Aviation Week & Space Technology, 11/03/2008 , page 20
Edited by Frank Morring, Jr.
A plasma rocket engine that may one day get a test on the International Space Station has reached a power milestone in one of the radio-frequency (RF) systems used to heat the electrically charged fluid that serves as a propellant. The Variable Specific Impulse Magnetoplasma Rocket (Vasimr), under development by Houston-based Ad Astra Rocket Co., reached its target rating of 30 kw. in a test of the RF device that generates the core plasma. The Oct. 22 test, which used argon as the propellant, sets the stage for integration of the 170-kw. unit that accelerates the core plasma and ejects it to provide thrust. The test required proprietary algorithms to control plasma stability during startup, according to Franklin Chang-Diaz, the seven-time shuttle astronaut who started work on the concept while at NASA and later founded Ad Astra. The Texas company is teamed with Nautel Ltd. of Halifax, Nova Scotia, which is developing the RF generators needed for both stages. The Vasimr engine uses RF energy to heat the plasma to extreme temperatures for high fuel efficiency, shielding the engine structure from the superhot gas with magnetic fields. Chang-Diaz has proposed placing a 1,128-kg. (2,482-lb.), 25-kw. Vasimr testbed on the ISS, and the company reportedly is negotiating details of an in-orbit trial with NASA.
Thanks Jaro for posting this update--I feel that VASIMR will likely be the primary candidate engine that will enable human beings to eventually explore beyond the orbit of the asteroid belt. It's the only thing that can deliver the exhaust speed needed to send crewed vehicles on such far flung voyages as the outer gas giants: Saturn, Uranus, and Neptune.
Dr. Franklin Ramon Chang-Diaz's engine has been in development since he published the original concept back in about 1979...I hope his engine gets a chance to be used as a reboost pallet installed on the ISS.
