An engine that dramatically outperforms all existing alternatives at the lab bench is set to be tested in space. In the week that Elon Musk announced plans to send humans to Mars, the news could be an important step towards making that vision real.
The Neumann Drive is an ion engine invented by Dr Patrick Neumann of the University of Sydney. It applies an electric arc to metals, ionizing the vapor produced and using an electric field to propel the ions to create thrust. Using magnesium, the most efficient metal he tried, Neumann achieved 50 percent more impulse than NASA’s High Power Electric Propulsion (HiPeP) – the previous record holder.
So far, Neumann’s work, recently published in Applied Physics Letters, is all laboratory based, but yesterday Airbus Defence and Space confirmed plans for a year-long test of the drive on the International Space Station (ISS), launching in 2018.
Provided Neumann’s engine performs as expected, it has the potential to make many sorts of space flight cheaper and easier. Ion thrusters do not provide nearly enough thrust to launch a craft into space, except from very low-gravity objects like small asteroids.
Once a craft is in space, however, they are very efficient, allowing satellites to maneuver or probes to voyage to other planets, for a fraction of the fuel of chemical rocket-powered vehicles. With the Neumann Drive being so much more efficient, it could make possible missions that are currently unaffordable.
Neumann's engine is designed for small satellites or probes to other planets, but his co-author Professor Marcela Bilek told IFLScience that “the system is quite compact and modular, so there is no reason you couldn't use multiple ones in parallel,” making it ideal for ships large enough to carry humans to the planets.
Bilek, in whose lab the prototype was built, said that much of the year since IFLScience first reported on Neumann's work has been taken up with negotiating to get the engine launched, but in the meantime the science has not stood still. “Now we understand why magnesium is the best fuel – back then we didn't know why it outperformed other light metals,” she said.
Magnesium's advantage is that it turns directly from a solid into an easy-to-ionize (make electrically charged) vapor, which can be fired backwards, providing forward thrust. Some other light metals melt instead, leaving liquid droplets that are of little use for these purposes.
Nevertheless, one of the great advantages of Neumann's machine is that it can use any metal, even if some are better than others. Future missions to asteroids, for example, could mine what they need for the return journey. Old satellites could be captured and put to use, reducing the threat of space junk in the process.
Bilek told IFLScience small modifications need to be made to the thruster before it is ready for launch, but these should easily be completed by mid-2017, with the launch set for December 2018.
