WASHINGTON (AFP) — A Russian and a US satellite crashed into each other in an unprecedented collision unleashing clouds of space debris that could threaten orbiting spacecraft, officials said.
A defunct Russian military satellite, Kosmos 2251, collided on Tuesday at 1655 GMT with a communications satellite owned by US-based Iridium Satellite LLC at about 500 miles (800 kilometers) above Siberia, said Major General Alexander Yakushin, deputy commander of Russia's space forces.
After more than five decades of human activity in space, the news raises fresh concern over the swarms of hazardous debris orbiting the Earth.
"My worry is that that debris field is going to be up there for about a year, so we're going to have to play a little bit of dodgeball for many tens of years to come," said General James Cartwright, vice chairman of the US Joint Chiefs of Staff.
"The good news is once it's stabilized, it's relatively predictable. The bad news is it's a large area," added Cartwright, the former head of the US Strategic Command (STRATCOM), whose Joint Space Operations Center tracks over 18,000 man-made objects orbiting the Earth.
The size of the debris clouds formed by the collision, the first hypervelocity impact between two intact spacecraft, will not be known for at least several weeks, NASA said.
"So far, NASA experts have determined that the risk to the Space Station is elevated. They estimate the risk to be very small and within acceptable limits," John Yembrick, a spokesman for the US space agency, told AFP.
"Although a small amount of debris will pass through the station's altitude, some over months, some over years, some over decades, we can track them and, in a worst case scenario, dodge the debris if necessary."
The International Space Station (ISS) orbits about 220 miles (354 kilometers) above the Earth, far below the point of collision.
But NASA's Hubble Space Telescope and Earth observation satellites travel at higher orbits and could risk more damage.
"NASA's Earth-observing satellites orbit at an altitude of approximately 439 miles (707 kilometers), which is not far from the 491-mile (790-kilometer) altitude of the collision. They are of the highest concern as NASA learns more about the newly-created debris field," Yembrick said.
Although "all satellites operating in or passing through low-Earth orbit potentially are at risk of being impacted, including at least 20 NASA satellites, the risk is considered very low."
NASA spokesman William Jeffs said there was no danger to the scheduled February 22 launch of the space shuttle Discovery to the ISS.
The Pentagon meanwhile acknowledged it had not anticipated the accident, citing "limits" on its ability to track thousands of man-made objects in space.
The debris from the collision could be significant.
"We are looking at around more than 500 pieces of debris," said STRATCOM spokesman Navy Lieutenant Charlie Drey.
"Anytime you have something like this happen, there is a concern about other objects that are in orbit. Now that you have all this debris there, it does pose a risk to satellites," he told AFP.
Analysts are plotting the coordinates of each of the debris pieces, which will later be posted on the website space-track.org.
In a statement, Iridium, which has 66 communications satellites, called the crash an "extremely unusual, very low-probability event," rejecting it was at fault.
A 2008 report by the international monitoring group Space Security Index found that 300,000 objects measuring between 0.4 and four inches (one and 10 centimeters) in diameter and "billions" of smaller pieces orbit the Earth.
Traveling at speeds that can reach many thousands of miles (kilometers) per hour, the smallest debris can damage or destroy a spacecraft.
In June 1983, the windscreen of the US space shuttle Challenger had to be replaced after it was chipped by a fleck of paint measuring 0.01 of an inch (0.3 millimeters) that impacted at 2.5 miles (four kilometers) per second.
Some 6,000 satellites have been sent into space since the Soviet Union launched the first man-made orbiter, Sputnik 1, in 1957. About 800 satellites remain in operation, according to STRATCOM.
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