As for weapons that will actually reside in space, as opposed to just passing through it, perhaps the most feasible and economical, at least in the short term, are microsatellites. (A microsatellite is simply any satellite weighing about 100 kilograms, or 220 pounds. Full-size satellites typically weigh at least 10 times that much.) Two programs are paving the way for such devices, which could one day conduct offensive military missions in orbit. Just a few days before the DART fender bender, the Air Force Research Laboratory launched a microsatellite known as Experimental Spacecraft System 11, or XSS-11. The clumsy DART experiment didn't bode well for the long-term success of XSS-11, which was also designed to conduct prox ops in orbit. "If we touch another object, we fail," says XSS-11 program manager Vernon Baker. First on the schedule was a rendezvous with the spent upper stage of the Minotaur rocket that carried the microsatellite into space. That was successful, and XSS-11 will spend more than a year visiting other objects in space.
Meanwhile, DARPA is working on a program called Orbital Express, in which a prototype servicing satellite will rendezvous with a prototype serviceable satellite in orbit to prove that the two can dock autonomously. Orbital Express, which is scheduled for a September 2006 launch, will also demonstrate on-orbit refueling.
Put XSS-11 and Orbital Express together, and you get a host of potential applications. Imagine a microsat that could fly up to a larger satellite and perform on-the-spot parts replacements and upgrades. Microsats could even be used as "bodyguards" for other satellites. "If you had multiple ones of these, you could basically make a fence," Baker says. The Air Force doesn't like to talk about offensive applications, but they aren't hard to imagine. "One of the most effective threats is a microsatellite in the form of a 'space mine,' " warned Richard L. Garwin, a prominent national-security expert with the Council on Foreign Relations, at a 2003 conference on space weapons. Microsatellites make good antisatellite weapons because they can easily maneuver to within lethal range of a satellite and then sit there ready to explode on command.
A space mine wouldn't necessarily even have to explode to be effective. In fact, an explosion might scatter debris that could prove deadly to friendly satellites. Instead, a space mine could simply shut down a larger satellite by zapping its electronics with a burst of electromagnetic energy. A microsat capable of attaching itself to a larger satellite could even act as a parasite-disabling the satellite, tampering with it, or blocking its view.single page
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.