About seven months after making a bumpier-than-expected landing on a comet hurtling through deep space, the European Space Agency's (ESA) Philae lander successfully reestablished contact with scientists on Earth late Saturday, marking a milestone in an already unprecedented mission.
The ESA announced the news on Sunday morning eastern time, but said that the data was first received in a burst that lasted about 85 seconds, from the comet lander on Saturday. The data was relayed by the Rosetta spacecraft, which is orbiting the comet. The Rosetta Mission is the first ever mission to successfully land a spacecraft on a comet.
More than 300 "data packets" have already been analyzed by the teams at the Lander Control Center at the German Aerospace Center.
"Philae is doing very well: It has an operating temperature of minus-35 degrees Celsius and has 24 Watts available," said Philae project manager Dr. Stephan Ulamec, of the German Aerospace Center, in a statement.
Incredible news! My lander Philae is awake! http://t.co/VtzAQHx4zT pic.twitter.com/SZqnsnNpUZ— ESA Rosetta Mission (@ESA_Rosetta) June 14, 2015
"The lander is ready for operations," Ulamec said.
Late last week, the ESA had stated they were working to narrow down the area where Philae had landed on Comet 67P, saying it was likely in a shadier spot than planned for in mid-November, and therefore was having trouble charging its batteries via solar panels.
The lander communicated with the Rosetta spacecraft, which has been orbiting the comet as a space communications relay device and imager, for just 60 hours after landing before going dark on Nov. 15, 2014.
On June 11, ESA scientists said the little spacecraft, which is about the size of a refrigerator with 10 key instruments aboard,may have traveled as far as a kilometer, about 0.6 miles, from where it touched down on the comet initially.
Hello @Philae2014! You’ve had a long sleep, about 7 months!— ESA Rosetta Mission (@ESA_Rosetta) June 14, 2015
Wow @ESA_Rosetta! That’s a long time… time for me to get back to work! #Lifeonacomet— Philae Lander (@Philae2014) June 14, 2015
.@Philae2014 Need to check you’re fit, healthy and warm enough first @philae2014! Take it easy for now :)— ESA Rosetta Mission (@ESA_Rosetta) June 14, 2015
In an interesting twist that scientists are looking into, the data that arrived on Saturday indicates that Philae was also awake earlier in the mission as well.
"We have also received historical data -- so far, however, the lander had not been able to contact us earlier," Ulamec said.
There are still more than 8,000 data packets in Philae’s mass memory which will give the German Aerospace Center scientists information on what happened to the lander in the past few days on Comet 67P, also known as the Comet Churyumov-Gerasimenko.
Searching for Philae's exact location
The ESA still doesn't know exactly where on the comet the lander is residing.
Scientists have been using radio signals beamed back and forth from Philae to Rosetta during the 60 hours the lander was functioning after landing to narrow down the area where the lander probably ended up. But scientists need to figure out where Philae is within that area — a 16 meter by 160 meter, or about a 52 foot by 524 foot, ellipse on the comet.
As the comet has been speeding toward the sun, the amount of heat and light reaching the comet has been increasing, raising the odds that Philae would wake from its hibernation.