NASA's Jet Propulsion Laboratory (JPL) has successfully run an ion thruster for 30,352h - four times its design life - in an effort to observe long-term wear effects.
The engine, a spare from the Deep Space 1 technology demonstration mission, has been in operation since October 1998 at JPL in Pasadena, California, as part of the In-Space Propulsion Technology programme and has far surpassed its 8,000h design life. The test was prolonged to measure performance and wear at varying thrust levels and the results will be used to prioritise research and develop improved ion thrusters.
The test was halted because NASA missions using ion propulsion - such as Dawn, which will be launched in 2006 to orbit the asteroids Vesta and Ceres - need analysed data that require inspection of the engine components.
John Brophy, JPL's project element manager for the Dawn ion propulsion system, says the condition of the thruster's discharge chamber, where xenon gas is ionised, was particularly important. "Most of the components showed wear, but nothing that would have caused near-term failure," he says.
The ion engine on the Deep Space 1 spacecraft operated for a record 16,265h. Ion propulsion systems can run on just a few grammes of xenon gas a day, and although the thrust exerted is quite small, its fuel efficiency can reduce trip times and launch vehicle costs.
Source: Flight International
