Kosmos 2421 (Cosmos 2421) was a Russian reconnaissance satellite launched in 2006, but began fragmenting in early 2008.[1] It also had the Konus-A science payload designed by Ioffe Institute to detect gamma-ray bursts.[2] Three separate fragmentation events produced about 500 pieces of trackable debris.[1] About half of those had already re-entered Earth's atmosphere by the fall of 2008.[3]
Kosmos 2421 was launched on June 25, 2006, on a Tsyklon-2 from the Site 90/20 launch pad at Baikonur.[4] Other designations are 2006-026A and NORAD 29247.[4] It is a US-PU/Legenda type satellite, and was in a 65 degree, 93 minute circular orbit 410–430 km up.[4] The main body of the satellite finally re-entered and burned up on 19 August 2010.[5]
There have been 190 known satellite breakups between 1961 and 2006.[6] Kosmos 2421 was one of the top ten space debris producing events up to 2012.[7] There was estimated to be 500,000 pieces of debris in orbit at that time.[7]
On August 27, 2008, the International Space Station (ISS) fired the boosters of the Jules Verne automated transfer vehicle to avoid debris fragment 33246 from the remains of Kosmos 2421.[8] Without a change, that piece was predicted to have a 1 in 72 chance of hitting the station.[8] Kosmos 2421 had been in a higher orbit than ISS, so when ISS's apogee (high point of orbit) surpassed the debris field's perigee (low point of orbit), many fragments would cross ISS's orbit.[8]