Ionic MicroThrust (EPFL)
For unmanned probes on small budgets which can afford to wait several months to reach their destinations, EPFL laboratories in Lausanne, Switzerland, completed a prototype in April 2012 of an ultra compact and efficient electric engine called the MicroThrust, which uses an ionic liquid at room temperature, EMI-BF4. Weighing only a few hundred grams, including the fuel, and designed to mount within satellites as small as CubeSats (10 cm cube), its intentions are to economically boost and maneuver satellites, including interplanetary missions.
One of the first two missions for testing is planned to be CleanSpace One, a satellite also developed at EPFL which is intended to maneuver in low Earth orbit to clean up space debris.
The second mission is OLFAR, a swarm of Dutch nanosatellites which will pass by the far side of the Moon to record ultra low radio frequency signals.
Companies involved include the Dutch companies SystematIC Design B.V. and TNO, the Swedish company Nanospace AB, and Queen Mary and Westfield College in the UK.
The principles are similar to existing ion drive vehicles, but promise to extend the cost effectiveness.