It’s been a tense week for space exploration, to say the least. But after a nail biting few days that kept millions around the world on the edge of their seats, with fingers and toes tightly crossed, the ESA has announced that the Philae lander has gone to sleep.

The drama began to unfold shortly after cheers were exchanged as Philae made its momentous arrival onto comet 67P/Churyumov-Gerasimenko on Wednesday. The probe’s anchoring harpoons failed to deploy as it made contact with the surface, and because the gravity on the comet is very weak, Philae rebounded. It took two hours for the robot to finally settle, but unfortunately it ended up stuck along the edge of a crater which blocked the sun’s rays from reaching its solar panels.

Although the probe had 60 hours of primary battery, it has only been receiving 1.5 hours of sunlight during each 12-hour day which is not enough to recharge its batteries sufficiently. The ESA attempted to move the lander into a better position by activating its drills, but they only managed to lift it by 4 centimeters. Philae has now fallen into “idle mode,” with no further contact possible unless the probe gets enough juice from the Sun. Unfortunately, the ESA believes this is unlikely to happen in the coming days.

While this is undoubtedly disappointing to hear, what has been achieved so far is not to be sniffed at. Never before has a spacecraft landed on a comet, and this remarkable feat was achieved using 1980s technology. And despite all the technical problems, Philae completed its primary science mission and returned heaps of science data from its instruments, alongside some spectacular images of its surroundings.

“It has been a huge success,” said lander manager Stephen Ulamec, “the whole team is delighted.”

While Philae’s future is uncertain, the Rosetta mission is still going strong and the pair will rendezvous over the coming months as 67P/C-G creeps towards the Sun. The data gathered by the orbiter will allow scientists to observe both short- and long-term changes that take place on the comet, which will hopefully provide us with a unique insight into the history of our Solar System.

[Via ESA and BBC News]