreeing a co-operative agreement for NASA to test the Vasimir engine on station".

The Vasimir engine taken to the ISS would be a scale-model test engine. Griffin says he does not know whether that scale-model engine would be launched by a Space Shuttle and would not give a timescale for Vasimir's possible deployment to the ISS.

The agency signed an agreement in 2006 to co-operate on Vasimir with the Texas based-Ad Astra Rocket corporation. Vasimir was originally conceived by Ad Astra Rocket chief executive and former NASA astronaut Franklin Chang-Díaz.