A satellite belonging to the European Space Agency has had to perform a special move for the first time to avoid a big crash with some wspace junk.
The ESA says it pulled off the "collision avoidance manoeuvre" to stop the satellite hitting what it called a "mega constellation".
The constellation is made up of loads of internet satellites called Starlink that were put into space by Elon Musk's company, SpaceX.
But the ESA is worried that moves like this might not be possible in the future as more and more satellites, making up massive constellations, arrive in space.
It says that will increase the risk of possible collisions and make things very difficult.
Aeolus, the ESA satellite involved in the near-miss, had to move higher so it could fly over the space junk.
It then sent data back to engineers here on Earth to confirm that the collision had been avoided.
At the moment, the ESA says moves like this between active satellites are very rare. If satellites do have to move, it's usually to get out of the way of other satellites that are no longer working.
With an increase in the number of satellites, scientists are worried that it will become impossible for humans monitoring from Earth to spot possible collisions and move satellites out of their way.
Instead, the ESA will bring in artificial intelligence which will constantly scan space to move satellites out of danger.