The dots on this NASA-generated chart represent known pieces of large orbital debris.
The dots on this NASA-generated chart represent known pieces of large orbital debris. NASA

NASA has been tracking a piece of space junk on course for a near collision with the International Space Station this week, but while the agency continues to monitor the debris — a leftover from China’s brilliant shooting down of the Fengyun 1C weather satellite during a missile test in 2007 — Russian Flight Control authorities have issued an all-clear, saying an avoidance maneuver will not be necessary.

This month, NASA’s Orbital Debris Program Office released data naming the top ten incidents contributing to the space junk problem. The Fengyun fiasco is hands down the largest single contributor to the growing space junk crisis. NASA has identified some 19,000 objects larger than four inches that are running loose in orbit at extremely high rates of speed just waiting for a functioning satellite, a spacecraft, or the ISS to get in their paths. Of those, 2,841 are thought to have come from the destruction of Fengyun 1C.

Most of the garbage hurtling through space belongs to China and the Soviet Union, the report says, though Western commercial interests and space agencies also shoulder their shares of the blame. Some of the blame can even be divvied up; last year an operational Iridium communications satellite collided with a spent Russian Cosmos spacecraft, spawning nearly 2,000 pieces of smaller debris.

But Europe could soon take the top spot on the space junk tally. When the European Space Agency’s Envisat Earth observation satellite goes defunct in three years, the ESA will be the proud owner of the largest and most dangerous piece of junk out there: a nearly 9-ton, $2.9 billion piece of orbiting detritus that won’t be pulled into Earth’s atmosphere for 150 years. The danger isn’t that the massive satellite might slam into the ISS — the chances of that are quite slim. But if it collides with another large piece of junk at high speed — say, a rocket stage or another retired satellite — the impact could release 10 times as much junk as the Iridium-Cosmos smash up.

With so much junk up there, the DoD has even warned of a scenario in which such a massive collision could trigger a cataclysmic chain reaction in which one impact begets another and then another until entire orbits are unusable. Unlikely, sure, but some insist it’s possible. The good news is we’re working on the problem. Northrop Grumman is working with DARPA to develop a ground-based radar system to help track space debris from the ground, and the U.S. Air Force is planning to launch a Space-Based Space Surveillance satellite in the near future that will help direct traffic in space. Assuming, of course, a piece of orbiting junk doesn’t knock it clean out of the sky.

[Space, Network World, Voice of Russia]