Sun like it hot: Philae comet probe wakes up, phones home again

ESA shifting Rosetta 'craft for better comms with lander

The Philae probe on Comet 67P/Churyumov-Gerasimenko has been in contact again, the European Space Agency has confirmed – and the lander is getting more than enough sunshine on its solar panels to power itself continuously.

Battery warm & solar panels getting energy. Anxious to explore, comet day & night! More about #lifeonacomet from LCC http://t.co/nokzuuKEno

— Philae Lander (@Philae2014) June 19, 2015

Philae has been out of contact for months after a botched landing, but on Monday contact was established for the first time. Another data burst came through on Wednesday, mainly confirming that the probe had survived, but it is now reporting that it is getting enough sunlight for continuous operations.

The lander managed 19 minutes of data streaming up to the Rosetta probe orbiting the comet, which then forwarded the data back to a receiving station in Germany. Friday's data burst consisted of just 185 data packets, but it confirmed that the Philae probe is back in business and ready for science.

"Among other things, we have received updated status information," said Michael Maibaum, a systems engineer at the DLR Lander Control Center (LCC) in Cologne.

"At present, the lander is operating at a temperature of zero degrees Celsius, which means that the battery is now warm enough to store energy. This means that Philae will also be able to work during the comet's night, regardless of solar illumination."

.@ESA_Rosetta engineer Roberto Porta watches telemetry coming down from @Philae2014 at #ESOC #wakeupphilae pic.twitter.com/DjatdhF4mY

— ESA Operations (@esaoperations) June 19, 2015

Four of the lander's solar panels are now getting a good amount of sunlight as the comet falls towards the Sun and the probe is recording data, although the Earth-bound controllers haven't been able to communicate with it long enough to operate its ten instruments as yet.

To rectify that, the Rosetta probe is going to fire up its thrusters and get closer to the comet's surface so that a firm data link can be achieved. The probe will swoop down to orbit around 180km (112 miles) from the comet's surface to establish control of Philae, which has been in hibernation mode since its problematic landing.

When the Philae probe fell towards the comet, it bounced across the surface, ending up at an angle overshadowed by a cliff. At the time, this was viewed as a serious problem, but the landing may prove to be a blessing in disguise.

Had the probe landed in direct sunlight, as planned, the sun's rays would have cooked it by now. Because the lander is partially in the shade, it's still well within operating temperatures and should be able to send back data as the comet heats up, offering clues as to how the heating process affects its chemistry.

It's not known how long the lander will be able to transmit data, but neither it nor Rosetta itself are going anywhere. The two probes will spend the rest of their lives accompanying the comet as it journeys through the cosmos. ®