Philae landing on the nucleus of Comet 67P C-G Options

[mcgyver]

Did this really happen?
http://www.seti.org/weeky-lecture/rosetta-...mov-gerasimenko

Yes, Philae bounced totally uncontrolled twice before finding a rest in its final and currently unknown position.

[belleraphon1]

Interesting...

Hunt for Philae hangs in the balance - Rosetta mission would have to sacrifice other science to search for comet lander
http://www.nature.com/news/hunt-for-philae...=TWT_NatureNews

"Scientists at the European Space Agency (ESA) are debating whether to change part of the Rosetta mission in what would probably be the last attempt to find lost comet-lander Philae — but the shift would mean sacrificing long-planned science."

Craig

[Habukaz]

The impression I get is that not finding Philae will have minimal impact on whether or not contact is re-established with it.

[belleraphon1]

Me too...

I would go for the planned science .....

[omero]

Yes, Philae bounced totally uncontrolled twice before finding a rest in its final and currently unknown position.

Indeed, that the lander bounced at least twice and possibly "shaved" a rim, a boulder or some other feature in between the 1st and the 2nd "bounce", before Philae eventually settled down on the surface of 67P seems to be confirmed by now... That's all we've been told thus far.

What's not clear it's the trajectory Philae followed just after the 1st bounce.
So many confusin reports... It jumped back as far as 1km, as far as half a mile... As far as ... For as long as...

As the Admin correctly assumed, I was just curious to know if anyone had "first hand information" on what was said in that particular SETI talk event. No video of that SETI's talk event, [btw: thanks jmknapp] has been uploaded after over a month, while their claim is that it usually takes 1-2 days before a video of (an) event gets uploaded/published.

I was just curious to learn if more (ACCURATE) information was disclosed, information coming from instruments on-board of the lander itself.
Hoped that SETI talk revealed some measurements (even APPROXIMATE)... Still waiting

[surbiton]

I just took a glance at the view from Rosetta towards 67P during the ~2 days after Philae's landing, using STK & the SPICE data.
..................
Whether and how this different positioning of Rosetta for a longer communications window would have worked would depend on the details of Philae's final position, which of course we don't know even now. Whether it would have been a good idea is another question yet. But I do think it would have been possible.

Thanks for such a detailed post.

Would I be correct that since 67P rotates every 12.4 hours [ 29 degrees per hour ], and if I recall correctly, Philae was receiving sunlight for about 90 minutes each day [ I don't know if it was earth day or comet day ] , then the sunlight window is only about a little more than 40 degrees wide ? In other words, it is in a hole as has been speculated by many. If it is known which solar panel received sunlight for what lengths of time , a rough "shape" of the "hole" could be cinstructed. Since Philae is resting at or near the equator, the sun should be high in the sky at 67P's "noon" at that spot.

[scalbers]

It seems more like shadowed by cliffs as the CIVA mosaics (see earlier posts in this thread) show a clear horizon in certain azimuths. 4th Rock also posted some info about the solar panels.

[Sherbert]

Two new images from ESA today. The first a NAVCAM view which includes a view of the Philae landing zone. Although a lot more of the area below the rim of Hatmehit is visible most of the CONSERT search zone is still stubbornly in shadow. The sunlight is getting closer though.

https://www.flickr.com/photos/124013840@N06/16373930901/

The second image is of a couple of dust grains collected by COSIMA. Fascinating they are too, revealing a great deal about the structure and makeup of the cometary material. If, as the team has suggested, the "dust" is sublimation residue, if you fill the spaces in these grains with volatile ices and a a few organics, what you have is a close approximation to what the whole comet is made of. Basically tiny micron sized bits of sodium rich silicate dust particles held together by sintered, frozen volatiles, with a potpourri of organic chemicals mixed in.

The suggestion is that the smaller sub grains, the larger grains are made up of, are your basic interplanetary dust building blocks. I know there is some theoretical size limit set by the various nebulae accretion models for this basic refractory dust, it would be interesting to see how they compare.

[jmknapp]

The Dec. 16 SETI Talk The Rosetta Lander (PHILAE) mission: landing on comet 67P/Churyumov-Gerasimenko by Philae Lander Payload Manager Dr. Jens Biele finally posted to YouTube yesterday:

https://www.youtube.com/watch?v=tQLtAp1Aw48

A lot of it is review for those closely following the publicly released information to date, but there is some new information. One item of interest is that they think the harpoons failed to fire due to some miswiring so that the commands they executed weren't in the proper sequence. If true that would mean that with a modified sequence of commands they might still get the harpoons to fire, which would be of scientific interest if nothing else, since the harpoons have accelerometers and sensors that could get data about the subsurface down to maybe a couple of meters.

Attached below are some slides showing the reconstructed trajectory.

[Habukaz]

Couldn't the harpoons potentially also be used a last-ditch effort to move Philae out of its current position as the comet heads back away from the sun? (assuming they don't end up anchoring it as once intended..)

[jmknapp]

That came up in the question period & he seemed to acknowledge the possibility that the recoil might reposition the lander, but per his description of how they work, the harpoons come out at 70 m/s and would penetrate and anchor even in sandstone, and down to 2.5m in softer stuff, so maybe it's unlikely that the lander would go anywhere?

[MahFL]

They could try a hop first, the person who designed the landing gear says it can make the lander hop, if they have power of course. Also it could flip it onto it's back too......

[omero]

Many thanks, jmknapp! The SETI page of the event (which I kept checking again and again until this morning) still hasn't been updated with a video...

[djellison]

It may well never be - occasionally speakers ask that a talk not be shared or put online. That text may be boiler plate for all presentations they host.

[jmknapp]

The web site lags behind YouTube usually. They also don't show the video for the Jan. 20 talk A new model for the origin of life: Coupled phases and combinatorial selection in fluctuating hydrothermal pools but it's on YouTube.

It's best to subscribe to the YouTube channel for updates.

I was wondering if the delay was due to waiting for clearance from ESA or whoever.