From a military perspective, the beauty of such weapons is that an enemy might not even know they're there. Microsatellites can be launched as secondary payloads on unrelated missions. And in the future, even smaller satellites-nanosats, weighing only around 22 pounds-will be able to do the kind of proximity and docking operations planned for today's microsats. It would be especially difficult to detect nanosats in geosynchronous orbits, 20,000 miles above the Earth, where many communications satellites are located.
Of course, the same advantages will apply to our opponents should they develop similar technology. One of the nations most interested in small satellites is China, which launched its first microsat, Tsinghua-1, in 2000. China has partnered with Surrey Satellite Technology, a British company at the forefront of microsatellite development, to field maneuverable microsats. Like XSS-11, these Chinese microsats are being developed for peaceful purposes but may be able to switch seamlessly to playing offense. From the ground, it would be difficult to tell the difference between a scientific microsat and a space mine.
Tracking such threats will be critical to waging an effective war in space, which is why the Air Force plans to launch a satellite called Pathfinder as early as 2008. Like other spy satellites, Pathfinder is basically a high-powered telescope. But rather than scanning objects on the ground, Pathfinder will examine other objects in space to identify any debris or foreign satellites that pose a risk to U.S. spacecraft. Eventually, a constellation of spysats-collectively known as the Space-Based Space Surveillance system-could join Pathfinder, gathering intelligence.
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.