Over 521,000 pieces of junk are in orbit around Earth, each traveling up to 17,500 miles per hour (that's about 28,200 kilometers per hour). Which means that even the smallest of the bunch poses a danger to our satellites, spacecraft and astronauts. Although most space-faring objects are built to withstand minor impacts, even a crystal of astro-urine moving at that speed is a potential threat.
We've only begun to worry about space debris relatively recently, and it's looming larger than usual in the public consciousness thanks to Alfonso Cuarón's 2013 film "Gravity," as Jonathan discusses in our video How Do We Clean Up Space Junk?. As of the publication of this article, private companies and governmental agencies alike have methods for evading large pieces of space junk. Objects as small as three millimeters (that's some 0.12 inches) in diameter can be detected using ground-based radar, and some spacecraft can take evasive action when an impact is likely. But humanity has no "Spaceballs"-style Mega Maid to clean up our orbit.
Or, we don't quite yet. As we detailed in our podcast episode Space and Junk,* lots of researchers are working on the problem. Tune in to the video and audio episodes for snack-sized explanations, but if you're hungry for more, check out our sources:
Space.com collected a few great videos, and Wired has a whole series of articles covering space environmentalism, some of the kitsch in space, and specific solutions including ground-to-orbit lasers and static electricity 'tractor beams'. New Scientist has a great infographic explaining a not-quite-Mega-Maid-level janitor satellite. And the BBC reported on research about the potentially scary future of debris collisions.
We look forward to seeing whether any of these designs make it to the prototype stage - or, rather, which will make it there first. Which would you bet on?
*Hey, this episode was featured on Stitcher's top Brain-Food Fix list for the week of November 4, 2013! Thanks so much, Stitcher! Glad you had as much fun with this one as we did.