Perhaps on Earth but define vertical on a body with a negligible gravitational field where the material below the surface is out-gassing. If you heard during one of the media events ROLIS member Stefano Mottola noted in the image from ~40m (IIRC) above landing site #1 that the dust appeared "active", partially covering one of the boulders in view.

Reading the early science results from Rosetta starts to make a lot more sense. e.g.;

http://www.planetary.org/blogs/emily-lakda...-darmstadt.html

"@ESA_Rosetta sees strong diurnal variation in vapor production. Probably from first 2 cm of surface #DPS14"

"MIRO sees "porous, dusty surface that is incredibly insulating"You only need to go down a mm or 2 to go down 50K in temp #DPS2014"


Indeed as alluded to in the MUPUS tweets similar material to where Philae ended up possibly underlies the first landing site, hence the bounce.





A guy at Jodrell has done a difference image to bring it out.
https://twitter.com/Eamonn_Kerins/status/533967071705448448

There is so much chatter on the internet, "it is fool's errand" to try and sort through it all.

While following the MUPUS discussion here and on twitter, I found this blog entry from Rachel Feltman at the Washington Post. I think it is a decent review of the significance of the events of the last week.

Why we all fell in love with Philae

Or if you prefer the twitter link:

Washington Post twitter link

Looking forward with healthy optimism, will Philae simply wake up once it's received enough sunlight? Or, will it need a signal from us to phone home?

edit: ESA blog answers this question.

Confusing comment in that post:
This would mean that the dark landing mark wasn't permanent, but dissipated over the hour, as if it was just a cloud that dispersed. Still it's surprizing that the dark mark would apparently completely disappear, leaving no bounce mark or debris field visible on the ground.

I don't find this second image convincing as a definitive sighting of Philae. There are stronger shadows in the second, later image. Maybe the bright area and shadow are just some natural feature more easily seen with the shifted angle of lighting? Or perhaps the initial lander bounce threw some debris to the location suspected as Philea itself? I'm sure there are several other equally plausible explainations for the difference between these two images.

Furthermore, what happened to the 1 km estimated separation of the first bounce location to the second? How far apart is this purported location of Philae from the area disturbed from the initial impact? Less than 100m? Less than 50? It seems very unlikly that a bounce of several hundred meters vertically would not have any appreciable horizontal drift considering the rotation of the comet nucleous and possibly uneven terrain from which it bounced. And what of the signal triangulation results that placed the final location much further over at the rim of a large crater in very rugged terrain? That seems to be a much closer match to the surface imagery than the smooth-appearing area targeted for the landing and at the supposed final location.

I'm surprised this blog got posted with such confident language. Sure, I suppose it _could_ be Philae, but I'd think folks would want to go over it a lot more, especially if other evidence contradicts it.

I'm not trying to diminish this spectacular achievement. I'm glad to be alive at a time humans could send something out to touch a comet!

What other evidence? Your numbers that seem to be pulled out of thin air? There is an official number floating around for the estimated bounce-off velocity. There is a known time for the image timestamp and for the landing time. A fairly accurate height estimate can be made for Philae at that point in time, an exercise that I'll leave to the reader.

Furthermore, I would hope the ESA team have a better idea of where the vector normal to the surface (and thus which groundtrack direction Philae was actually going to) points in that image and whether or not this particular trajectory is consistent with the final resting point. To quote the blog entry:

bold mine.

This should be a plausible explanation, starting with

of the Rosetta blog post:
The dark mark is the shadow of a cloud of debris, which has been dense that shortly after the impact.
An hour later the cloud has been dispersed or settled, no obvious shadow visible any more.

Nothing happened to it. The 'after' image is - to cite ESA themselves " 1 min 26 seconds after first touchdown"

Assuming an approx 1km traverse across the comet in the 113 minutes until the second bounce..... that 1min 26sec should only be 13 meters from the first touchdown point.

That correlates well with what we see in the image.

This fits the new, 'photographed' direction much better than mine-- it's the far end of the blue diamond.

With the primary battery designed for the decent to the surface and first few days of surface operations depleted, the solar panels were intended to be used to recharge the backup batteries. So could the 90 mins of daylight (possible more after moving the lander) recharge the battery after maybe a week or two - can they hold onto that little bit of charge they receive each day? Or would they discharge ones it moves back into shadow. - this is probably wishful thinking !!!

ADMIN EDIT: Unnecessary quoting removed. Please be mindful of rule 3.5

Thanks xflare for your question.
What I've heard is that it will take at least a month, if not 2, to have the batteries fully charged. So the CNES team is not expecting to receive signals from Philae soon...

ADMIN EDIT: Unnecessary quoting removed. Please be mindful of rule 3.5

Someone said they have to be heated to a minimal temperature to even recharge, so this wouldn't work.

ADMIN EDIT: Unnecessary quoting removed. Please be mindful of rule 3.5

The main Solar Panel lady said it takes 5 or 6 hours to warm the battery up to 0C, so right now the battery won't even be close to being warm enough to be charged up. The hope is as the comet gets closer to the Sun the amount of warming the battery needs will be less. The main reason the lander would have failed would be over heating as the comet gets closer to the Sun, but as we know it's in a shady spot.

Re: warming the batteries

I was trying to find information online on this. Not totally clear to me, by this document states that there is a "warm" compartment and a "cold" compartment, the warm compartment evidently kept that way with passive heating:




Right now 67P is at about 3 AU. It'll reach 2 AU in about 4 months, which should about double the the insolation.

OSIRIS spots Philae drifting across the comet

Wow.

Ugordan, djellison: Thanks for taking the time to attempt to clarify things for me. I was posting based on this statement in the postscript in the blog entry:



So I took the postscript to mean that the image was taken long after the bounce. If it was taken an hour after the bounce, I did not find it highly likely to be so near to the initial impact point. If the image is really just a minute or two after the bounce, obviously it increases the chances of the sighting of Philea dramatically. It would also provide a good directional vector to search for the final resting point.

So is Philae at rest at 15:43 in the latest image, or still going? Here's the 15:43 location in wider context (red dot):

Click to view attachment

Yeah... Wow! Between the 15:35 NAVCAM image released earlier with the dust cloud and the 15:43 OSIRIS image here, the dust cloud seems to have dissipated to show imprints of the 3 footpads as well as the main lander body in the center. So cool !! It's not as simple as drawing a straight line connecting the dots because the lander is above the surface at different altitudes in the images, but it shouldn't take too long now to locate the lander's final resting place.

Sohl, the empty image that was supposed to show the landing point immediately before touchdown was mistakenly showing an image taken long after the bounce, after all the dust has settled again. For the purposes of analysing the other image - which was taken roughly 2 minutes after bounce - I'd say that's pretty irrelevant.

Incredible images.
Poor little guy looks like he went straight into that dark cliff at the edge of the image.

At that point in time, it was still going up at a hefty pace. What happened to be in the background at that point says very little. Given the (presumably lumpy) gravity field of 67P, I still wonder whether CONSERT ranging and triangulation data pinpoints its final position better than 2 images taken shortly after the start of the Big Bounce.

Before/after enlarged 400%


The marks seem wider apart than the footpads, and not at the same angles - it must have had some lateral speed and rotation.

I think that the ground track can be calculated from the NAVCAM/OSIRIS images at 15:35 and 15:43 once they can determine Philae's respective altitude and speed and it will help with CONSERT to further triangulate it's final position. They will need to use Rosetta's exact location in space when the images were taken and a shape model of 67/P to determine where the other end of the parabolic trajectory is, but it can be done. Way above my pay grade though.

The uneven gravity field would blur the ground track somewhat, but not significantly since it appears to have stayed on the head of the comet.

Finding out the path makes the landing even more amazing. Philae could have easily came down on that bolder or hit the cliff and yet it survived. I have to agree with the team that so many things could have gone wrong, it is amazing it went so right!

You are probably right. It had to have some lateral speed to rebound at an angle from the surface. I think the shallow depression in the center is from the lander body. I don't know what the ground clearance is, but it doesn't look like much.

In that last cut-out image of Philae over the shadowed area (at 15:43), it still has a long way to go. It will travel for a further 1 hour and 49 mins before reaching its
final resting place at 17:32.

No, it's still flying.

The gear is designed to flex, remember the impact would have been really gentle, so even if the body made impact no damage would be likely.

There are various papers that explicitly states the gear is designed to take the landing loads, but could well bury itself (the landing gear) in the process.

New version with a very un-scientific cutout of Philae from the 15:23 frame 11 minutes before touchdown.

Didn't resize Philae even though it would be about half a kilometer farther away

If Philae came in from the left, it looks like it dragged its two left feet. There may something similar in the right foot, but it is less apparent.

I think the bigger central depression is actually the main Philae body rather than a leg.
The fourth smaller trailing mark, which is either a double or triple cluster of little depressions, is the last leg to hit with less force, after the other two and
the body took the brunt of the (gentle) impact.

Based on the new OSIRIS images, it appears Philae is heading in a different direction then proposed by the initial CONCERT prediction (i.e. the blue diamond).

No, I think we are seeing Philae on a curved track passing through different altitudes, viewed obliquely. So we cannot infer the ground track from that.
Hence a straight line drawn from the initial touchdown point to the 15:43 position does not give us the direction of travel.

ADMIN EDIT: Unnecessary quoting removed. Please be mindful of rule 3.5

Yes, Philae could definitely be on a curved track. However, as far as the obliqueness of the view goes, the view is from above looking down to the north (relative to the image). So in the image at 15:43 the lander is actually more south relative to the the ground then appears in the image. Of course I could have the geometry all wrong, but that's how I see it

I've approximately registered the two first bounce site navcam frames and the post-bounce OSIRIS frame - here's the resulting animation:
Click to view attachment
There are a couple of things of note. First, comparing the navcam "dustcloud" frame with the OSIRIS frame, you can see that the dark splotch extends towards the bottom of the frame from the actual touchdown triple mark. This is consistent with the splotch being the shadow of dust kicked up by the bounce, given that the sun is shining from roughly the top of the frame.

The other thing is that there's no hint of the triple bounce mark in the other navcam frame, although if you look around the frames other features of similar size and contrast are (barely) visible in that navcam frame. Of course it might just be a coincidence of pixel noise cancelling out the triple mark in the navcam frame. But I still wonder if the PS in the caption of this post, which says the other navcam frame was actually taken an hour after the bounce, is incorrect. Notice that the other text on that page and on this image page posted after the blog post still state that the other navcam frame was taken before landing. Also, I can't see any change in shadows between the two navcam frames, whereas if they were taken an hour apart there should be a large change - that's one twelfth of a C_G day.

More picts of Philae before and after landing: http://blogs.esa.int/rosetta/2014/11/17/os...ross-the-comet/

Click to view attachment

I thought the same at first, but I think the orbiter is roughly following Philae's ground track because the 3 prior photos are lined up with each other and the landing site.
Rosetta's camera is therefore looking more or less straight down.
After the first touchdown this all changes, and Rosetta continues upwards towards the top of the picture, and is therefore looking somewhat back (down towards the bottom of the picture) at an increasing angle post-landing. Of course Philae could also have bounced off in a somewhat different direction from its line of approach.

WOW... incredible images, incredible mission.

Anyway my take on the initial landing site, overlay of ROLLIS and OSIRIS images showing a before and after. Looks to me like the lander might have caught a strut on that meter sized rock in the landing footprint.

Click to view attachment

Nice GIF, Jam Butty

One could almost speculate that the slab like 'rock' on the SW corner of the touchdown point has been kicked up significantly by bounce 1 - perhaps it kicked the lander to a harder 'slap down' with the other two legs which triggered the bounce.

I wonder if Philae's shadow is visible in any of the OSIRIS images. It wouldn't be in the tight frames they cropped, but it's worth looking for.

Given that we have SPICE information, I'm wondering if someone could produce a table giving altitude and sub-spacecraft lat and lon for both Philae and Rosetta in 5-minute time steps for the landing phase?

Interesting that Philae looks to have changed direction after the second touchdown. Presumably still headed toward the triangulated diamond after that?

If you look at the Rosetta insertion trajectory modeling you see as you mentioned that Rosetta's motion is in the same general direction as Philae. However, that continues for a certain amount of time after first contact because the comet is rotating in roughly the same direction. At least until the landing position rotates past Rosetta.

I added the 4 landing dots of the last image provided in the somewhat bigger picture. This gives a better overall direction of Philae after the bounce.

Click to view attachment

Philae was supposed to touch down with near zero horizontal velocity. So, why such a big change in direction occured? Is that due to the rock in the way as suggested a few posts before and/or because the terrain was not as "flat" as we suppose it is?By the way, those views of Philae from Rosetta remind me of Phoenix seen while landing. And I hope Philae IS a phoenix . We'll see.

COSAC PI: Drill tried to deliver sample. Ovens heated up. But data show no actual delivery. "There’s nothing in it."

https://twitter.com/erichand/status/534413817040867328

I was actually curious about that myself. It could be because the lander did have a small amount of spin to it or more likely that the terrain there was actually sloped in that direction.

Supposedly a gyroscope effect kept it level (like a frisbee?), but all my intuition sees is every tiny asymmetry sending it tumbling out of control.

And if we extrapolate the direction we have from the picture with the six inserts (my post above), and match this on the bigger view of the 'head' of P67, we get a rough idea of were Philae could have made the second and third bounces.

We can estimate that there were a good 11 minutes from first touchdown to the last insert position at 15:43. What we only approximately know is how Rosetta was positioned when taking the picture with the 6 inserts: probably about straight up. So the following is a non scientific guess of where it landed. It could be even more to the right of the picture, which then would mean it is at a totally different place 'way beyond the corner', given more to the right means more towards the side of the head or the neck.

White circle is not mine (was in the ESA picture, rotated about 100 deg counterclockwise). If you enlarge, you'll see I mapped the first landing point and the 15:43 position here.

Click to view attachment

I thought of an image processing project I really want to do but sadly don't have time for, so I'll drop the idea in here in case anybody else wants to give it a go.

Take the OSIRIS 3D image of the landing site (you can get left and right channels separately there)

And the OSIRIS images of Philae during descent and bounce

And place images of Philae into the 3D landing site image in positions matching ones in OSIRIS images, adding in parallax to make it pop out of the screen.

With a good model of the comet to triangulate against, I suppose that they have two points nailed (XYZ coordinates) in the first bounce trajectory--the first touchdown site and the 15:43 shot and the time between them. That would strongly constrain the possible trajectories. I'd bet that when the known time of flight to the second touchdown is factored in, they are homing in on the spot.