The leg screws are automatic, when the landing gear pads hit the surface the screws rotate, but without the gas thruster pushing down and the nature of the ground the ice screws did not hold. I doubt on the second and third landing the downward velocity would be enough to turn the screws. The screws do not have an electric motor, it's a pulley system powered by the downward motion of landing.

any speculation on why the thrusters and harpoons failed?
At one point I believe i read that the harpoons had been motored back in, as though they had fired but didn't catch anything.

I was initially thinking it might be some methane semi-liquid or something similar, but it's definitely compression artifacts.

Look at the image from the panoramic release (cropping and rotating area of interest):



The shimmering is gone...

http://www.esa.int/var/esa/storage/images/...t_panoramic.jpg

They are considering it, but they might have to wait a few weeks or months to get enough battery power, IF they do not use the last few amp hours to do a hop. But I think they are running out of power, they say even tonight's comm link is doubtful, which seems a bit earlier than expected. Also they said a command to enter low power operations failed to get to the lander. I think the battery warming is taking more power as they only have 1 hour 20 mins of sunlight per comet day.

They don't know yet. That can take low priority as they are collecting science right now.

Yes August 2015 is when the comet is closest to the Sun. The mission has 1 or maybe 2 more years to run. The lander is one small complimentary part to the whole mission.

Oh darn it takes 5 or 6 hours of sunlight just to warm the battery up to 0C, so there is pretty much zero chance of any battery power for even transmissions. Until of course the comet heats up.

Philae is drilling, from twitter.

Agree with you MahFL : once the S/C is frozen, well... it's almost dead for ever. And if not, it's very likely a transmission failure : you cannot listen to it anymore because the frequencies may have shifted also. My feeling is that, if Philae stays where it is now, getting contact with it in the future will be very unlikely.
This is why some are thinking about moving the landing gear to try moving the S/C out of its resting place. If they do, this will exhaust the energy in the batteries and Philae will (maybe) hop silently to another place. Then we will have to wait more days, hoping that its new resting place will be located where there is enough sunlight to charge the batteries and start telecoms again.
In my opinion, this would be the "last-chance" effort to save it.
Like in real life, if you see someone in real danger, you'll do everything you can to save him/her... In any case, we have nothing to lose...

Imagine dry ice sublimating in a beaker; there is no liquid phase representing transitional warmth--the solid remains its same temperature until it is gone, regardless of the ambient temperature which only affects the rate of its demise. By analogy, I doubt that the nucleus material itself will warm appreciably. If super-cold ice can exist in a permanently shaded crater on Mercury, I myself cannot be as optimistic as others about improvements in Philae's environment.

Here's how I assess things so far: The data we've already obtained is already immensely valuable. Use of the flywheel may come down to publicity ("well, we tried") than expectation of escape since appreciable power would need to be expended to accelerate that mass, and there is no steering or understanding of what might be blocking the top side. I'd rather see the remaining budget used for more MUPUS activity and higher-resolution images. Let's let the team do the best they can with the resources they have, and then hope we can get a glimpse into some of this great data at some point.

Here's three views of the presumed final resting place, rotated to match:

Click to view attachment

Nothing to risk trying to shift the position if battery power is too low to do more science. At worse it's dead, at best it jumps to a better location in working condition.
We know that it can jump easily and that damage is unlikely.


About the landing site location: interesting that it came down at a place where those boulders also seem to have been deposited.

The worst-case is probably in the deep shadow at the far right of the red ellipse, that's dark in both images...

Here's a summary of the "ESA Hangout" session i found:

Summary

*Simulations suggest battery power will last long enough for tonight’s data transmission from Philae between 21:00 and 23:00 GMT.
*Esa is considering whether to spin Philae’s flywheel (designed to keep the craft upright during flight) to ‘bounce’ the lander into a new position where its solar arrays will get more sunlight to recharge its batteries.
*80-90% of the intended science will have been carried out, but there’s some doubt over whether all the data will be uploaded before the lander loses all power.
*All the lander’s instruments are working well. MUPUS and APXS instruments were used last night and the drill was activated. Esa will know this evening whether drill samples have been taken successfully.
*There will be more CONSERT radar data tonight, which will be used to try to locate Philae.
*As the comet reaches its closest approach to the sun next year, there may be enough power from Philae’s solar panels to wake up the lander.
*84 images of the comet are being awaited from Rosetta, which will be used to try to locate the lander. There will also be descent and touchdown images relayed from Philae to Rosetta.
*A manoeuvre command has been sent to Rosetta to keep the Philae landing area in sight over the coming days

Bibring etal state that it is wavelet compression. They list a typical compressed image size of 1.2 Mbit per 1 Mpix, 10 bit/pixel frame. So that sounds like pretty high compression.

About seeing the same compression artifacts in the panorama, that's reduced in size and jpegged, so you may be seeing some jpeg artifacts on top of the wavelet artifacts.

I wonder what the fuel budget is to keep Rosetta in view of Philae?
The comet must have a pretty wonky gravity field...

Since writing above, via the live blog, the constraints on Rosetta have been explained. A big consideration is protecting Rosetta from the expelled gas and debris from the comet....

Astounding that so many team members were willing to spend an hour fielding questions at such a critical time.

One other tidbit I noticed was the suggestion that the lander is currently oriented with its body's z-axis (the direction perpendicular to the plane of the legs) pointing close to where it would have been pointing had it landed at the intended site. This helps communication with the orbiter.

This information and the thought of a two hour bounce gives me the impression we've been ridiculously lucky to get anything at all back from the lander.

Another view of the putative "resting place". Image from 14 September.

Click to view attachment

great find, but if you align via the straight ridge that bisects the crater, i think the ellipse and diamond would both be at the top, 90 degrees away

ADMIN EDIT: Unnecessary quoting removed. Please do not 'quote' if it immediately precedes your reply/comment. Board rule 3.5

Yes, also heard yesterday that the lander's orientation was more or less vertical.
If it has landed on those cliff faces, the "open sky" image make sense. It's simply a direction where the surface is much lower.

From Philippe Gaudon in a CNES press conference (in French), it seems the shutter of the APXS didn't open as the data is showing titanium and copper which what the shutter is made of.

https://www.youtube.com/watch?v=GH53CGkPTAI#t=528

Here's the (rotated) relevant bit of search area from: https://www.flickr.com/photos/europeanspace...cy/15549511085/

(the end of the 'ridge' enters from the lower left)

Click to view attachment

Merci Rakhir, très instructif.

WOW ! Thanks a lot Rakhir : a conference even better than ESA's at noon which was almost -unfortunately- "news without news".
Save from the APXS shutter problem, the other engineering aspects shown by CNES people are much more interesting and let us imagine much more the situation foreseeable for Philae and science to come : they reveal fascinating new science research induced by the 3 "hops" I could not even imagine in my wildest dreams !
Now, you really understand why they look so enthusiastic.
Thanks so much for this link !

All quiet on most fronts. The MUPUS team has signed off for the night with this enigmatic message:

"Note from PI: Despite we lost active thermal conductivity measurements due power shortage ...
..we are quite happy with the performance of our instrument .."

and this: https://twitter.com/Philae_MUPUS/status/533344713437634560

"We are proud of our little [ed: experiment?] up there in the cold ice desert of Churyumov-Gerasimenko.
Hopefully we'll be back for the long term mission."

I don't know quite how to read that, but cheers for all that they and the other teams have accomplished on a tight schedule. Since this statement seems based on engineering data from the lander, we might expect some hopefully-not-final science data has at least been uploaded as well. Public results after the 9:00 am CET team meeting.

Hopefully it just means that they had to scale back their activities due to the power budget.

This is nice, but I think the main candidate landing site is out of this picture, outside the lower Right corner?
See your (Jorn Barger) "bounce diagram" with red arrow, Post # 511.

I don't know if it's of much help in locating Philae but the lander's magnetometer ROMAP recorded the touchdown events with clear spikes in the data:
http://www.igep.tu-bs.de/forschung/weltrau...a/comet_en.html

I'm wondering if the second bounce wasn't flying into a cliff and dropping from there?

Yes, the original only caught the right half of the red ellipse, but the resolution is great for that half

NAVCAM got the bounce mark at the target landing site:
http://blogs.esa.int/rosetta/2014/11/14/ph...een-by-rosetta/

It will look great with OSIRIS for sure....

Is that the whole image? If not, a larger view would probably show Philae before landing since he was only 250m from there and/or after bouncing since second image was taken less than 2 minutes after touchdown.

I think a key quote from the Rosetta blog post on this set of images is this:

"With thanks to Emily Lakdawalla of the Planetary Society for helping with the image processing."

Go Emily!

So close after contact, Philae might still be visible in the cropped second image.
Marked a candidate, distinct from pixel errors:
Click to view attachment
Credit: ESA/Rosetta/NAVCAM, CC BY-SA IGO 3.0
modified by "Gerald"

Just a few days as guest at ESOC, already in the team; great, Emily!

There's buzz on the internet that a hop to move Philae is planned. Will they or wont they?

http://www.theguardian.com/science/2014/no...ander-hop-comet
http://news.discovery.com/space/philae-to-...ival-141114.htm

Seems only turning for now

Turning Philae

Well spotted. I didn't notice that. now I wonder if bright spot is Philae and dark spot its shadow.

I would expect the lander to be brighter than comet material, not darker. Unless it happened to be out of the frame at the time of the 2nd image (the lower left edge does suggest the navcam might not have been centered on the landing point?), it ought to be visible somewhere, given that it should have been less than 50m above the surface during the bounce.

Edit: what Emily said.

They have a signal from the lander on this pass...

https://twitter.com/elakdawalla

Question is given battery state will it last the full pass... iffy....they said 20 watt margin was all that was left in the batteries earlier - primary secondary and solar are all tied but it can't have much power left..

if you draw a straight line thru those two points, where does it cross the blue diamond?

SIGNAL IS BACK telemetry & science data are flowing from the surface !

You shouldn't assume that a ballistic trajectory would be seen as a straight groundtrack as seen from Rosetta's vantage point.

Science from an alien world: COSAC instrument data now flowing from Philae.

!! Great news: Ulamec to COSAC team: plenty of COSAC Science packets coming in now!!

That's really good news!
So there is still battery power, and we've a chance to see compositional data.

Drilling worked too!
https://twitter.com/RosettaSD2
Now to see if anything was taken in...

Can't be much left...be interesting to see if this turn is successful...probably the last best chance with the remaining power

So they got a lot of the science done. I can't wait to see what the gas analysers find.

And they still got some power left for rotating and maybe more.

Rotation command sent gear up -- this pass is 3-4 hours of com time...last best chance for continued life...

now all we have to do is wait...