The European Space Agency’s Philae Minilab Lander, which had been in enforced hibernation for seven months after landing in a shadowy crevice on Comet 67P/Churyumov-Gerasimenko, has woken up. Signals from the craft were received at ESA’s European Space Operations Centre in Darmstadt at 2128 GMT on 13 June 2015 after being relayed by the Rosetta orbiter.
More than 300 data packets have been analysed by the teams at the Lander Control Center at the German Aerospace Center (DLR).
“Philae is doing very well: It has an operating temperature of -35ºC and has 24 Watts available,” explained DLR Philae Project Manager Dr. Stephan Ulamec. “The lander is ready for operations.”
For 85 seconds Philae had telemetry contact – its first since going into hibernation in November. It also became clear that Philae has data from when it was previously awake with a further 8000 data packets in Philae’s mass memory waiting to be delivered.
Rosetta’s orbit around the comet is now being lowered to help relay communications, with the caveat that if dust and outgassing from the comet interferes with its operation (as it did before) it may be raised again.
Philae shut down on 15 November 2014 at 0015 GMT after being in operation on the comet for about 60 hours.
The craft originally ran out of battery power as there was not enough illumination for the solar arrays to recharge it at the landing site. There were hopes that when the sun angle improved, as the comet approached its perihelion, the increased illumination would allow the lander to wake up and recontact earth via its Rosetta relay spacecraft. The relay craft had been listening out for Philae since 12 March 2015 when its communication unit was turned on, and this has now happened.
According to ESA scientists, landing in a crevice was fortunate for the spacecraft as it protected Philae from overheating during its hibernation. Such has been the success of the Rosetta-Philae mission that ESA has been extended by nine months to September 2016. This will allow scientists to make observations of the comet as it moves away from the sun to complement those taken on its orbital ingress. It is also planned to attempt to skid land the main Rosetta spacecraft on the comet itself – even though Rosetta was never designed for such a landing.
