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Rosetta Comet Orbiter -** 120 Icy Patches ** Philae Phones Home ** Ceres Fly Over Video ** New Coma Discovery ** Picture MOTHER LODE !
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In accordance with industry accepted best practices we ask that users limit their copy / paste of copyrighted material to the relevant portions of the article you wish to discuss and no more than 50% of the source material, provide a link back to the original article and provide your original comments / criticism in your post with the article.
[quote:Reality420:MV8yNTk4OTk2XzQ2MTUzMDcxX0RGMDU5MUEw] [quote:K Hall:MV8yNTk4OTk2XzQ2MTUxMzg5X0ZFMDk3MzhG] [quote:TheWatcher-Anonymous Hero:MV8yNTk4OTk2XzQ2MTM1MzY5XzYwQTgzQ0Y2] I still have a concern about what surface the lander will be landing on: Ice? Rock? Frozen CO2? ..Partially frozen CO2? What impact will the landing surface have on the mission? [/quote] You are in good company, the Philae lander team are concerned too. You can see in the above video, at around 37 minutes, Valentina Samodelov answers a question about the landing systems and surface composition. If I can mix up what we know with my own speculation: My estimate for the comets bulk density is around 0.5 g cm-3. That is about the same as hard packed snow or pine wood ( wooden comet conspiracy ? ), that is roughly in line with previous comet estimates. That would mean that comets are not rocky, iron rich asteroids, neither are they wispy "cigarette ash" clouds of dust. We know that comets contain large amounts of silicate dust and large amounts of water ice. The bulk density would suggest that there are also empty spaces in the comet although we don't yet know if they are the gaps between dust grains or larger pockets and hollows, or both. The VIRTIS and MIRO instruments have returned some interesting results. VIRTIS can measure the surface temperature and MIRO can see for several tens of cm below the surface. What ESA has found is that large areas of the surface of 67P seem to be blanketed in a high porosity / low thermal inertia material. This could maybe be described as dust ( cometary regolith ), that would seem to be consistent with what OSIRIS is seeing. In other places ( the neck ) there is a lower temperature, higher thermal inertia material, which may be a dust/ice frozen mixture, maybe that's what these cliffs are. http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2014/08/comet_on_7_august_b/14721278-1-eng-GB/Comet_on_7_August_b.jpg In terms of landing in dust, or being covered in dust, Philae has two different battery systems that will keep the lander going long enough to complete the primary science mission, but if it is going to survive for weeks on the surface it will need to draw power from its solar arrays. I don't know how much science it can do if it disappears up to its aerial in dust ! You are also correct to point out that Philae may land on an icy patch that sublimates away causing problems too. I think that was mentioned in the landing site selection process. http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_Landing_site_search_narrows From 25 minutes on this video [youtube]http://www.youtube.com/watch?v=ELbEG1xPX9s[/youtube] http://www.youtube.com/watch?v=ELbEG1xPX9s [quote:TheWatcher-Anonymous Hero:MV8yNTk4OTk2XzQ2MTM1MzY5XzYwQTgzQ0Y2] Incidentally...is there a camera onboard the lander?? [/quote] Yes, there is the ROLIS camera which points downward and will be imaging the comet as Philae approaches its landing site and "stereo panoramic images of areas sampled by other instruments." ( but just the area under and adacent to Philae I believe ) There are also 6 small CIVA cameras that will provide a panoramic view of Philae's landing site. [youtube]http://www.youtube.com/watch?v=YoqokoZkviM[/youtube] http://www.youtube.com/watch?v=YoqokoZkviM K I will have a go at estimating the landing velocity and post it here. [/quote] It will be interesting to see what is discovered about the physical properties of the comet. Perhaps one of the better explanations of what cometary surfaces may be like that I've come across was along this line: If you live in a snowy area a comet may be similar to the snowbank along the side of the road after there's been a long spell of clear weather. The snow bank has gained a black crust on its surface from the melting/evaporating snow leaving behind the sand/ashes which were spread by the sanding trucks. The only difference is that comets are thought to generally have a majority of dust/sand/gravel and a lot of empty air space in the snowy ices that make up the rest. Also, comets may have an organic tar-like residue from the small %age of organics they contain. It should be interesting to learn what Rosetta discovers. Have fun. R. kOOks lie. &c., &c. [/quote]
Original Message
I want to use this thread to highlight news from the Rosetta comet mission.
Ten years ago the European Space Agency ( ESA ) launched the Rosetta comet chaser to rendezvous with comet 67P, go into orbit around it and land a probe on its surface.
120 Icy Patches - by last September
Thread: Rosetta Comet Orbiter -** 120 Icy Patches ** Philae Phones Home ** Ceres Fly Over Video ** New Coma Discovery ** Picture MOTHER LODE ! (Page 69)
thanks FBVA
Philae Phones Home
Great news, thanks F-BVFA
Thread: Rosetta Comet Orbiter -** 120 Icy Patches ** Philae Phones Home ** Ceres Fly Over Video ** New Coma Discovery ** Picture MOTHER LODE ! (Page 68)
Ceres fly over video
Thread: Rosetta Comet Orbiter -** 120 Icy Patches ** Philae Phones Home ** Ceres Fly Over Video ** New Coma Discovery ** Picture MOTHER LODE ! (Page 67)
New Coma Discovery
Thread: Rosetta Comet Orbiter -** 120 Icy Patches ** Philae Phones Home ** Ceres Fly Over Video ** New Coma Discovery ** Picture MOTHER LODE ! (Page 67)
Pictures MOTHER LODE !
- There are
hundreds
thousands of images from Rosetta, this post will always point to the most recent NAVCAM or OSIRIS picture. Updated several times per week. ( Thanks F-BVFA )
Thread: Rosetta Comet Orbiter -** 120 Icy Patches ** Philae Phones Home ** Ceres Fly Over Video ** New Coma Discovery ** Picture MOTHER LODE ! (Page 67)
Ceres Spot Shot
Thread: Rosetta Comet Orbiter -** 120 Icy Patches ** Philae Phones Home ** Ceres Fly Over Video ** New Coma Discovery ** Picture MOTHER LODE ! (Page 66)
Potato
Thread: Rosetta Comet Orbiter -** 120 Icy Patches ** Philae Phones Home ** Ceres Fly Over Video ** New Coma Discovery ** Picture MOTHER LODE ! (Page 66)
When the Rosetta mission is complete we will know so much more about comets, their composition and formation. Comets have been a cause of fear and fascination throughout human history, within the next few months many long standing mysteries will be solved.
K
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