It began with a bumpy landing and ended with a touching tweet. “I’m feeling a bit tired, did you get all my data? I might take a nap …” tweeted @Philae2014.
It was early Saturday morning, and after 57 hours performing science experiments on the surface of comet 67P/Churyumov-Gerasimenko the audacious Philae mission was coming to an end. Not enough light was hitting its solar panels and the spacecraft was preparing to hibernate but, in true Hollywood style, Philae heroically managed to send back all of its data just before the curtain fell.
Contact was lost at 00:36 GMT, a few minutes before the scheduled end of the communications window.
Within the last blocks of data that Philae returned were readings from an instrument called Cosac. They could reveal the molecular ingredients that became life on Earth, since comets are remnants from the formation of the planets 4.6 billion years ago. Their icy bodies preserve the primordial organic molecules that were incorporated into the Earth and led to the origin of life.
“The data collected by Philae and Rosetta is set to make this mission a game-changer in cometary science,” said Matt Taylor, ESA’s Rosetta project scientist.
Although now in deep hibernation, there is still a chance that Philae could revive. The comet is currently beyond Mars, but in August 2015 it will be close to Earth’s orbit and the sunlight will be much stronger.
“We still hope that at a later stage of the mission, perhaps when we are nearer to the Sun, we might have enough solar illumination to wake up the lander and re-establish communication,” said Stephan Ulamec, Philae lander manager at the DLR German Aerospace Centre.
In the meantime, the science teams are beginning to analyse the data sent back by the pioneering spacecraft. The first results are expected to be presented at the American Geophysical Union conference in San Francisco next month. The Rosetta orbiter mission will continue for another 20 months, studying the comet and listening for Philae to wake up.
It was a week of high anxiety and exhilaration for the scientists involved. Philae touched down on Wednesday afternoon after a seven-hour descent from the Rosetta orbiter. Earlier in the day, engineers had realised that the thruster system on Philae was not responding.
