2009 satellite collision

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Replica of an Iridium satellite Iridium satellite replica.jpg
Replica of an Iridium satellite
Digital painting of a Strela-2M satellite Strela-2M.jpg
Digital painting of a Strela-2M satellite

On February 10, 2009, two artificial satellites, Iridium 33 and Kosmos-2251, accidentally collided at a speed of 11,700 m/s (26,000 mph; 42,000 km/h) and an altitude of 789 kilometres (490 mi) above the Taymyr Peninsula in Siberia. [1] [2] [3] [4] [5] [6] It was the first time a hypervelocity collision occurred between two satellites – until then, all accidental hypervelocity collisions had involved a satellite and a piece of space debris. [7]

Satellite Human-made object put into an orbit

In the context of spaceflight, a satellite is an artificial object which has been intentionally placed into orbit. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as Earth's Moon.

Iridium 33 Communications satellite operated by Iridium Communications

Iridium 33 was a communications satellite launched by the United States for Iridium Communications. It was launched into low Earth orbit from Site 81/23 at the Baikonur Cosmodrome at 01:36 GMT on 14 September 1997, by a Proton-K carrier rocket with a Block DM2 upper stage. It was operated in Plane 3 of the Iridium satellite constellation, with an ascending node of 230.9°.

Taymyr Peninsula peninsula

The Taymyr Peninsula is a peninsula in the Far North of Russia, in the Siberian Federal District, that forms the northernmost part of the mainland of Eurasia. Administratively it is part of the Krasnoyarsk Krai Federal subject of Russia.



Kosmos-2251 was a 950-kilogram (2,094 lb) Russian Strela military communications satellite owned by the Russian Space Forces. [8] It was launched on a Russian Cosmos-3M carrier rocket on June 16, 1993. [2] It had been deactivated prior to the collision, and remained in orbit as space debris. Iridium 33 was a 560-kilogram (1,235 lb) commercial US-built satellite and was part of the Iridium constellation of 66 communications satellites owned by Iridium Communications. [2] It was launched on September 14, 1997, atop a Russian Proton rocket.

Strela is a Russian military communications satellite constellation operating in low Earth orbit.

Communications satellite artificial satellite designed for telecommunications

A communications satellite is an artificial satellite that relays and amplifies radio telecommunications signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth. Communications satellites are used for television, telephone, radio, internet, and military applications. There are 2,134 communications satellites in Earth’s orbit, used by both private and government organizations. Many are in geostationary orbit 22,200 miles (35,700 km) above the equator, so that the satellite appears stationary at the same point in the sky, so the satellite dish antennas of ground stations can be aimed permanently at that spot and do not have to move to track it.

Russian Space Forces branch of the Russian military

The Russian Space Forces are a branch of the Russian Aerospace Forces, that provides aerospace warning, air sovereignty, and protection for Russia. Having been reestablished following the 1 August 2015 merger between the Russian Air Force and the Russian Aerospace Defence Forces after a 2011 dissolving of the branch. The Russian Space Forces were originally formed on the 10 August 1992 and the creation of the Russian Armed Forces. The organisation shared control of the Baikonur Cosmodrome with the Russian Federal Space Agency. It also operated the Plesetsk and the Svobodny Cosmodromes. However the Russian Space Forces were dissolved in July 1997 and incorporated into the Strategic Missile Troops.


Collision diagram Collision iridium33 kosmos2251.jpg
Collision diagram

The collision occurred at 16:56 UTC and destroyed both the Iridium 33 and Kosmos-2251. The Iridium satellite was operational at the time of the collision. Kosmos-2251 had gone out of service in 1995. [9] It had no propulsion system, [10] and was no longer actively controlled. [11] [12]

Coordinated Universal Time Primary time standard by which the world regulates clocks and time

Coordinated Universal Time is the primary time standard by which the world regulates clocks and time. It is within about 1 second of mean solar time at 0° longitude, and is not adjusted for daylight saving time. In some countries where English is spoken, the term Greenwich Mean Time (GMT) is often used as a synonym for UTC and predates UTC by nearly 300 years.

Several smaller collisions had occurred previously, during rendezvous attempts or the intentional destruction of a satellite, including the DART satellite colliding with MUBLCOM, [13] and three collisions involving the manned Mir space station, during docking attempts by Progress M-24, Progress M-34, and Soyuz TM-17, [14] but these were all low-velocity collisions. In 1996, the Cerise satellite collided with space debris. [15] There have been eight known high-speed collisions in all, most of which were only noticed long after they occurred. [16]

MUBLCOM communications satellite

The Multiple Paths, Beyond-Line-of-Sight Communications (MUBLCOM) satellite, built for the Pentagon's Defense Advanced Research Projects Agency, was launched in May 1999 by a Pegasus rocket. Its mission was to demonstrate a capability to provide space-based digital voice and data communications to combat forces or commercial users that were previously considered out of range of standard radio communications systems.

<i>Mir</i> Soviet/Russian space station that operated in Earth orbit from 1986 to 2001

Mir was a space station that operated in low Earth orbit from 1986 to 2001, operated by the Soviet Union and later by Russia. Mir was the first modular space station and was assembled in orbit from 1986 to 1996. It had a greater mass than any previous spacecraft. At the time it was the largest artificial satellite in orbit, succeeded by the International Space Station (ISS) after Mir's orbit decayed. The station served as a microgravity research laboratory in which crews conducted experiments in biology, human biology, physics, astronomy, meteorology, and spacecraft systems with a goal of developing technologies required for permanent occupation of space.

Progress M-24 was a Russian unmanned cargo spacecraft which was launched in 1994 to resupply the Mir space station; causing minor damage to the station as the result of a collision during a failed attempt to dock.


Flashes created by the tumbling main body of the Iridium 33 wreckage. Iridium33 flashes.jpg
Flashes created by the tumbling main body of the Iridium 33 wreckage.
The collision resulted in significant debris in low Earth orbit. SpaceDebrisHistogram.png
The collision resulted in significant debris in low Earth orbit.

U.S. space agency NASA estimated that the satellite collision created approximately 1,000 pieces of debris larger than 10 centimeters (4 inches), in addition to many smaller ones. [17] By July 2011, the U.S. Space Surveillance Network had cataloged over 2000 large debris fragments. [18] NASA determined the risk to the International Space Station, which orbits about 430 kilometres (270 mi) below the collision course, to be low, [8] [19] as was any threat to the shuttle launch (STS-119) then planned for late February 2009. [8] However, Chinese scientists have said that the debris does pose a threat to Chinese satellites in Sun-synchronous orbits, [20] and the ISS did have to perform an avoidance maneuver due to collision debris in March 2011. [18]

NASA space-related agency of the United States government

The National Aeronautics and Space Administration is an independent agency of the United States Federal Government responsible for the civilian space program, as well as aeronautics and aerospace research.

The United States Space Surveillance Network detects, tracks, catalogs and identifies artificial objects orbiting Earth, e.g. active/inactive satellites, spent rocket bodies, or fragmentation debris. The system is the responsibility of the Joint Functional Component Command for Space, part of the United States Strategic Command (USSTRATCOM).

International Space Station Habitable artificial satellite in low Earth orbit

The International Space Station (ISS) is a space station, or a habitable artificial satellite, in low Earth orbit. Its first component was launched into orbit in 1998, with the first long-term residents arriving in November 2000. It has been inhabited continuously since that date. The last pressurised module was fitted in 2011, and an experimental inflatable space habitat was added in 2016. The station is expected to operate until 2030. Development and assembly of the station continues, with several new elements scheduled for launch in 2019. The ISS is the largest human-made body in low Earth orbit and can often be seen with the naked eye from Earth. The ISS consists of pressurised habitation modules, structural trusses, solar arrays, radiators, docking ports, experiment bays and robotic arms. ISS components have been launched by Russian Proton and Soyuz rockets and American Space Shuttles.

By December 2011, many pieces of debris were in a steady orbital decay towards Earth, and expected to burn up in the atmosphere within one or two years. By January 2014, 24% of the known debris had decayed.[ citation needed ] In 2016, Space News listed the collision as the fourth biggest fragmentation event in history, with Iridium 33 producing 628 pieces of cataloged debris, of which 364 pieces of tracked debris remain in orbit as of January 2016. [21]

A small piece of Cosmos 2251 satellite debris safely passed by the International Space Station at 2:38 am EDT, Saturday, March 24, 2012, at a distance of approximately 120 m (130 yd). As a precaution, the six crew members on board the orbiting complex took refuge inside the two docked Soyuz rendezvous spacecraft until the debris had passed. [22]

A number of reports of phenomena in the US states of Texas, Kentucky, and New Mexico were attributed to debris from the collision in the days immediately following the first reports of the incident in 2009, [23] although NASA and the United States Strategic Command, which tracks satellites and orbital debris, did not announce any reentries of debris at the time [24] and reported that these phenomena were unrelated to the collision. [25] On February 13, 2009, witnesses in Kentucky heard sonic booms. [26] The National Weather Service issued an information statement alerting residents of sonic booms due to the falling satellite debris. [27] The Federal Aviation Administration also released a notice warning pilots of the re-entering debris. [28] Some reports include details that point to these phenomena being caused by a meteoroid shower. [24] A very bright meteor over Texas on February 15, 2009, was mistaken for reentering debris. [29]


Events where two satellites approach within several kilometers of each other occur numerous times each day. Sorting through the large number of potential collisions to identify those that are high risk presents a challenge. Precise, up-to-date information regarding current satellite positions is difficult to obtain. Calculations made by CelesTrak had expected these two satellites to miss by 584 meters. [30]

Planning an avoidance maneuver with due consideration of the risk, the fuel consumption required for the maneuver, and its effects on the satellite's normal functioning can also be challenging. John Campbell of Iridium spoke at a June 2007 forum discussing these tradeoffs and the difficulty of handling all the notifications they were getting regarding close approaches, which numbered 400 per week (for approaches within 5 km) for the entire Iridium constellation. He estimated the risk of collision per conjunction as one in 50 million. [16]

This collision and numerous near-misses have renewed calls for mandatory disposal of defunct satellites (typically by deorbiting them or at minimum sending them in graveyard orbit), but no such international law exists yet. Nevertheless, some countries have adopted such a law, such as France in December 2010. [31] The United States Federal Communications Commission (FCC) requires all geostationary satellites launched after March 18, 2002, to commit to moving to a graveyard orbit at the end of their operational life. [32]

See also

Related Research Articles

Space debris collection of defunct objects in orbit

Initially, the term space debris referred to the natural debris found in the solar system: asteroids, comets, and meteoroids. However, with the 1979 beginning of the NASA Orbital Debris Program, the term also refers to the debris from the mass of defunct, artificially created objects in space, especially Earth orbit. These include old satellites and spent rocket stages, as well as the fragments from their disintegration and collisions.

Kosmos is a designation given to a large number of satellites operated by the Soviet Union and subsequently Russia. Kosmos 1, the first spacecraft to be given a Kosmos designation, was launched on 16 March 1962.

The Space Fence is a second-generation space surveillance system currently being built by the US Air Force in order to track artificial satellites and space debris in Earth orbit.

2009 in spaceflight spaceflight-related events during 2009

Several significant events in spaceflight occurred in 2009, including Iran conducting its first indigenous orbital launch, the first Swiss satellite being launched and New Zealand launching its first sounding rocket. The H-IIB and Naro-1 rockets conducted maiden flights, whilst the Tsyklon-3, Falcon 1 and Ariane 5GS were retired from service. The permanent crew of the International Space Station increased from three to six in May, and in the last few months of the year, Japan's first resupply mission to the outpost, HTV-1, was conducted successfully.

Kosmos 1818 was a nuclear powered Soviet surveillance satellite in the RORSAT program, which monitored NATO vessels using radar. Kosmos 1818 was the first satellite to use the TOPAZ-1 fission reactor. In July 2008, the satellite was damaged, and leaked a trail of sodium coolant.

Kosmos 1867 is a nuclear powered radar ocean reconnaissance satellite (RORSAT) that was launched by the Soviet Union on July 10, 1987. It was put into an orbit of about 800 km (500 mi). Its mission was to monitor the oceans for naval and merchant vessels, and had a mission life of about eleven months.

Kosmos 2251 Russian Strela-2M satellite

Kosmos-2251,, was a Russian Strela-2M communications satellite. It was launched into Low Earth orbit from Site 132/1 at the Plesetsk Cosmodrome at 04:17 UTC on 16 June 1993, by a Kosmos-3M carrier rocket. The Strela satellites had a lifespan of 5 years, and the Russian government reported that Kosmos-2251 ceased functioning in 1995. Russia was later criticised by The Space Review for leaving a defunct satellite in a congested orbit, rather than deorbiting it. In response, Russia noted that they were not required to do so under international law. In any case, the KAUR-1 satellites had no propulsion system.

Strictly speaking, a satellite collision is when two satellites collide while in orbit around a third, much larger body, such as a planet or moon. This definition can be loosely extended to include collisions between sub-orbital or escape-velocity objects with an object in orbit. Prime examples are the anti-satellite tests by the USA and China.

Iridium satellite constellation satellite constellation providing voice and data coverage

The Iridium satellite constellation provides L-band voice and data coverage to satellite phones, pagers and integrated transceivers over the entire Earth surface. Iridium Communications owns and operates the constellation, additionally selling equipment and access to its services. It was originally conceived by Bary Bertiger, Raymond J. Leopold and Ken Peterson in late 1987 and then developed by Motorola on a fixed-price contract from July 29, 1993 to November 1, 1998, when the system became operational and commercially available.

Kosmos 10, also known as Zenit-2 #5, was a Soviet reconnaissance satellite launched in 1962. It was the tenth satellite to be designated under the Kosmos system, and the fourth successful launch of a Soviet reconnaissance satellite, following Kosmos 4, Kosmos 7 and Kosmos 9.

Kosmos 2479 is a Russian US-KMO missile early warning satellite which was launched in 2012 as part of the Russian Aerospace Defence Forces' Oko programme. The satellite is designed to identify missile launches using infrared telescopes. It was the last US-KMO geostationary satellite, to be launched, prior to the system being replaced by EKS.

Kosmos 2480 Russian spy satellite

Kosmos 2480 is a Russian Kobalt-M reconnaissance satellite which was launched in 2012 by the Russian Aerospace Defence Forces. It was the last launch of a Soyuz-U rocket launched from Plesetsk Cosmodrome.

Kosmos 2478 is a Russian military satellite launched in 2011 as part of the GLONASS satellite navigation system.

Kosmos 2474 is a Russian military satellite launched in 2011 as part of the GLONASS satellite navigation system.

Kosmos 2421 was a Russian spy satellite launched in 2006, but began fragmenting in early 2008. It also had the Konus-A gamma-ray burst experiment by the Yoffe FizTekh Institute. Three separate fragmentation events produced about 500 pieces of trackable debris, but about half of those had already re-entered by the fall of 2008.

Kosmos 2494

Kosmos 2494 is a Russian military satellite launched in 2014 as part of the GLONASS satellite navigation system.

Kosmos 2500

Kosmos 2500 is a Russian military satellite launched in 2014 as part of the GLONASS satellite navigation system. It was the 2,500th satellite to receive a Kosmos designation


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