Possible, certainly. The real question is, how likely such collisions are. Many things are possible (e.g. you getting hit by a falling meteorite) but are ignored as too unlikely.
Collisions between satellites are indeed unlikely, but their likelihood increases rapidly with the number of satellites: increase the number of satellites 10 times and, other things being equal, the likelihood of collision grows 100-fold.
It all depends on the orbits of course. Most satellites move in low-altitude Earth orbit, 600-1000 kilometer above the ground. At any times, this space is filled by thousands of pieces of matter–satellites, rocket stages, cast-off pieces of hardware (like weights used to slow down satellite spin), etc., about 100,000 pieces, most of them fragments from exploding rockets, but also including some 7500 larger accountable pieces of space hardware. Space is huge, but all these are moving rapidly. Luckily, all motions are essentially in the same direction (west to east, chosen to take advantage of the Earth’s rotation) with almost the same speed. Even so, that speed is enormous, and collisions still may occur, since the orbits make different angles with the Earth’s equator.
So far, the problem is not serious. One definite collision has been recorded in July 1996. The French satellite Cerise, launched in 1995, collided with debris from a 1986 launch, and broke off a stabilizing boom. In this case it was soon noted that the satellite had lost orientation and control was reestablished. Fine grains of debris occasionally hit the space shuttle, leaving impact marks in the heat tiles and even in the windows; to avoid damage to the sensitive front of the shuttle, at times when no reason exists to do otherwise, it flies tail-first. A “ding” 1/16 inch across, in a window of the shuttle, may be seen here.
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and now …
Russian and US satellites collide
US and Russian communications satellites have collided in space in what is thought to be the biggest incident of its kind to date.
The US commercial Iridium spacecraft hit a defunct Russian satellite at an altitude of about 800km (500 miles) over Siberia on Tuesday, Nasa said.
The risk to the International Space Station and a shuttle launch planned for later this month is said to be low.
The impact produced a cloud of debris, which will be tracked into the future.
Since the Soviets launched Sputnik in 1957, it is estimated about 6,000 satellites have been put in orbit.
Satellite operators are all too aware that the chances of a collision are increasing.
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