The Philae lander is awake on its comet. Now what?

Philae wakes up after a long hibernation on Comet 67P.
Philae wakes up after a long hibernation on Comet 67P.
Image: ESA

The first space probe to ever make a soft landing on a comet flying through deep space just woke up after seven months of silence.

European Space Agency mission controllers working with the Philae lander heard from the washing machine-sized probe for about 85 seconds on Saturday, a burst of communication indicating that the little spacecraft is alive and apparently able to beam back information from the surface of Comet 67P.

So, what's next?

Scientists currently have a backlog of data they need to sift through. According to the ESA, they've analyzed about 300 packets of data sent home from Philae through the Rosetta spacecraft orbiting Comet 67P; but there are more than 8,000 packets that still need to be retrieved from its memory to get a clearer picture of what has been happening to Philae in the last few days.

The spacecraft apparently woke up earlier in the mission, but wasn't able to immediately phone home.

"We have also received historical data — so far, however, the lander had not been able to contact us earlier," Philae project manager Stephan Ulamec said in a statement.

However, that wakeup without communications was somewhat expected. The comet was probably warm enough for Philae to start waking up in March, but the ESA knew it would take until May or June for the craft to have enough power to use its transmitter, allowing it to communicate with Earth, mission controllers said in a January update.

Philae's solar panels are likely receiving more sunlight now, and it is apparently getting ready for more science. "The lander is ready for operations," Ulamec said.

Philae was awake on the comet's surface for about 60 hours after it made its unexpectedly bumpy landing in November 2014. But instead of holding fast to the surface of the comet where it first touched down, the spacecraft bounced twice, putting it in a seemingly shady area of the comet where its solar panels didn't get enough sunlight.

Mission managers deployed Philae's drill to get some much-needed samples of the cosmic body's subsurface in the short amount of time it was awake, but those efforts seemed to be unsuccessful. Although the probe managed to get a taste of the comet's atmosphere, it went dark.

The comet that Philae woke up to on Sunday is probably very different than it was when the lander went to sleep. Comet 67P is now only two months away from its closest approach with the sun in August, which means it is definitely heating up. One major objective of Philae and Rosetta's mission is to gather unprecedented data on how the comet changes throughout its roughly 6.5-year journey around the star — and Philae's wakeup could allow scientists to do just that.

The probe might use its drill again to get a good sample of Comet 67P, which it can analyze using its 10 onboard instruments. Comets are considered leftovers from the dawn of the solar system, so learning more about the composition of these icy and dusty bodies could be a window into the beginnings of Earth and the rest of our cosmic neighborhood.

Scientists are also hoping that Philae will be able to take more photos of the comet's surface.

If all goes well, Philae should be able to help Rosetta more fully chronicle the changes that Comet 67P experiences, as it makes its way around the sun. The comet's body will change as it heats up even more, sprouting jets of gas from its surface. So having Philae as a sentinel on Comet 67P, observing some of those micro-changes while Rosetta gets the bigger picture from above, could help scientists in their mission to understand how comets change during their paths around our home star.

Philae's wakeup could also mean that the ESA will be able to pinpoint exactly where the lander ended up on Comet 67P's surface. Scientists have been hunting for Philae's final resting place ever since the probe touched down on the comet; but now, the craft might be able to radio Rosetta, narrowing down its location even further.

The probe's wakeup also proves that it is a robust little machine. Philae was likely exposed to extremely low temperatures during its hibernation on the comet's surface, but its circuitry appears to be working well enough to allow it to send information back home via Rosetta.

Rosetta, with Philae housed within it, launched to space in 2004 on their 4 billion mile journey to Comet 67P.