Two satellites came close to colliding in orbit Wednesday, highlighting the potential hazard posed by debris in space. The derelict Poppy VII-B and IRAS spacecraft made their closest approach – predicted to have been within 47 meters – at 23:39 UTC high above the US state of Pennsylvania. Had a collision occurred, it would have left a field of debris in low Earth orbit.
There has only been one accidental collision between two intact satellites in different orbits. This occurred eleven years ago, involving a then-operational satellite in the Iridium communications network and a defunct Russian communications satellite. In contrast, both of the satellites involved in Wednesday’s near-miss had been inactive for at least 36 years.
Poppy VII-B is a military satellite that was launched by the United States in the 1960s, weighing about 83 kilograms (183 pounds). The Infrared Astronomical Satellite (IRAS) is a retired scientific satellite, which conducted the first infrared all-sky astronomical survey in 1983. It had a mass at launch of 1,073 kilograms (2,366 lb).
The close approach between the two satellites occurred about 900 kilometers (559 miles, 486 nautical miles) above the United States, near the city of Pittsburgh. Had a collision occurred it would ...