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Physical Chemistry

Comet Lander Philae Wakes Up

After seven months of silence, the probe again begins communicating with scientific team on Earth

by Elizabeth K. Wilson
June 15, 2015

Credit: ESA/Rosetta/NavCam—CC BY-SA IGO 3.0
A close-up view of the comet 67P, taken from the Rosetta spacecraft.
Credit: ESA/Rosetta/NavCam—CC BY-SA IGO 3.0
A close-up view of the comet 67P, taken from the Rosetta spacecraft.

It’s been seven silent months, but the European Space Agency’s (ESA’s) little comet lander Philae has emerged from its unanticipated slumber, and once again contacted scientists on Earth.

The ESA’s Rosetta spacecraft, which is orbiting the comet 67P/Churyumov-Gerasimenko dispatched the dishwasher-sized Philae to the comet’s surface back in November 2014.

Philae’s landing was bumpy, however, and the craft bounced into a shadowed crater. Without sunlight to power its batteries, the lander was active for only 60 hours. The comet now is traveling nearer to the sun, so scientists had hoped Philae’s solar cells might charge up. The team switched on listening capabilities on March 12.

On Sunday, June 14, scientists at the European Space Operations Centre in Darmstadt, Germany finally received what they’d waited for: an 85-second-long data stream from Philae.

ESA issued a statement about Philae’s revival, explaining that the lander is doing well and has 24 W available in its batteries. “The lander is ready for operations,” Philae Project Manager Stephan Ulamec said in the statement.

ESA even had the lander issue its first tweet since going inactive:

Since then, scientists and lay fans around the world have sent Philae an avalanche of affectionate, congratulatory messages on Twitter.

Monica Grady, a Rosetta mission team member and planetary sciences professor at the Open University, in England, tweeted that she hugged her taxi driver when she heard the news:

The craft’s awakening should allow scientists to finally pinpoint its location on the comet’s surface. Before it went silent, Philae sent back tantalizing images of dark, high walls, but the information still wasn’t definitive enough.


Philae has apparently been collecting data for the past few days, even though it hadn’t yet been able to communicate with Earth, according to the Rosetta mission team. The team is now awaiting further data streams from Philae.

Now that Philae has been reanimated, the Rosetta team hopes the lander will drill into the comet’s surface and analyze its chemical composition.



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William Winter (June 17, 2015 7:22 PM)
Alas, C&E News shuld be technically correct, and this article is not. "the lander is doing well and has 24 W available in its batteries". The Watt or W is a unit of power not a unit of energy, so the statement has no meaning.
Elizabeth Wilson (June 22, 2015 10:48 PM)
Thanks for spotting this. We've corrected it.

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