The European Space Agency has had to perform its first ever "collision avoidance manoeuvre" to avoid one of its satellites smashing into a "mega constellation".
One of the space agency's satellites was on a collision course with the constellation, which is made up of a vast number of internet satellites called Starlink that were put into space by Elon Musk's SpaceX.
Without the manoeuvre, the satellites could have collided high above Earth, ESA warned.
But such moves might not be possible in the future, it said. As more such constellations arrive in space, the danger will be vastly increased and will not be able to solved by manoeuvring out of the way.
The move was forced after ESA's experts in space debris found that there was a high risk of collision between the two active satellites. They found that it would be safer for the ESA satellite, known as Aeolus, to increase its altitude so that it could fly over the dangerous constellation.
Aeolus then fired its thrusters about half an orbit away from the potential collision. Soon after they had been calculated to potentially crash, the satellite phoned home as usual and send down the science data it had collected, assuring engineers that the collision had been avoided.
At the moment, ESA says such manoeuvres are very rare between active satellites. For the most part, satellites have to move out of the path of dead satellites or pieces left over from previous collisions.
But space agencies including ESA have repeatedly warned that megaconstellations such as those sent into space by Starlink could pose a vastly increased danger. Those constellations are projected to include thousands of satellites.
When there is such a high degree of danger, it will become impossible for engineers to manually spot potential collisions and move satellites out of their way.
Instead, ESA plans to make this process automatic, relying on artificial intelligence to move satellites out of danger.
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