Jan 23 2006
A new spacecraft ion engine designed by physicists at The Australian National University that dramatically improves performance over present technology has been successfully tested by the European Space Agency, it announced this month.
Ion engines work by accelerating a beam of positively charged particles (called ions) away from the spacecraft using an electric field, creating thrust.
“The engine, called DS4G, marks a major step forward in space propulsion capability, signalling the beginning of large scale robotic missions to the outer solar system and to the precursor interstellar medium,” said project leader Dr Orson Sutherland from the Space Plasma, Power and Propulsion (SP3) laboratory at ANU.
“A beam with an exhaust velocity of 210 kilometres a second was successfully fired from the engine during testing at the European Space Technology Centre in the Netherlands in November. This is four times faster than the current state of the art, making the system four times more efficient than what is presently achievable.”
The DS4G, first presented in 2001 by Dr David Fearn, a pioneer of ion propulsion, uses four accelerating grids instead of the usual three found on contemporary ‘gridded ion engines’ (GITs). The addition of this fourth electrode in an optimised configuration could make the DS4G concept up to ten times more efficient than the current state of the art, and allow the design of more compact and powerful thrusters.
The DS4G concept is very different to another type of thruster developed by the SP3 laboratory recently verified by the ESA. The Helicon Double Layer Thruster (HDLT) conceived at ANU by Dr Christine Charles in 2003 works by accelerating ions through a double layer without the need for electrodes.
“These two technologies are starkly different in their approach, but from our perspective they are complimentary to our overall aim of developing innovative thrusters for efficient deep space propulsion,” said Professor Rod Boswell, the head of the SP3 laboratory.
ANU was specifically contracted to design and build the DS4G because of its unique knowledge of the development of plasma ion sources, and its success with the development of the HDLT in collaboration with ESA. The new ion thruster was designed and manufactured from scratch in the extremely short time of four months by the project group which also included SP3 head technician Peter Alexander and electronics expert Dennis Gibson.
The contract to develop and test the DS4G was managed by Dr Roger Walker, a research fellow at the ESA's Advanced Concepts Team.
“Once developed into full flight ready devices, these engines will propel spacecraft to the outermost planets, the newly discovered planetoids beyond Pluto and yet further into the unknown realm beyond the solar system, all with-in the working lifetime of a mission scientist,” Dr Sutherland said. “Closer to home, these supercharged ion engines could figure prominently in the human exploration of space. With an adequate supply of electrical power, a small cluster of larger, high power versions of the new engine design would provide enough thrust to propel a crewed spacecraft to Mars and back.”