A rocket thruster no bigger than a penny may be the future of powering small satellites in space.
MIT reports that associate professor of aeronautics and astronautics at MIT, Paulo Lozano, has designed a device which is worlds away from typical satellite engine valve, pipes and heavy-duty tanks. Instead, the engine is a flat, compact square, covered with hundreds of microscopic tips which are stimulated by voltage. Once charged, the spiky tips emit streams of ions -- creating enough thrust to propel a satellite forward, as long as it is no larger than your average shoebox.
The final device design measures 1cm x 1cm, and is 2mm in thickness.
According to Lozano, the engines are small enough to allow several to become bolted on to a vehicle. It is not only moving an object forward that is possible; instead, the device could push a satellite to turn or roll.
The satellite engine was recently revealed at the American Institute of Aeronautics and Astronautics' Joint Propulsion Conference.
Today, over two dozen small satellites, called CubeSats, orbit Earth. Once in space, lacking propulsion systems, the "nanosatellites" are often left to spin in orbit, burning up in lower atmosphere. However, if propulsion systems are created, then CubeSats could potentially be used to clear up what is known as "space junk" -- propelling down to low atmospheres to burn up, acting as garbage collectors, or pulling retired satellites down to Earth.
Traditional propeller systems are too bulky for nanosatellites. However, Lozano's design adds very little in terms of weight. The microthruster is made of several layers of porous metal -- the top layer coated in 500 metallic tips -- and the bottom contains liquid plasma full of free-floating ions that allow thrust to be created.
An array of 500 tips produces 50 micronewtons of force -- an amount of thrust that could only support a small shred of paper when restricted by gravity, but is enough to propel a two-pound satellite in space.
The team dream about a future which includes a small satellite equipped with several microthrusters. When the vehicle needs to break out of orbit, onboard solar panels would give the thrusters enough charge to propel the satellite forward. Lozano also hopes that with further development, the microthrusters could eventually control larger vehicles.
"Just like solar panels you can aim at the sun, you can point the thrusters in any direction you want, and then thrust," Lozano says. "That gives you a lot of flexibility. That's pretty cool."
Image credit: MIT/M. Scott Brauer