A typical satellite is a dumb brute, heavy as a VW Bug and capable of performing only a single task. But a new breed, called microsatellites, are one-tenth that size as well as cheaper to build and launch. Clusters of microsats circling the globe can tackle different duties by changing their position relative to one another, but lack of room for extra fuel can be a problem.
Cannibalism may be the solution. Alok Das, an aerospace engineer with the Air Force Research Laboratory in Albuquerque, New Mexico, is designing a microsat that consumes its outer covering for fuel.
The microsat's surface is sturdy and relatively smooth, offering protection against multiple g-forces during a launch. But a tough outer covering is less important for a microsat in orbit. So Das decided that the surface should be made of silicon honeycombed with millions of tiny holes, each one-tenth of an inch deep and filled with a fuel source such as Teflon. When the microsat slips out of position, the Teflon in one of the holes is heated until it bursts out, creating a force that propels it back into formation. Each Teflon burst provides only a tiny push and can be used just once, but there are millions of them. "Your structural stiffness will go down," Das admits. "But then, you don't need it anyway." Das and his colleagues at the Aerospace Corporation and Honeywell Inc. expect the first such microsats will be launched in 2004.