UPDATED Nov. 14, 2014, 5 p.m. PT
After a last-ditch attempt at a second wind, the Philae comet-lander has gone into standby mode.
But before depleting its batteries and losing signal, Philae was able to send data it had collected to the European Space Agency, which now plans to analyze the findings. The space probe that joined Philae on its mission will continue to keep tabs on the comet, 67P/ Churyumov–Gerasimenko, according to tweets sent by accounts run by the space agency.
.@Philae2014 S'ok Philae, I’ve got it from here for now. Rest well... #lifeonacomet #67P #CometLanding— ESA Rosetta Mission (@ESA_Rosetta) November 15, 2014
Thank you, @ESA_Rosetta! I did it! I became the first spacecraft to land on a comet & study it! But it’s not over yet… #CometLanding— Philae Lander (@Philae2014) November 15, 2014
The space agency lost signal at 4:36 p.m. PT Friday, or 12:36 a.m. UTC Saturday, according to a European Space Agency blog post. The loss of signal occurred not long before a "scheduled communication loss that would have happened anyway as Rosetta orbited below the horizon," the blog post states.
The Rosetta space probe "will listen for a signal" to reconnect with the lander. Officials have pegged 2 a.m. PT Saturday, or 10 a.m. UTC, as the next time the orbiter and Philae may be able to communicate.
Philae's attempt to gain more power was praised by the science community, and the European Space Agency. Many shared encouraging notes about Philae, who some have dubbed the "little lander that could."
.@Philae2014 You've done a great job Philae, something no spacecraft has ever done before. #CometLanding— ESA Rosetta Mission (@ESA_Rosetta) November 15, 2014
Loss of signal from @Philae2014. But its data will be with us… always. #CometLanding pic.twitter.com/pXyIuN7Lj5— Jason Major (@JPMajor) November 15, 2014
So proud of you RT @Philae2014: .@ESA_Rosetta I'm feeling a bit tired, did you get all my data? I might take a nap… #CometLanding— ESA (@esa) November 15, 2014
“@Philae2014: @ESA_Rosetta I'm feeling a bit tired, did you get all my data? I might take a nap… #CometLanding” Sweet dreams. Love, Earth.— Bobak Ferdowsi (@tweetsoutloud) November 15, 2014
Philae lost steam after making a move to get more sunlight to its solar panels as battery life drained on the refrigerator-sized robot, which is hurtling through space on a comet somewhere between Jupiter and Mars.
On Friday night, Philae was losing power, and fast.
So much hard work.. getting tired... my battery voltage is approaching the limit soon now pic.twitter.com/GHl4B8NPzm— Philae Lander (@Philae2014) November 14, 2014
According to the European Space Agency, Philae's main body was successfully rotated, exposing one of the larger solar panels to the meager sunlight that is falling on one of the smaller ones. But the solar generators were not receiving enough sunlight for a recharge in the lander's current location.
"The rotation of the lander's body could result in more power if one of the larger solar panels can catch the illumination that is falling on the smaller," says ESA's Mark McCaughrean, senior science advisor. "All things being equal, the same amount of sunlight falling on a larger panel should result in more power being generated."
I just started lifting myself up a little and will now rotate to try and optimize the solar power! — Philae Lander (@Philae2014) November 14, 2014
Also my rotation was successful (35 degrees). Looks like a whole new comet from this angle:)
— Philae Lander (@Philae2014) November 14, 2014
But the successful rotation did not put the mission in the clear.
The space agency noted that future contact could be possible if the lighting conditions change as the comet orbits closer to the Sun, enabling solar power to flow.
I'm running out of energy quite fast now... look at the scientists watching how my energy status is going down! pic.twitter.com/nHFpRPGNzD— Philae Lander (@Philae2014) November 14, 2014
The lander, which came to rest on the comet on Wednesday after a 10-year long mission, had been unable to utilize its solar panels properly after a bouncy landing left it in the shadow of a cliff.
The European Space Agency made history by landing Philae on the comet, but the mission has not been straightforward. The Rosetta spacecraft dropped the lander onto comet 67P/Churyumov-Gerasimenko, speeding between Jupiter and Mars at nearly 40,000 mph. But three bounces off the surface of the comet left Philae in a location that was less than ideal. Despite all of the issues, the lander conducted more than 56 hours of experiments by Friday evening.
"While the search for the final landing site is still on-going, the lander is racing against the clock to meet as many of the core science goals as possible before the primary battery is exhausted," the ESA posted on its Rosetta blog. "Under the low illumination conditions at Philae’s location, it is unlikely that the secondary batteries will charge up enough to enable extended surface operations."
Thanks to all of you who have shared this night with us, good night— ESA (@esa) November 15, 2014
Additional reporting by Brittany Levine and Kate Sommers-Dawes