This is the first image ESA is releasing from the comet. It shows Philae settled at the base of a rocky comet cliff. ESA
We landed a motherfucking spacecraft on a comet.
And then it bounced off. Twice. And the scientists and watching world held a communal breath.
We can all exhale, as not only is Philae back on the surface, somewhere, it is sending pictures to ESA. Those pictures show that one of Philae’s three feet is not currently touching the comet’s “ground.” It is suspended in the vacuum of space. In a stunning, currently unprocessed image, you can just make out the suspended lander foot over-exposed in the shadow of a massive cliff. This shadow means Philae’s solar batteries are not charging at the expected rate, but at a press conference this morning an emotional and sleep-deprived European Space Agency emphasized that Philae is stable. For now.
Philae should have sent harpoons into the surface to anchor itself to the comet as it hurtles through space. As was clear pretty soon after contact yesterday, that mechanism failed.
“After our first touchdown signal we could tell that something was not normal because Philae was still moving. The lander kept rotating,” said Stefano Mottola from the Lander Control Centre in Cologne, Germany. This could have been very bad. The team feared Philae would not make contact with the comet again. But then, after nearly two hours, “we saw that the rotation stopped. The rotation could only stop by touching the comet again.”
But it’s reverberations were not over yet. The surface of the comet “is not a powder, it’s a rock,” said lead scientist Jon Pierre Bilbring. “This material is like a trampoline. You go there and it ejects you immediately afterwards.” After its first 2-hour bounce, during which time it traveled nearly a kilometer, Philae took another short hop, going 3 centimeters a minute for 7 minutes. And that’s when it settled down at the base of a large wall, relying on gravity to hold it in place.
Though the ESA could now fire the harpoons to ensure Philae latched, the team is wary of doing so, as it could thrust the spacecraft off the comet. “You can imagine the gentle manuevre that we must do now to maintain the location of the lander. We will do that in the next hours and possibly days. We might stilll be able to modify the orientation of the lander,” said Jon-Pierre Bibring of CIVA.
Bilbring took exception to the characterization of the landing position as “awkward” and unideal, saying, “it is gorgeous where we are.”
The team is working hard to figure out how to fix the lander’s orientation, however. But first they need to understand exactly where they have landed. “We would not dare operate the landing gear without first knowing where we are,” said Stephan Ulamec, the principal investiogator in charge of the landing mechanism. “If the material is too soft or too hard it would put momentum on the lander and push us away from the surface. So these activations will not happen in the next hours for sure.”
The very good news is that though they can’t be precisely sure where Philae is, ESA is familiar with its unexpected landing spot. Before deciding on where to aim for the landing, the team investigated many landing spots and carefully weighed the merits of each. They had aimed for landing site J, but the new spot in the shadow of the cliff is very close to landing zone B.
“I was joking that we jumped from one ‘preselected landing site to another,'” joked Ulamec.
Incredibly, the first touchdown was nearly bullseye perfect. An image from 50 kilometers pre-landing shows a flat and ideal spot at the center of the target, site J. “We would have wished it stayed there, but we know it didn’t,” said Bilbring. “We will find the lander. We are waiting like hell to show you where it sits.”
At one point in the morning’s conference, Flight Director Andrea Accomazzo gave an emotional shout out to Stefan Ulamec, tears welling in his eyes as he expressed his admiration for how he handled the complicated landing and mission.
Because of the shadow, Philae is not getting as much power from the sun as the team had planned for. The batteries will last through tomorrow for sure, but the day after will be the critical time for drilling down into the surface and gathering data.
However, even if the batteries cannot last past 60 hours from now, Philae could potentially be awoken from a hibernation in a few months when (and if) more solar energy hits its position. “If even in months the solar situation will change completely, we can still wake it up,” said Ulamec.
“Tomorrow is another day for Philae. 2015 is another year for Rosetta,” Ulamec cheered. Rosetta will continue orbiting the comet for another 20 months, no matter how long Philae remains active.
Editors’ Note: We will update this story as images and data come in throughout the day.
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