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Comment: Re:How is this new? (Score 5, Informative) 100

by hrshea (#39535839) Attached to: New Engine Raises Possibility of Cheap Travel To the Moon
This ion thruster is unique by its extremely small size. we have miniaturized not only the ion emitter, but the entire thruster including high-voltage electronics and tank. Our complete thruster has a mass of 200g (including 100 ml of fuel), thus allowing it to be used on nanosatellites. It is the first high efficiency electric propulsion system that can be used in cubesats and 5kg satellites, such as those being planned for OLFAR The principle of operation of colloid thruster a bit different from the ion engines used fro instance on SMART-1, which uses ionize Xenon. in our case, we use a particular conductive liquid, an ionic liquid, from which we can extract both positive and negative ions. using a liquid avoids a pressurized tank, and allows for important simplification of the system (no valves, no heavy tanks, all flow controlled by capillary and electrostatic forces. using the ionic liquid allows the same speed as using a gas, but offers one big advantage: since we emit (from 2 chips in parallel) both positive and negative ions, the spacecraft stays electrically neutral, which is essential for electric propulsion to avoid having the ions fly back to the spacecraft. for more conventional electric propulsion systems, only positive ions can be emitted, so a neutralizer is needed to emit electrons to keep the spacecraft charge neutral. not having a neutralizer allows significant mass and power savings.
I'm biased, 'cause I work on this!
http://lmts.epfl.ch/microthust
- Herb Shea

Comment: Re:From Where? (Score 5, Informative) 100

by hrshea (#39535729) Attached to: New Engine Raises Possibility of Cheap Travel To the Moon
As the lead author of the work, I'm happy to give you some more direct links EPFL press release: http://actu.epfl.ch/news/getting-to-the-moon-on-drops-of-fuel/ MicroThrust consortium: http://www.microthrust.eu/ EPFL research on micro propulsion: http://lmts.epfl.ch/microthrust

The propulsion system emits ions at high speed (40 km/s) and is thus very efficient at converting propellant mass to satellite momentum. Thrust is low, but given time, ver lge orbit chanegs are possible. for example, in order to reach lunar orbit from low-Earth orbit, a 3-kg nanosatellite with our motor would travel for about 2 years and consume about 500 grams of fuel" - Herb Shea

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