Landing on a comet ... and staying there

[klr]

The first bit is simple ... the second, maybe not so.

A European robot probe has made the first, historic landing on a comet, but its status remains uncertain after harpoons failed to anchor it to the surface.

Officials said the craft may have lifted off the comet after touchdown before returning to the surface.

Lander project manager Stephan Ulamec said: "Maybe we didn't just land once, we landed twice."

Further analysis is needed to fully understand the situation.

However, Dr Ulamec told the BBC that at last radio contact with the probe that he believed it to be in a stable configuration.

"This is the indication right now," he explained. "We really have to wait until tomorrow morning and then we will know a lot more."

The "first" landing on Comet 67P/Churyumov-Gerasimenko was confirmed at about 1605 GMT.

There were cheers and hugs at the European Space Agency's mission control in Darmstadt, Germany, after the signal came through.

...

http://www.bbc.com/news/science-environment-30026398

[Clinton Huxley]

It could have two firsts - first to land on a comet and first to take off from one....

[klr]

It could have two firsts - first to land on a comet and first to take off from one....

I hope the ESA has some good spin doctors on hand ...

[klr]

Chris Lintott reporting now for BBC Newsnight, on location*.

*That's in mission control in Darmstadt, not on P67.

[cronus]

Landed then....took off and landed again, on its side. Not hard to imagine given the micro-gravity.

[JimC]

Bouncy-bouncy...

[Clinton Huxley]

Tense times, waiting for the orbiter to be back in position to receive radio signals. Still an amazing feat to get it there at all.

[pErvinalia]

Apparently they are going to try and manually fire the harpoons.

[Clinton Huxley]

Apparently they are going to try and manually fire the harpoons.

Risky. Will either anchor it in place, or blow it off the comet. Still, what else to do?

[mistermack]

I think it's bounced twice, and landed three times.

It's not on it's side, they know that because they have a picture of one of it's feet on the surface.
But it might be at an angle, and it seems to be in a dark spot, so that after the main battery expires, it might not have enough light to charge the rechargeable one.

They have said that all of the main objectives can be achieved on the primary battery, and it's a bonus if the rechargeable one works, and that will be for secondary science.

I would imagine that they'll do everything that they can, in it's present position, and then, if the light is too weak for charging, they will then try the harpoon again, hoping that it might bounce it to a brighter location.

If they had anticipated this, they could have installed a big mirror on the orbiter, that could direct light onto the lander in the event that it landed in the shade.

[rachelbean]

It was pretty cool to watch the last minutes before it happened, and the joy that was felt once it made contact. It has to be heart-breaking to be dealing with what they are now, but it was still an amazing feat, and hopefully there is still a lot that can be salvaged from the mission (I mean the orbiter itself has a lot to do).

[Svartalf]

They were all "getting Rosetta to orbit the comet was the real exploit, Philae would just be icing on the cake", but now they are working triple time to try and get it to right itself and get more sunlight so it can complete its work...

[klr]

It took two hours to come back down after the first bounce. Micro-gravity indeed.

[klr]

Someone should make one of those online video games to simulate the landing process. If they've not already done so.

Actually, if done well, it would be very educational. Let people vary the size (and therefore mass/gravity) of the comet, its shape, speed, etc.