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curiousuburb
Antimatter Man
 
Join Date: May 2004
Location: that interweb thing
 
2014-11-13, 03:52

Not so smooth landing after all... in fact, three landings!

First time apparently sunk down 4 centimetres (implying soft surface, not something hard the ice screws could grab), then it bounced up to 450 metres (auto-sequence landing harpoons didn't fire and cold gas thruster on top designed to push it back down was borked ).

That sounds like 0 for 3 on the redundant auto-attachment systems. (Although to be fair, the ice screws may have functioned correctly, just failed to grip a softer than expected surface.)

The CIVA panoramic cameras also seemed wonky, as they returned black frames or gibberish rather than surface images, despite returning images on the way down to the surface. Rather than just attempt some *ahem* percussive maintenance on the boxes at mission control to see if that fixes things, they can apparently get Philae to resend that data in parallel while it is doing other science.

Fortunately, physics still works, and (feeble or not) gravity pulled Philae back down slowly... and it bounced again about 5 metres... then touched at least twice more before Rosetta orbited around the comet and lost signal for the night.

Happily, they reestablished contact and they're waiting for news today on final orientation and position. Apparently all science instruments are working and getting data.
This series of images indicates the location of the first touchdown of the Philae lander on comet Churyumov-Gerasimenko. A NavCam image, on the left, provides global context. The next two images, from the OSIRIS science camera, give regional context. The final two images, from the ROLIS descent camera, localize the landing site. However, indications are that the spacecraft bounced, so the final landing site is likely in a different location.
ESA / Rosetta / Navcam / Philae / ROLIS / MPS for OSIRIS Team MPS / UPD / LAM / IAA / SSO / INTA / UPM / DASP / IDA Click for huge

If it's upright and stable on the surface they can try and manually fire the harpoons.

Otherwise they may just crack on with primary science as best they can... and hope the sampling drill helps pull them down rather than push them away, and that no outgassing or other events interrupt what was planned to be a whirlwind 2.5 day experiment sequence.

If they accomplish the full slate of activities on the priority list, everything after that is a bonus. And even if Philae were to get blasted off the surface, they ought to be able to characterize that event with multiple instruments, "sniffing" the jets and getting groovy science then, too.

**UPDATE: 09:45 GMT ** Project Scientist Matt Taylor on BBC just confirmed Philae is stable and sending data (2 more hours this pass before LOS as Rosetta drops below the horizon)

More details from Emily Lakdawalla's blog at Planetary Society.

Next major briefing will stream online at 13:00 GMT

All those who believe in telekinesis, raise my hand.

Last edited by curiousuburb : 2014-11-13 at 04:49. Reason: BBC interview with Project Scientist adds info
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