Rosetta/Philae spacecraft success

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jsmaje
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Rosetta/Philae spacecraft success

Post by jsmaje »

Hi everyone,

I'm sure you'll be aware of the recent successful rendezvous and continuing close orbit (within a few kilometres) of the ESA ‘Rosetta’ spacecraft after a 10 year flight to Comet 67P/Churyumov-Gerasimenko while it approaches perihelion round the sun next year. Currently about 300 million km from the sun, just within the orbit of Jupiter, it will hopefully continue to accompany and analyse the comet's properties, including its growing 'activity' as the volatiles are blown off in its cometary tail.

More astonishing is that its small partner lander ‘Philae’ successfully separated last week from Rosetta and reached the 2.5-km-wide comet's surface, despite bouncing twice due to malfunction of its tethering mechanisms (the gravity of 67P is something like 400,000 times weaker than that of earth).

Despite ending up in a non-optimal shadowed site, all 10 science instruments have already relayed 90+% of their planned experimental data, including a drill into the surface. Amazing!

I was able to watch all live feeds from the various ESA control centres, which were very exciting. And it was wonderful to hear from the very humble and now-elderly male and female Russian astronomers who first identified the tiny comet in 1969.

Sadly, we may now not hear anything more from Philae unless its solar powered batteries are able to recharge as the comet approaches the sun.

My question to the Berkeley team is that given the first of its bouncy landings on the comet Philae suggested the surface to be covered in about 4cm of dark dust (whether there is ice or rocky stuff below is yet to be determined), how much of such dust may only be the product of the comet's previous activity, how much accreted interplanetary dust, and how much potentially interstellar? Do they have any collaboration with ESA in that regard? I'd hope so.

John

Two of the many links:
http://en.wikipedia.org/wiki/67P/Churyu ... erasimenko
http://rosetta.esa.int/
caprarom
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Re: Rosetta/Philae spacecraft success

Post by caprarom »

Thanks for the synopsis and links, John. Good to hear from you.
DanZ
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Re: Rosetta/Philae spacecraft success

Post by DanZ »

jsmaje wrote:My question to the Berkeley team is that given the first of its bouncy landings on the comet Philae suggested the surface to be covered in about 4cm of dark dust (whether there is ice or rocky stuff below is yet to be determined), how much of such dust may only be the product of the comet's previous activity, how much accreted interplanetary dust, and how much potentially interstellar? Do they have any collaboration with ESA in that regard? I'd hope so.
Let me see what the team says - we're meeting on Monday.

BTW, our lab was featured in a local story on Rosetta, but they've pulled the video down - darn!

And SmithES (formerly ERSTRS) would like to remind us all how scientists use to pull this sort of stuff on in the old days, which is just amazing now that you think about it!

Image

Dan
jsmaje
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Re: Rosetta/Philae spacecraft success

Post by jsmaje »

jsmaje wrote:My question to the Berkeley team is that given the first of its bouncy landings on the comet Philae suggested the surface to be covered in about 4cm of dark dust (whether there is ice or rocky stuff below is yet to be determined), how much of such dust may only be the product of the comet's previous activity, how much accreted interplanetary dust, and how much potentially interstellar? Do they have any collaboration with ESA in that regard? I'd hope so.
DanZ wrote:Let me see what the team says - we're meeting on Monday.
That was Dec 6: so what did they say, or did you not manage to pose the question then or since?

And am I right that behind the ladders in Evelyn's lovely photo of 1960 scientists they may have got their sines & cosines the wrong way round?
Oh well, it's all too easy when in a rush to get ones trigs in a twist!

John
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Re: Rosetta/Philae spacecraft success

Post by DanZ »

jsmaje wrote:
jsmaje wrote:My question to the Berkeley team is that given the first of its bouncy landings on the comet Philae suggested the surface to be covered in about 4cm of dark dust (whether there is ice or rocky stuff below is yet to be determined), how much of such dust may only be the product of the comet's previous activity, how much accreted interplanetary dust, and how much potentially interstellar? Do they have any collaboration with ESA in that regard? I'd hope so.
DanZ wrote:Let me see what the team says - we're meeting on Monday.
That was Dec 6: so what did they say, or did you not manage to pose the question then or since?

John
From Dr. Westphal:

It’s an excellent question. The current flux of interplanetary dust or interstellar dust is far too small to have accumulated this much regolith, even over the age of the solar system. In principle, this might be a veneer of fine-grained material that accreted at the last stage of comet building in the dust-rich disk about 4.5 billion years ago, but most would agree that the current surface is much younger than that. But it is a fascinating question — how did this layer originate? Is it stuff from jets falling back onto the surface? Or devolatalized pristine cometary material? Or…? I (Andrew) will be discussing these things with a couple of Rosetta team members at AGU in San Francisco (which just wrapped up this week).
jsmaje
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Re: Rosetta/Philae spacecraft success

Post by jsmaje »

Thanks Dan and Andrew for the above, and I look forward to further news.

Will the Philae data be able to distinguish elemental & isotopic profiles over depth that could reflect origins and timing?
And given the interstellar Stardust results so far, is there any particular chemical signature that you may be looking for in such profiles?

John
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Re: Rosetta/Philae spacecraft success

Post by DanZ »

Whoa, sorry for missing this John - let me see what I can find out!

Dan
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Re: Rosetta/Philae spacecraft success

Post by DanZ »

jsmaje wrote:Will the Philae data be able to distinguish elemental & isotopic profiles over depth that could reflect origins and timing?
And given the interstellar Stardust results so far, is there any particular chemical signature that you may be looking for in such profiles?
John
Here's your answer from Dr. Westphal:

Once more, excellent questions. The short answer is no, but it is possible that the science team will be able to pull a rabbit out of the hat if Philae powers back up when G-C gets close enough to the sun to provide sufficient power. They’re very clever. Philae does not have an instrument onboard that measure isotopic systems that can measure age.

To address the question of recognizing IS dust on the surface of G-C. It is unlikely that there is a significant amount of contemporary IS dust on the surface, for several reasons: the surface is probably continuously eroding during passages in the inner solar system, the fluence even over the age of the solar system is very small, and the high-speed impacts of IS dust would mostly vaporize them and certainly mix any residues strongly with the cometary material.

What we really need is a sample from a comet surface that we can analyze in the laboratory. We’re working on it!
jsmaje
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Re: Rosetta/Philae spacecraft success

Post by jsmaje »

Fantastic news, Philae awakes! It's now getting sufficient sunlight as Comet 67P approaches the sun (as of today ~130 million miles away and nearing the earth-sun distance; live data here).

Loads of gas and dust are now spewing from the comet (observed by the accompanying Rosetta orbiter), so Philae could eventually get ejected from the surface since the comet's gravity is minimal and its surface tethers have failed.
On the other hand, its unplanned bouncing into a rocky crevice could mean it might be fairly secure, and even survive the comet's swing round the sun in a couple of months. What a spectacle that would be and amazing data to be collected!

OK, it's not interstellar dust, but a real close-up on solar system cometary dust - well of one particular little comet anyway.
So, can I ask the team - in what ways might such data complement the cometary dust particle information already obtained from Wild 2 on 'the other side' of the Stardust collector, and to what extent knowledge of these is or isn't relevant to interstellar/galactic dust?

John
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Re: Rosetta/Philae spacecraft success

Post by DanZ »

Thanks for the news John, exciting! I'll ask Dr. Westphal to address your question in this month's telecon, which will be Thursday this week at the usual time. If you can make it in person, please watch for the posting of the recorded session. Cheers! Dan
jsmaje
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Re: Rosetta/Philae spacecraft success

Post by jsmaje »

Thanks Dr Westphal for addressing my questions posed above on the latest telecon.
I'd suspected there could be no certain answers yet, particularly given your comment regarding the size-limitation of the analytic instruments, to which one can add that Rosetta/Philae were launched 10 years ago, having been designed and equipped with the technology of that time.
I can only hope my latest domestic appliances will turn out to be as long-lived and robust!

Here’s some of the latest news:
detection_of_molecular_nitrogen
comet_not_magnetised
ultraviolet_study_reveals_surprises_in_comet_coma

John
caprarom
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Re: Rosetta/Philae spacecraft success

Post by caprarom »

Good stuff, John. Thanks. Mike
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Re: Rosetta/Philae spacecraft success

Post by DanZ »

jsmaje wrote:Thanks Dr Westphal for addressing my questions posed above on the latest telecon. ....John
Thanks for the questions John! Glad to see you're also enjoying getting the "live" answer, even if you're listening to the playback later. By the way, these recordings have now been moved to our main website at http://stardustathome.ssl.berkeley.edu/category/desk/ where they'll be posted from now on. Please let me know asap if you encounter any problems with the playback. The previous links/files are no longer available. Otherwise, enjoy! Dan
jsmaje
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Re: Rosetta/Philae spacecraft success

Post by jsmaje »

And now, multiple bright spots have started appearing on 67P, most likely water ice exposed/melting/sublimating, to my mind similar-looking to those on Ceres (which albeit 3 times further from the sun is larger and maybe has a warmer core):
Water ice detected on comet surface, and Instrument maps comet water.

Also, with luck: Rosetta mission extended (and may eventually be landed on the comet too)!

PS: Dan, no probs with the recordings having been moved to the main website.
And apologies that my main posting interest has shifted to the evolving Rosetta mission, but Stardust does seem somewhat stalled at the moment, as Andrew Westphal has implied regarding no need for further duster recruits while they wait for more tile data to be provided, as well as more sensitive and non-destructive analytic techniques
.

John
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Re: Rosetta/Philae spacecraft success

Post by SmithES »

Hey guys, This is an article downloaded from Discover mag, current issue. I am a subscriber and am permitted to share this article. I loved the comments about the so-called "pyramid," found on Ceres. I'm glad scientists have a sense of humor! Evelyn, ERSTRS, SmithES

Ceres Gets Weirder With More Bright Spots and Unexplained ‘Pyramid’
By Carl Engelking | June 22, 2015 12:34 pm

(Share on email - Discover Magazine, July-August, 2015, issue)

(Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)
If you thought Ceres’ spots were weird, wait until you see its mystifying ‘pyramid.’
Indeed, Ceres has intrigued NASA scientists and worked fringe UFO bloggers into a frenzy since the Dawn spacecraft arrived for a close-up of the dwarf planet in March. Upon arrival, Dawn imaged a cluster of bright spots in a crater; now, a pyramid towering over a flat landscape serves as the latest addition to Ceres’ scrapbook of oddities.
Scientists have plenty of questions about Ceres’ features, but will we get answers? Maybe.
Space Oddity
Right now, Dawn is in its second orbiting phase roughly 2,700 miles above Ceres, which has given us a closer look at the now famous bright spots. We now know there are even more spots than we initially saw in early images.

A closer look at those mysterious bright spots. (Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)
Scientists believe a highly reflective substance — ice or salt are leading contenders — is responsible for the spots, but they are still considering other options (a thriving alien metropolis is probably not one of them). Thankfully, Dawn is equipped with an infrared mapping spectrometer that can identify minerals based on the way they reflect light. As scientists get more images and data from Dawn, they’ll certainly learn more about the composition of those spots.
And That Pyramid
Dawn also photographed a pyramid-shaped landform in its latest crop of photographs. Based on visual evidence, the mountain rises roughly 3 miles into the sky, and it’s smack-dab in the middle of a relatively flat area on Ceres’ surface. This shouldn’t come as too big of a surprise: Ceres bears all the telltale signs ancient, and perhaps present, geologic activity. Ceres has scars on its surface that hint at ancient lava flows, landslides and collapsed structures.
Ceres’ story is only going to get more interesting. Dawn will continue to orbit 2,700 miles above the dwarf planet’s surface until June 30. Then, it will edge even closer, entering orbit at an altitude of 900 miles sometime in August.
When that time comes, it’s safe to say another strange chapter will be added to the book of Ceres.
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