European robot probe Philae has made the first, historic landing on a comet, after descending from its mothership.
The lander touched down on Comet 67P/Churyumov-Gerasimenko at about 1605 GMT.
There were cheers and hugs at the control room in Darmstadt, Germany, after the signal was confirmed.
It was designed to shine a light on some of the mysteries of these icy relics from the formation of the Solar System.
"THIS IS A BIG STEP FOR HUMAN CIVILISATION" said Jean-Jacques Dordain, the director-general of the European Space Agency (Esa).