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Philae sleeps, but Rosetta's not done yet

Its battery dead, the European lander is lost in a crater somewhere on a huge comet. But the orbiter that brought it there still has plenty of science left to do.

Eric Mack Contributing Editor
Eric Mack has been a CNET contributor since 2011. Eric and his family live 100% energy and water independent on his off-grid compound in the New Mexico desert. Eric uses his passion for writing about energy, renewables, science and climate to bring educational content to life on topics around the solar panel and deregulated energy industries. Eric helps consumers by demystifying solar, battery, renewable energy, energy choice concepts, and also reviews solar installers. Previously, Eric covered space, science, climate change and all things futuristic. His encrypted email for tips is ericcmack@protonmail.com.
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Eric Mack
2 min read

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Philae sleeps, but Rosetta remains. ESA

As of Saturday morning, the Philae lander is in a digital coma somewhere on the surface of comet 67P/Churyumov-Gerasimenko. But even if the history-making little robot never wakes again, the Rosetta mission and the orbiter of the same name still have a long journey ahead of them.

The plan was for Philae to land at a targeted site on the comet, firing harpoons into the surface of the icy rock to keep itself locked in place for a long trip around the sun. The strong grip was particularly important since a comet this size has only a tiny fraction of the gravity of a place like Earth, leaving little Philae at risk of floating off into space.

But when showtime came, there were problems with Philae's downward thrusters and with firing the harpoons. The European Space Agency reports that the lander bounced off the surface of the comet twice and eventually landed somewhere else without much access to the sunlight its solar panels need to keep it functioning.

Friday evening, Philae used its remaining energy to upload all its data before going into hibernation mode. There was a time slot early this morning during which, the ESA had reported, communication with the lander was possible, but that time has now come and gone.

Still, Rosetta remains.

Even if Philae stays lost in a comet crater for the next year, the orbiter that traveled almost half a billion miles to get to this point will continue to orbit the comet and its lost lander.

Right now, Rosetta has been pulling out to a 30 kilometer orbit of the comet. It will come closer again early next month to get more details on the comet -- some of its flybys will be as close as 8 kilometers to the comet. There's a whole lot of potential science and data about comets, planets and our solar system packed in that process, building up to the trio's closest encounter with the sun, next August.

Before that point there may also be better opportunities to rouse Philae.

"We still hope that at a later stage of the mission, perhaps when we are nearer to the sun, that we might have enough solar illumination to wake up the lander and re-establish communication, " Stephan Ulamec, lander manager, said in an official statement.

For now though, Philae sleeps as Rosetta makes the rounds and works on a particularly important surveillance mission to analyze its new neighborhood and look for its lost lander. Take a look at the video below to see how the orbiter is performing the task at hand.

Rosetta's long journey from here to a comet (pictures)

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Philae lands on a comet (pictures)

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