Mini ion thrusters are manufactured using micro-manufacturing techniques. This image shows an example of the different parts comprising a thruster. The finalized device is at the bottom right, measuring 1 cm by 1 cm and 2 mm in thickness. Photo: M. Scott Brauer
A worry about the proliferation of CubeSat satellite launches is adding clutter to an already troublesome amount of Earth-circling debris.
If CubeSats were deployed at higher orbits, they would take much longer to degrade, potentially creating space clutter. As more CubeSats are launched farther from Earth in the future, the resulting debris could become a costly problem.
“These satellites could stay in space forever as trash,” says Paulo Lozano, an associate professor of aeronautics and astronautics at the Massachusetts Institute of Technology (MIT). This trash could collide with other satellites. “You could basically stop the Space Age with just a handful of collisions,” he suggests.
Today, more than two dozen CubeSats orbit Earth – each slightly bigger than a Rubik’s cube, and tip the scale at less than three pounds.
But now, an ultra-small rocket thruster could soon power the smallest of satellites in space. As small as a penny, these thrusters run on jets of ion beams.
The device, fabricated by Lozano, 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.
Switching directions
Lozano and his colleagues found that an array of 500 tips produces 50 micronewtons of force — an amount of thrust that, on Earth, could only support a small shred of paper. But in zero-gravity space, this tiny force would be enough to propel a two-pound satellite.
This new technology could enable CubeSats to propel down to lower orbits to burn up, or even act as space garbage collectors, pulling retired satellites down to degrade in Earth’s atmosphere.
The MIT researchers envision a small satellite with several microthrusters, possibly oriented in different directions. When the satellite needs to propel out of orbit, onboard solar panels would temporarily activate the thrusters.
In the future, Lozano predicts, microthrusters may even be used to power much larger satellites: Flat panels lined with multiple thrusters could propel a satellite through space, switching directions much like a rudder, or the tail of a fish.
“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.”
For a video clip on this work, go to:
By Leonard David via Jennifer Chu, MIT News Office