MIT develops tiny ion thrusters for tiny satellites
Usually, when you think of space engines, you think of bus-sized rockets that propel massive spacecraft. But what you see in the above photo are actually a new type of penny-sized microthruster created by MIT.
As spotted by io9, these microthrusters are about the size of a microchip, and they emit a tiny beam of ions to generate thrust. While these tiny ion rockets probably won’t have enough power to move a regular-sized satellite, they could be just what we need to power an army of miniature satellites.
These microchip-sized thrusters are lined with an array of 500 microscopic tips. At the base of the chip is a “liquid plasma” reservoir of free-floating ions. In between these two layers are small pores that suck the ionic fluid up to the metallic tips through capillary action. Once the fuel reaches the surface of the device, the scientists apply a charge to the liquid using a gold-coated plate placed over the chip. This creates an electric field that causes the ions to be released through the tips.
The MIT researchers say that the small puff of charged particles from an array of 500 tips would produce 50 micronewtons of force. On Earth, this would be enough force to support a sheet of paper, but in space, it would enough to propel a two-pound satellite.
Today, there are about two-dozen small satellites, called CubeSats, in low orbit above Earth. They are just slightly larger than a Rubik’s cube and weigh less than three pounds. Thanks to their small size, these nanosatellites are cheaper to manufacture and easier to send into space than a full-size satellite. The only problem is: they don’t have a propulsion system, so the CubeSats are launched into low orbit above Earth to complete their mission and eventually fall back down to burn up in the atmosphere.
Scientists want to deploy these CubeSats into higher orbits, but this could lead to more space debris and collisions. With the addition of these tiny ion thrusters, though, the CubeSats could maneuver under their own power to better observe objects in space or push old space junk back towards Earth in a sort of space seppuku.