Now, in photographs taken by Rosetta’s OSIRIS camera as the spacecraft zoomed within 2.7 kilometers (1.6 miles) of the comet’s surface on Sept. 2, the guesswork of Philae’s fate can be put to rest. The lander really did end up on its side, with two of its three legs awkwardly poking upwards. It seems to be jammed in a dark crack, proving why it was so hard to maintain contact with the robot after landing.
The activity reaches its peak intensity around perihelion and in the weeks that follow – and is clearly visible in the spectacular images returned by the spacecraft in the last months. One image taken by Rosetta’s navigation camera was acquired at 01:04 GMT, just an hour before the moment of perihelion, from a distance of around 327 km.
If this commanding works, Philae could re-start its scientific measurements and, if a link is established with Rosetta, it would be able to send its data back to Earth, via the orbiter.
For 85 seconds Philae “spoke” with its team on ground, via Rosetta, in the first contact since going into hibernation in November.
Now the scientists are waiting for the next contact. There are still more than 8000 data packets in Philae’s mass memory which will give the DLR team information on what happened to the lander in the past few days on Comet 67P/Churyumov-Gerasimenko.
Short recap: Philae is the craft that landed on the comet and Rosetta is circling about being the direct link to the lander kind of like how Apollo missions operated for manned moon landings. Both Philae and Rosetta travelled to the comet together and then 211 days ago Rosetta launched Philae onto the surface of the comet where it bounced funny landing next to a cliff that blocked sunlight to its solar panels. Apparently it now has gathered enough juice to be somewhat operational. This is quite an amazing feat involving every STEM discipline from mathematics to rocket science.
I wonder if they’ll reconsider shutting down this program as mentioned here.
xkcd has been all over this story from the landing; From: http://xkcd.com/1446/
The mission is currently set to end in December 2015, after which Rosetta could simply be switched off as it continues to orbit the comet, and the mission team disperse to work on new projects. But for several months now a plan has been quietly hatched to see the craft go out with a bang by being brought down to a collision with 67P.
It would see the spacecraft brought gradually closer to the comet in a slowly spiralling orbit that would allow its cameras and instruments to gain ever more detailed views and measurements of the twin-lobed icy body. Then eventually—probably in September 2016—it would collide with the comet, bringing the mission to an end.
The Rosetta spacecraft detected the molecular nitrogen using the probe’s ROSINA instrument (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) between Oct. 17 and 23, 2014. At the time, Rosetta was orbiting just 6.2 miles (10 kilometers) from Comet 67P’s center.
The little probe delivered everything expected from it, just as its failing battery dropped it into standby mode.
Philae is pressed up against a cliff. Deep shadows mean it cannot now get enough light on to its solar panels to recharge its systems.
“Philae could come back later as we move closer to the sun, and we get more light onto the solar panels up against the cliff we’re at here in the shadows.”
The three-legged lander had to be released at exactly the right time and speed because it could not be controlled on its descent. On its way down, Philae gathered data and images, which were relayed back to Earth.
Engineers designed the lander not knowing what type of terrain they would find on the comet’s surface. Rosetta has been taking pictures of the comet and collecting samples from its atmosphere as it approaches the sun, showing it is not as smooth as initially hoped, making landing more tricky.
Philae’s legs are designed to damp out the forces of a hard landing to reduce the lander’s chance of bouncing. When Philae touches down, it will fire two harpoons to attach it firmly to the comet’s surface. A thruster on top of the lander fires at the same time as the harpoons, keeping the lander on the ground. Ice screws also deploy from the three lander feet.
Philae may have landed not once but twice – that’s the final message from Esa this evening.
According to Stephan Ulamec, Philae Lander Manager, DLR, the lander team believe that Philae may have bounced from the surface and settled again in a slightly different place.
Two robust landing scenarios have been identified, one for the primary site and one for the backup. Both anticipate separation and landing on 12 November.
For the primary landing scenario, targeting Site J, Rosetta will release Philae at 08:35 GMT/09:35 CET at a distance of 22.5 km from the centre of the comet, landing about seven hours later. The one-way signal travel time between Rosetta and Earth on 12 November is 28 minutes 20 seconds, meaning that confirmation of the landing will arrive at Earth ground stations at around 16:00 GMT/17:00 CET.