Soon, penny-sized thrusters to propel small satellites

          Scientists may soon be able to power the smallest satellites in space through penny-sized rocket thrusters instead of today's bulky satellite engines.
The device, designed by Paulo Lozano, an associate professor of aeronautics and astronautics at Massachusetts Institute of Technology is a flat, compact square much like a computer chip covered with 500 microscopic tips that, when stimulated with voltage, emit tiny beams of ions.
Together, the array of spiky tips creates a small puff of charged particles that can help propel a shoebox-sized satellite forward.
It bears little resemblance to today's bulky satellite engines, which are laden with valves, pipes and heavy propellant tanks.
"They're so small that you can put several [thrusters] on a vehicle," Lozano said.
He added that a small satellite outfitted with several microthrusters could not only move to change its orbit, but do other interesting things - like turn and roll.
More than two dozen small satellites, called CubeSats, orbit Earth today. Their diminutive size classifies them as nanosatellites.
But these small satellites lack propulsion systems, and once in space, are usually left to passively spin in orbits close to Earth. After a mission concludes, the satellites burn up in the lower atmosphere.
Lozano added if CubeSats were deployed at higher orbits, they would take much longer to degrade, potentially creating space clutter.
"These satellites could stay in space forever as trash," Lozano said in a statement.
Engineering propulsion systems for small satellites could solve the problem of space junk. CubeSats could propel down to lower orbits to burn up, or even act as galactic garbage collectors, pulling retired satellites down to degrade in Earth's atmosphere.
However, traditional propulsion systems have proved too bulky for nanosatellites, leaving little space on the vessels for electronics and communication equipment.
In contrast, Lozano's microthruster design adds little to a satellite's overall weight. The microchip is composed of several layers of porous metal, the top layer of which is textured with 500 evenly spaced metallic tips.
Lozano and his group presented their new thruster array at the American Institute of Aeronautics and Astronautics' recent Joint Propulsion Conference.