Philae May Have Grazed Crater Rim

An anonymous reader writes: The European Space Agency is gradually sorting through the data collected during the brief window Philae was alive and transmitting on the surface of a comet. Analysis of that data has provided another interesting clue about what happened to the probe as it bounced across the comet's surface. According to results from the on-board magnetometer, immediately after the first touchdown, the lander's spin rate increased somewhat. It continued to spin for about 36 minutes until another event dramatically changed its spin rate. This suggests it collided with something, because there was no corresponding vertical deceleration to indicate it had landed once more. Scientists think Philae likely grazed the rim of a crater with one of its landing legs. 65 minutes later, it landed again, and bounced to its final resting place just a few minutes later. The ESA's article has some interesting graphs showing how the data changed as the lander progressed through these different events.

Comments

Re:Almost made it ...

[gstoddart]

The mission did not succeed in most of its stated objectives. By definition that makes it a failure.

Well, think of it as being two distinct phases.

First, you rendezvouz with the comet. That's an extraordinary feat, and worked brilliantly. It represents several firsts, because matching speed with a comet and being in the same place it's supposed to be in 10 years? That's pretty damned hard to do.

Second you fire the lander portion at the comet and hope it sticks. And it has to stick to an object you aren't 100% sure of its shape, rate of spin, and composition. And it has to do it by itself because of the communication delay.

Which seems kind of like trying to tell a blind person when to cross the street based on your out-dated video view of the street, and no idea what the future traffic is going to be.

The part that failed was the "OK, you're mostly kinda pointing across the busy highway ... now start running when you get this and let us know when you get to the other side".

And in an interview I heard with one of the project members before the final landing ... they knew damned well that was kind of a high risk thing, and was being done completely blind.

So, the huge task of making rendezvous was pretty much textbook.

The blindfolded-on-a-moving-train "Annie Oakley" sharp shooting bit? Surprisingly, quite difficult.