The European Space Agency's Gaia mission is an ambitious project that aims to provide a complete map of the dizzying number of stars in our home galaxy.
New research suggests it might have also picked up a few extragalactic foreign invaders.
Since launching in 2013, the mission has provided some incredible data on 1.7 billion stars.
With so much data to work through, astronomers have their work cut out for them -- and on Tuesday, the ESA announced that astronomers found stars not being flung away from the Milky Way, but further into it.
Stars speed around the Milky Way at hundreds of kilometres per second, but the fastest of them can travel upward of 1,000km/s and are known as hyper-velocity stars.
The consensus has been that these fast moving stars start their lives in the middle of the Milky Way, before being flung further and further out.