U.S. Satellite Destroyed in Space Collision
Washington - US Satellite Destroyed in Space Collision - Iridium Satellite LLC confirmed today that one of its satellites was destroyed Tuesday in an unprecedented collision with a spent Russian satellite and that the incident could result in limited disruptions of service.
According to an e-mail alert issued by NASA today, Russia's Cosmos 2251 satellite slammed into the Iridium craft at 11:55 a.m. EST (0455 GMT) over Siberia at an altitude of 490 miles (790 km). The incident was observed by the U.S. Defense Department's Space Surveillance Network, which later was tracking two large clouds of debris.
This is the first time we've ever had two intact spacecraft accidentally run into each other, said Nicholas Johnson, chief scientist of NASA's Orbital Debris Program Office at the Johnson Space Center in Houston. It was a bad day for both of them.
The space collision appears to be the worst space debris event since China intentionally destroyed one of its aging weather satellites during a 2007 anti-satellite test, Johnson told SPACE.com. That 2007 event has since left about 2,500 pieces of debris in Earth orbit, but more time is needed to pin down the extent of Tuesday's satellite collision, he added.
We're tracking more than 500 pieces of debris which pose an additional risk to satellites, said U.S. Navy Lt. Charlie Drey, a spokesperson for the U.S. Strategic Command which oversees the U.S. Space Surveillance Network. In a prepared statement, the Bethesda, Md.-based Iridium characterized the incident as a very low probability event and said it was taking immediate action to minimize any loss of service. Iridium, which operates a constellation of 66 low Earth-orbiting satellites providing mobile voice and data communications globally, said its system remains healthy and that it would implement a network solution by Friday.
Within the next 30 days, Iridium expects to move one of its in-orbit spare satellites into the network constellation to permanently replace the lost satellite, the statement said. The 1,234-pound (560-kg) Iridium 33 satellite involved in the collision was launched in 1997; the 1,984-pound (900-kg) Russian satellite was launched in 1993 and presumed non-operational. It did not have a maneuvering system, NASA said. Iridium's spacecraft circled the Earth along a near-polar orbit once every 100 minutes and flew at a speed of about 16,832 mph (27,088 kph), the company states on its Web site.