Can satellites collide? Yes they can

First satellite launched in space was famous Sputnik, back in 1957. Since that time another 6000 satellites were also launched in space. Up until now we haven't heard any news about the possible satellite collision in space. Up until now that is because NASA admitted that The US commercial Iridium spacecraft hit a defunct Russian satellite at an altitude of about 800km (500 miles) over Siberia on Tuesday, 12th February 2009. The impact of this collision was cloud of debris, which will be tracked into the future. Scientists hope that most of debris will fall to Earth and burn up in the atmosphere because debris can also pose a risk to the ISS (international Space Station), which is orbiting the Earth some 435km below the course of the collision. According to NASA risk to the ISS is "very small and within acceptable limits".

Satellite collisions have happened eight times so far. Result of these collisions are clouds of debris.

This is not the first time such collision happened, and according to NASA spokesman John Yembrick this had happened on just eight previous occasions during the course of its 60,000-plus orbits. Of course as there are more and more satellites in space chances for collision are much bigger. Hubble Space Telescope and Earth-observing satellites at higher orbits and closer to the collision site were also at greater risk of damage.

6000 satellites have been sent to space in the last 50 years of which half of them are still operational. With an increased number of satellites in space there is also an increased chance of collision, and according to Nicholas Johnson, an orbital debris expert at the Johnson Space Center in Houston "at the beginning of this year there were about 17,000 manmade pieces of debris were orbiting Earth". There could be a lot more manmade debris in years to come.