Kosmos 2421 (Cosmos 2421) was a Russian spy 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 LC90 at Baykonur. [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 junk 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]