Rosetta's comet mission discussion thread

In summary: The landing is expected to occur on Wednesday, November 12th at 12:35am PST.The Rosetta mission is a European Space Agency (ESA) mission with some US instruments on board. It carries a lander that will descend onto the comet surface, take pictures at the surface, and study the comet. The lander's feet will have to drill into the comet material in order to be anchored firmly, because the gravity is very slight.
  • #36
marcus said:
What I think now is that all they have to anchor with is the two harpoons they have been talking about.

I don't have a clear picture of the mechanism. Also I heard a disconcerting bit of news announced from the Lander control room at Köln.

They had an unexpectedly soft landing, which seems good. But when they tried to fire the harpoons, either they did not fire, or they fired but did not take hold. The speaker said they were now studying the situation and considering whether to try again.

Does anybody have a diagram of the anchor mechanisms?

Have a look at this : http://www.esmats.eu/esmatspapers/pastpapers/pdfs/2003/thiel.pdf
 
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  • #38
Does anyone know what are we going to see next? All I see now is people working at some computer lab and talking.
 
  • #39
Also check out these videos about the orbital maneuvers performed during the mission.





Hope I could perform any of these in KSP!
 
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  • #41
Greg Bernhardt said:
Yashbhatt those videos really put into perspective how bonkers awesome this achievement is!

Ya. I was like staring with open mouth when I saw so many gravity assists and the the staggering complexity of maneuvers. But I did not understand why they performed a maneuver to get out of the original orbit plane and then back and so.
 
  • #44
I was up until 4 am this morning, catching up, and watching videos.
I'm having technical difficulties embedding my favorite video I saw, so you'll have to just Google:
"Demonstrating Rosetta’s Philae lander on the Space Station"

It's on youtube.
 
  • #45
OmCheeto said:
I was up until 4 am this morning, catching up, and watching videos.
I'm having technical difficulties embedding my favorite video I saw, so you'll have to just Google:
"Demonstrating Rosetta’s Philae lander on the Space Station"

It's on youtube.

Talking about this one ?

 
  • #46
Yashbhatt said:
Talking about this one ?


Yes!

Thank you.
 
  • #47
See this everyone : Slooh is now showing the comet on which Rosetta landed. Live!

http://live.slooh.com/stadium/live/rosetta-harpoons-comet-67p-churyumov-gerasimenko

The small animated movie they have created is very cute.
 
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  • #48
links to some side information:
http://en.wikipedia.org/wiki/Philae_( spacecraft )
http://nssdc.gsfc.nasa.gov/nmc/ spacecraft Display.do?id=PHILAE
My rough guess is that the gravity where she is is about 1 mm per second per second. or about 1/10000 of a gee.
the mass of the lander is about 220 pounds, so the weight force would be about 0.02 pounds.
I could be off by quite a bit, can someone help with more accurate estimate of the comet's mass and surface gravity at the landing site?
EDIT: A Reuters article gave the estimated gravity as 1/100,000 of Earth gee. That sounds more in line with the estimated escape velocity of 1 meter/second. If that's close to right then the Lander weight is more like 0.002 pounds. 0.03 ounce. Sorry, I'm boggled. Maybe Reuter's and I are mistaken, but if we're right how can the lander not be blown away by sublimation as the surface warms?
 
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  • #49
marcus said:
links to some side information:
http://en.wikipedia.org/wiki/Philae_( spacecraft )
http://nssdc.gsfc.nasa.gov/nmc/ spacecraft Display.do?id=PHILAE
My rough guess is that the gravity where she is is about 1 mm per second per second. or about 1/10000 of a gee.
the mass of the lander is about 220 pounds, so the weight force would be about 0.02 pounds.
I could be off by quite a bit, can someone help with more accurate estimate of the comet's mass and surface gravity at the landing site?

This might be helpful. http://en.wikipedia.org/wiki/Philae_( spacecraft )
 
  • #51
marcus said:
links to some side information:
http://en.wikipedia.org/wiki/Philae_( spacecraft )
http://nssdc.gsfc.nasa.gov/nmc/ spacecraft Display.do?id=PHILAE
My rough guess is that the gravity where she is is about 1 mm per second per second. or about 1/10000 of a gee.
the mass of the lander is about 220 pounds, so the weight force would be about 0.02 pounds.
I could be off by quite a bit, can someone help with more accurate estimate of the comet's mass and surface gravity at the landing site?
Marcus, alas, gravity at the surface is equal to 0 (zero).
Chance only: enable the jet to fillet, fillet to flatten the surface, drill, drill two or three holes and drive there are two or three garpupa. All. The engine can be turned off.
 
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  • #52
There was some engineer on Slooh who said that even though of the harpoons have failed, the comet will remain on the surface.
 
  • #54
EU2AA said:
Marcus, alas, gravity at the surface is equal to 0 (zero).
no, the comet has mass, its gravity is non-zero, its just very small
 
  • #55
Yashbhatt said:
There was some engineer on Slooh who said that even though of the harpoons have failed, the comet will remain on the surface.
Yes, the comet is not going anywhere. But we are talking about Philae ...
 
  • #57
  • #58
Yeshe has a chance

It is possible that the engine is still running Philae?
It is possible that at least one harpoon can be recharged.

Then you need to download a new program at Philae:

- Landing soveshat harpoon forward as whaling boat;

- Aim your harpoon AML large stone such BLD;

- Shoot harpoon before touching the surface.
 
  • #59
davenn said:
no, the comet has mass, its gravity is non-zero, its just very small
MIB!

Frank also points out that humans must learn to understand the notion of scope in the universe; i.e. a very important and grand thing can be very small.

Ok. This might be a bit of a stretch in my "movies can inspire people to think" mindset.

But, um, I'm going to take a nap now.
 
  • #60
Given that it apparently bounced and that the momentum flywheel was being spun down, I hope that any "final" landing will be the right way up. I'd have thought a shape like that would only have a small chance of landing on its feet if it started tumbling.
 
  • #61
Dotini said:
A friend on another forum informs me it's on the surface, but moving around some.

It's a Rover! :)
 
  • #62
This so cool. :)
- Oops OK, looking at the news again!
 
  • #64
The latest that I am seeing from the ESA site is the notice of touchdown by the Philae probe. Is there anything more recent information available?
 
  • #65
It's hard to find anything other than some unofficial speculation about Philae having bounced when it landed.But that aside, I think that it may be possible to get some good estimates of how the comet's gravitational field varies. The Rosetta team has released a 3D model of the comet, Measuring comet 67P/C-G | Rosetta - ESA's comet chaser, and one can use a voxelizer like "binvox" on it to find a voxel representation of it. A voxel is a 3D pixel. One can then calculate the comet's gravity by assuming something like constant density then integrating over the voxels found for it.

http://www.cs.princeton.edu/~min/binvox/ is open source, but I've had trouble getting it to work in OSX Yosemite, the latest version. Even compiling it has trouble.

From Rosetta's motions, the Rosetta team has likely calculated some of the multipole coefficients of the comet's gravitational field. But I haven't seen them published anywhere.
 
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  • #66
SciFi channel said they picked site J. Not sure but I think it's on top of the large lobe.
 
  • #67
Emily Lakdawalla, Senior Editor & Planetary Evangelist, The Planetary Society. Planetary scientist, writer, public speaker,
is in Darmstadt Germany making reports via Twitter also.
I don't think she sleeps.

IMG_0359_pp_square_normal.jpg
Emily Lakdawalla @elakdawalla · 7h
! ... ! ... ! RT @Philae_ROMAP: @Philae_ROMAP magnetic field analysis revealed 3 landings at 15:33, 17:26 and 17:33 UTC

IMG_0359_pp_square_normal.jpg
Emily Lakdawalla @elakdawalla · 11h
I seem to have picked up >5000 new followers today :O Welcome, all of you, and I hope you like planetary exploration and space photos.​

One of them was me.

I was just listening to a BBC broadcast recorded yesterday following the landing. One of the commentators said that the landing itself was an experiment. ~9:45 - 10:15.
At 44 minutes, it's a bit long, but they discussed a lot of interesting things, with a lot of excited scientists.
 
  • #68
Greg Bernhardt said:
Google changed their logo doodle to a Rosetta animation
they rushed
 
  • #69
I've not yet seen a photograph taken from the landing site...
 

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