Outer space is becoming a garbage heap. Some 15,000 pieces of debris, ranging from fingernail-sized paint flecks to 10-ton rocket stages, are hurtling through Earth's orbit at 5 miles per second — about 10 times as fast as a speeding bullet. And the junk is multiplying, Asteroids-like, as large objects break apart into smaller ones. (China's recent anti-satellite test has hastened the process.) Scientists warn of an approaching Kessler syndrome: the point at which flotsam from collisions makes future space ventures dangerous. How can we clean up the mess? The trick is to either grab shrapnel or coax it toward the planet, where it will burn up in the atmosphere. Several methods of trash collection have been floated. Some are cleverly low tech; others seem like fodder for the Sci Fi Channel.
6 Ways to Clean Up Space
NASA already uses this superlight, polystyrene-like material to capture space dust for study. So, some scientists suggest, why not send massive, multipaned panels of aerogel into orbit to accumulate smaller pieces of space waste like bugs on a windshield? Once saturated with crap, the swaths of goo could be rocketed into the atmosphere.
Orbiting light cannons are possible but probably decades off (plus, there are diplomatic concerns). But scientists offer as a viable option ground-based lasers to disrupt the orbit of errant objects, causing them to plummet. Targeting would be handled by new supersensitive radar capable of tracking orbiting debris as small as 1 centimeter in diameter.
3. Collector Barge
Engineers at the Uni versity of Arizona propose that an unmanned barge use radar and cameras to home in on objects, then deploy robot arms to snatch them up. Once clutched, items could be decimated by gold-plated mirrors that focus sunlight. Unless, that is, the scraps are shiny, in which case they would be added to the reflective array.
4. Nets A system called Grasp (grapple, retrieve, and secure payload) would use a large, tightly meshed net strung between long, inflatable booms to ensnare objects. According to aerospace firm TUI, which is testing the system, a fleet of GRASP-equipped micro-satellites could fly into new debris clouds and trap the rubble before it wreaks additional havoc.
The fastest-growing category of debris is the small stuff — paint flecks, titanium bits, and other artifacts from collisions or explosions of large objects (such as rocket stages). NASA says a massive panel of highly porous foam (think Nerf football) could be placed in the path of a debris field. Junk passing through would quickly decelerate and fall to Earth.
Tethers of copper and other highly conductive materials could be installed on outgoing satellites or attached to older ones by delivery vehicles. Once unfurled, TUI's theory goes, they would react with Earth's electromagnetic field and become a sort of super conductive drag anchor, slowing an object until gravity pulled it into the inferno of reentry.