The risk of collision between catalogued space objects - operating satellites and space debris larger than ten centimeters - has grown five times in the past 21 years, says a report from the Information Analytic Center of the NPO Almaz-Antei Vympel Interstate Joint Stock Corporation.
The corporation, a major link of Russia's space surveillance system, says, "The risk is the largest for the International Space Station (ISS) and the smallest for spacecraft deployed at an average orbit of 1,500 kilometers."
"The relatively large risk of ISS collisions is explained with its size (20 meters), which is one order of magnitude larger than the regular size of other spacecraft (one-two meters). If a one or two-meter object had been deployed on the level of the ISS, the probability of its collision would have been at least 200 times smaller than in the case of ISS, as the collision probability is proportionate to the square of its size," says the research.
"The probability of collision of target satellites, which are one or two meters in size, is the highest on the level of 800-1,000 kilometers. The collision of Iridium-33 and Cosmos-2251 happened precisely on February 10, 2009, on that level," the research authors said.
"Catalogued target satellites run a collision risk once every 1,000 years," they noted. In fact, the risk is much higher because "the real danger to target satellites is posed not only by catalogued objects, whose size regularly exceeds ten centimeters, but also by non-catalogued objects with a size exceeding one centimeter." If a one-centimeter object hits a satellite at an approach velocity of 11 kilometers per second, the satellite may be incapacitated or even destroyed.
"The number of non-catalogued objects with a size larger than one centimeter is about 100 times larger than the number of catalogued objects on the levels of operation of target satellites (800-1,700 kilometers). The probability of collision is approximately 100 times higher, as well, i.e. an event happens once every ten years on average," the researchers said.
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