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A US Air Force satellite has exploded 500 miles above Earth's surface.
A 20-year-old US Air Force satellite has exploded in space, adding 43 pieces of space junk to Earth's orbit, reports have claimed.

The explosion happened on 3 February due to a sudden temperature spike, although the event has only just come to light.

However, talking to MailOnline, Nasa and Esa said the catastrophic event posed no significant risk to other satellites in Earth orbit.

The previously unknown incident was revealed by Space News, after posing questions to Air Force Space Command.

Known as the Defense Meteorological Satellite Program Flight 13 (DMSP-F13), it was launched back in 1995 and had remained in operation until now.

This made it the oldest continuously operational satellite in this particular series of satellites.

Exactly what has happened to the satellite, though, is still not clear, with the temperature strike remaining a mystery.

Air Force Space Command said the power subsystem experienced 'a sudden spike in temperature'.

This was followed by 'an unrecoverable loss of altitude control', before pieces of debris were then spotted in the vicinity of the satellite - suggesting it had partially, or completely, exploded.

Six other DMSP satellites are in orbit, while a seventh is scheduled to launch in 2016.

The Air Force played down the significance of the event, and said that the loss of the satellite - which had been retired to a back-up role - would not be detrimental to any of their operations.

'Because this satellite was no longer used by the National Weather Service or the Air Force Weather Agency, the impact of the loss of this satellite is minimal,' the Air Force told Space News.

'We anticipate real-time weather data for tactical users will be slightly reduced without this satellite, but its data was not being used for weather forecast modelling.'

However, the main fear from such an event is the increase in the amount of debris into Earth orbit.

Previous explosions in orbit, most notably the accidental collision of a US Iridium satellite and a defunct Russian Cosmos satellite in 2009, have released hundreds of pieces of debris into orbit.

Another notable event was a Chinese anti-satellite missile test in 2007, when they blew up one of their own satellites, which was widely condemned.

This raises the risk of a collision in future, and even the ISS occasionally has to perform manoeuvres to avoid space debris.

But speaking to MailOnline, Nasa and Esa played down the risk of any potential issue.

'If the reported fragment numbers are stable, then the event is not considered major,' said Dr Holger Krag, Head of Esa's Space Debris Office.

'What makes this event special is that the break-up obviously happened while the satellite was still operational.'

Dr Krag noted that the explosion occurred above 500 miles (800km), where few other satellites were in orbit.

Indeed, Esa's closest mission is Cryosat-2, at an altitude of 450 miles (720km), so Dr Krag said they 'do not expect any meaningful risk increase due to this event.'

Dr Eugene Stansbery, Program Manager of Nasa's Orbital Debris Program Office, added: 'The debris cloud from this event is obviously much smaller than the Chinese ASAT test of 2007 or the Iridium/Cosmos collision of 2009.

'We have collected additional measurements to more fully characterize the event, but the data has not been processed yet.

'Depending on what size you go down to, there are many thousands to millions of debris in orbit. This is a small increase to an existing risk to other spacecraft.'

US Strategic Command has not yet responded to a request from MailOnline regarding whether the defect that caused this satellite to blow up could affect other similar satellites.