Feeling the pinch at the pump lately? Just be glad your commute doesn’t require you to escape Earth’s gravity. Sending a space shuttle into orbit takes hundreds of thousands of gallons of fuel, and although satellites are smaller, they still require a ton of fuel to break through the atmosphere.
But what if all this propellant (and the steep price tag) wasn’t necessary? Switzerland’s Ecole Polytechnique Fédérale de Lausanne (EPFL) laboratories recently built a prototype motor that will allow small satellites to journey beyond Earth’s orbit using just a tenth of a liter of fuel. The secret is that the motor won’t burn fuel like traditional vehicles do. Instead of a combustible fuel, the new mini-motor runs on an “ionic” liquid, in this case the chemical compound EMI-BF4.
The ionic motor, dubbed MicroThrust, weighs only about 7 ounces, including the fuel and control electronics is specifically designed to propel small satellites (between about 2 and 440 pounds). If successful, MicorThrust could enable these satellites to change orbit around Earth and even voyage to more distant destinations—things that only large, expensive spacecraft can do now. “At the moment, nanosatellites are stuck in their orbits. Our goal is to set them free,” explained Herbert Shea, coordinator of the European MicroThrust project and director of EPFL’s Microsystems for Space Technologies Laboratory, in a recent release.
The “liquid” that gives MicroThrust its compact power is composed of electrically charged molecules (like ordinary table salt) called ions, except that this compound is liquid at room temperature. The ions are extracted from the liquid and then ejected by means of an electric field to generate thrust. This is the principle behind the ionic motor: fuel is not burned, it is expelled, propelling the object to which it is attached forward, quite quickly.
The just-released prototype is expected to employed on CleanSpace One, a satellite under development at EPFL that is designed to clean up space debris, and on OLFAR, a swarm of Dutch nanosatellites that will record ultra-low radio-frequency signals on the far side of the Moon.