2 defunct satellites narrowly avoid collision as they fly past each other

Two decommissioned satellites, an international space telescope and experimental US craft narrowly missed each other while travelling in opposite orbits. According to a spokesperson from US Space Command, the two satellites crossed each other's paths without incident. The risk of impact had been calculated by scientists to be between 1-5 per cent.

Same trajectory, opposite directions

While the chances of the two satellites colliding may have only been 1 to 5 per cent, the space community still considers this high chance of collision. The crashes between large satellites at extreme speeds is a rare occurrence and is considered very dangerous because the collision creates a cloud of debris that greatly endanger surrounding spacecraft in the vicinity.

The international space telescope called Infrared Astronomical Satellites (IRAS)  was launched in 1983. The mission was a joint operation between the US (NASA), Britain and the Netherlands. The satellite's mission lasted only 10 months. The space telescope reportedly weighs one tonne and as per the European Space Agency, it is about the size of a truck.

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On the other hand, the experimental US satellite is called GGSE-4 and was launched by the US Air Force in 1967 and weighs only 85 kilograms. The satellite has an unusual shape in that it is only around 60 centimetres in width but is 18 metres long and flies vertically.

If the satellites had collided with each other, it is believed that they would have created close to a thousand pieces of debris varying greatly in size. According to reports, there are approximately 20,000 pieces of debris that are bigger than a softball and are orbiting the planet and can reach speeds up to 28,000 kilometres per hour.

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