Darkness and cold mean it’s time to let go of the Philae lander

It’s hard to say goodbye, even if you knew it was coming from the start. After a project that began over a decade ago, the European Space Agency is officially ending the Philae mission on Comet 67P. The ambitious project has faced its share of difficulties, and researchers have decided that it’s time to move on from the lander, which is almost certainly out of power after months without charging its batteries. Furthermore, as the comet is now moving away from the sun, temperatures will be dropping to points where Philae’s on-board computers can’t function, even if a full battery were available.

Coping with unknown conditions

The lander had a particularly tough set of circumstances to deal with. Since it was being delivered by the Rosetta spacecraft on our first visit to Comet 67P, scientists didn’t know where they’d be able to land before they arrived. Many expected a softer surface on the comet, making the bouncing and failed tethers a bit of a surprise, albeit one that still yielded useful data. Since it landed in a shadowed location, it has managed to recharge a bit, sending back a few more readings. However the latest attempt on January 10th of this year to reposition slightly, or at least shake off some dust, had no response, and so there’s really nothing more that can be done in the increasingly chilled environment.

Data delivered

While it seems sad that this spectacular mission is drawing to a close out of our control, it was in no way a failure. The lander managed to perform 80 percent of it’s planned reporting before its initial power supply was depleted. Much was learned about the comet, including that it wasn’t composed of layered material, indicating it was formed in a gentle process of assimilation, and might still have some untouched material from the beginnings of the universe at its core.

While we’re no longer communicating with Philae, the Rosetta spacecraft is still orbiting the comet, at least until September. At that point, it will be sent to crash into the comet, taking pictures along the way. While some final photos of Philae’s location are obviously of greater interest after losing contact with the lander, the crash landing has been planned, as with many other missions in our solar system. While we’ve become a bit spoiled by seemingly immortal robots like Opportunity on Mars, exceeding their mission time by over a decade, Philae’s manager, Stephan Ulamec would remind us that “…it would be sad if we concentrated so much on what we couldn’t achieve and not on what we did.”

Source: Time running out on comet lander by Christopher Crockett, Science News