The European robot probe Philae has made the first historic landing on a comet, but its status is uncertain after harpoons failed to anchor it to the surface.
Officials said the craft may have lifted off the comet after touchdown before returning to the surface.
Lander project manager Stephan Ulamec said: "Maybe we didn't just land once, we landed twice."
The European Space Agency's director general described the landing as "a big step for human civilization".
The "first" landing on Comet 67P/Churyumov-Gerasimenko was confirmed at about 16:05 GMT.
There were cheers and hugs at the European Space Agency (Esa) mission control in Darmstadt, Germany, after the signal came through.
Early data started to come back from instruments, and one team could see that the lander had sunk about 4cm into the surface, suggesting a relatively soft top layer.
Photo: the comet as Philae descends
|