Whatever the approach, aerospace traffic management "is getting to be a hot topic," says Ben Baseley-Walker, a consultant for the Secure World Foundation, a space-policy think tank based in Superior, Colo. Meetings on the subject that drew a few dozen academics two or three years ago are now drawing crowds of nearly 200 from around the world, he says. And several of the newer attendees are wearing military uniforms.
The reason: As more countries get into the space game, more spacecraft – manned and unmanned – will flit around Earth. "Increases in activity lead to increases in objects, and, therefore, increases in space debris. It's not a question of if, but when," says Mr. Baseley-Walker.
Close to Earth, a crowd
Outer space may be big, but the regions around Earth where satellites or humans can linger are relatively few. Low earth orbit, sun-synchronous orbits, and geosynchronous orbits are the current hot spots. And within those broad categories, there are preferred locations. Even at the moon, things are getting busy. In October, NASA is scheduled to send its Lunar Reconnaissance Orbiter to the moon, where it will join a lunar satellite from China and three from Japan. Earlier this week, NASA announced it was interested in setting up international science "nodes" on the moon – research platforms or vehicles that eventually could be linked via a moon-orbiting communications satellite.
Back around Earth, space junk – from paint flecks to chunks of spent rocket stages – share orbital space with satellites, the shuttle, the space station, and, eventually, any privately financed space stations and orbital space tourists.
Then there are the prospect of hybrids: Suborbital tourist flights and intercontinental transport that flirt with space as they travel. These will add their own unique air and space traffic issues.