National Geographic : 2010 Jul
THE BIG IDEA |SPACE TRASH ART: STEFAN MORRELL SOURCE: NASA ORBITAL DEBRIS PROGRAM OFFICE OTHER NASA SCIENTISTS worry about getting astronauts off the ground or sending interplan- etary probes to Pluto. Nicholas Johnson worries about a nightmare scenario called the Kessler syndrome, named for his colleague Donald Kessler, who first described it in the 1970s. The scenario begins in an overcrowded orbit. Two massive pieces of hardware---satellites, say, or spent booster rockets---slam together at more than 20,000 miles an hour, smashing each other into hundreds of pieces. One piece then collides with another spacecraft, creating hundreds more pieces---and so on in a slowly building chain reaction that culminates in a belt of space shrapnel too dense for anything to traverse safely. Until last year, says Johnson, chief scientist at NASA's Orbital Debris Program Office, "the danger was purely academic. " But on February 10, 2009, the world witnessed its first full-blown hyperveloc- ity crack-up. An Iridium communications satellite collided with a defunct The final frontier is littered with dead spacecraft and shrapnel. It's a hypervelocity menace. How can we clean it up? Clearing Space THREE IDEAS for clearing space of junk---including the debris of two satellites that collided in 2009---would speed the rate at which the debris falls into the atmosphere and burns. • (Continued on next page) COSMOS 2251 RUSSIA IRIDIUM 33 U.S.