MSL scientific results |
MSL scientific results |
May 30 2013, 12:45 PM
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#1
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Member Group: Members Posts: 237 Joined: 22-December 07 From: Alice Springs, N.T. Australia Member No.: 3989 |
Been busy with other things for a while, so it's nice to be back and see all the photo imaging work on the site going from strength to strength
I think a lot of you guys would really enjoy "Curiosity On Mars:First Results" 3 part x approx 2 hr presentations at the EuroGeosciences Union General Assembly published on the EGU Channel on YouTube on May16th. Plenty of good listening for the weekend! Although I enjoy the NASA press briefings, it's great to hear key mission scientists talking full-on to their peers. The talks travel along at a nice fast thought provoking pace! http://www.youtube.com/watch?v=hPbbhfGg0nc Admin: Moved post from 'First Drill' thread. |
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May 30 2013, 06:06 PM
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#2
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Senior Member Group: Members Posts: 1729 Joined: 3-August 06 From: 43° 35' 53" N 1° 26' 35" E Member No.: 1004 |
at long last, the first two peer-reviewed papers on Curiosity's scientific results!
Martian Fluvial Conglomerates at Gale Crater Measurements of Energetic Particle Radiation in Transit to Mars on the Mars Science Laboratory |
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May 31 2013, 07:43 AM
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#3
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Merciless Robot Group: Admin Posts: 8783 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
0.66 Sv +/- 0.12...ouch. Not good.
-------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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May 31 2013, 10:53 PM
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#4
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Member Group: Members Posts: 646 Joined: 23-December 05 From: Forest of Dean Member No.: 617 |
A story by Jonathon Amos on the BBC news site about the Fluvial Conglomerates paper, with a great interview with Sanjeev Gupta:
http://www.bbc.co.uk/news/science-environment-22708902 -------------------- --
Viva software libre! |
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Jun 2 2013, 12:58 AM
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#5
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Newbie Group: Members Posts: 7 Joined: 21-August 12 Member No.: 6598 |
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Jun 2 2013, 01:36 AM
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#6
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Senior Member Group: Members Posts: 3419 Joined: 9-February 04 From: Minneapolis, MN, USA Member No.: 15 |
MSL's cruise phase took place as the Sun was ramping up to an activity peak in its 11-year cycle. And as I recall, we've seen a somewhat unusually active ramp-up this time around. Perhaps radiation-sensitive payloads may have to take advantage of transfer orbit windows that occur during quiet sun periods?
-the other Doug -------------------- “The trouble ain't that there is too many fools, but that the lightning ain't distributed right.” -Mark Twain
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Jun 2 2013, 03:14 AM
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#7
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Senior Member Group: Members Posts: 2504 Joined: 13-September 05 Member No.: 497 |
Perhaps radiation-sensitive payloads may have to take advantage of transfer orbit windows that occur during quiet sun periods? The paper says that only about 5% of the total dose MSL saw in cruise was from solar events, the rest being from galactic cosmic rays. GCR dose rate is thought to be weakly anticorrelated with the solar cycle. They do point out that "the SEP contribution could conceivably be many times larger in a different time frame" (i.e., closer to solar max.) -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
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Jun 4 2013, 01:35 AM
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#8
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Member Group: Members Posts: 866 Joined: 15-March 05 From: Santa Cruz, CA Member No.: 196 |
not to get too OT here, but here's some interesting info on the topic and additional flashes of inspiration
"..The computers recover with a reboot; the cameras suffer permanent damage. After about a year, the images they produce look like they are covered with electronic snow.." |
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Jun 4 2013, 09:38 AM
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#9
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Senior Member Group: Members Posts: 2346 Joined: 7-December 12 Member No.: 6780 |
Those flashes are mostly caused by Cerenkov radiation, when charged particles move faster than light moves in the same medium (phase velocity), however slower than vacuum speed of light, of course. (Light moves slower in most media than in vacuum; speed of light is dependend of wavelength in media.)
The main challenge associated with high-energy cosmic rays isn't the Cerenkov radiation, but a cascade of particle-antiparticle pair production resp. (hadronic) showers of secondary particles. Therefore a shielding can multiply the radiation caused by a GCR hit. The resulting question is, how to design a shielding that reduces solar energetic particles (SEP), and doesn't multiply GCR-induced secondary radiation too much. |
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Jun 4 2013, 10:48 AM
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#10
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Senior Member Group: Members Posts: 2346 Joined: 7-December 12 Member No.: 6780 |
... one idea to circumvent this dilemma is a dynamic shielding, because most of SEP radiation occurs in peaks: SEP graphics in JPL Photojournal.
Thin shielding during low SEP activity to avoid secondary particles caused by GCRs; thick shielding during SEP peaks, detected by instruments, or presumed by forecast. That's a transfere of the answer given in the recent telecon 0:47:09 to 0:49:16 to robotic missions. |
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Jul 18 2013, 06:33 PM
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#11
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Senior Member Group: Members Posts: 1729 Joined: 3-August 06 From: 43° 35' 53" N 1° 26' 35" E Member No.: 1004 |
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Sep 7 2013, 11:39 PM
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#12
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Member Group: Members Posts: 311 Joined: 31-August 05 From: Florida & Texas, USA Member No.: 482 |
fyi: The upcoming Geological Society of America's annual meeting has a few sessions dedicated to MSL:
T1. CURIOSITY AT GALE—PAST AND PRESENT ENVIRONMENTS OF MARS LATE JURASSIC ROCKS OF THE COLORADO PLATEAU AS DEPOSITIONAL AND DIAGENETIC ANALOGS TO GALE CRATER, MARS There's also a session on Mercury, Icy Worlds, Lunar Water, and comparison of Saharan and Mars dunes. |
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Sep 14 2013, 08:20 PM
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#13
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Junior Member Group: Members Posts: 94 Joined: 11-August 12 Member No.: 6536 |
fyi: The upcoming Geological Society of America's annual meeting has a few sessions dedicated to MSL: T1. CURIOSITY AT GALE—PAST AND PRESENT ENVIRONMENTS OF MARS I skimmed through the abstracts. Here are some quotes. * "fluvio-lacustrine sedimentary rocks (showing some signs of volcanic influence), known as Yellowknife Bay formation, which could be as young as middle Hesperian to even early Amazonian." * " a habitable subaqueous sedimentary environment that persisted from 100’s yrs to 10’s Kyrs. " * " influence of at least two generations of fluids." * "Curiosity has observed abundant evidence of geologically recent surface modification at the Gale crater landing site" * "The flagstone-type fracture pattern, mudstone lithology, presence of swelling clay, and occurrence in a dominantly sedimentary sequence suggest that the polygonal fracture pattern of the Glenelg Regionare formed by desiccation in a drying playa...A possible change in climate resulted in drying of the lake, exposure of mudstones, and formation of desiccation cracks. " * "ET-THEN: A POSSIBLE MARTIAN MAGMA?" * " these data suggest late occurring, local alluvial activity on some fans...the timing of possible late alluvial activity in Gale correlates with alluvial activity in Margaritifer Terra hypothesized to result from melting snow...water would have drained downslope and could have contributed to development of late diagenetic features observed by Curiosity in the rocks at Yellowknife Bay." * "The Yellowknife Bay formation has been split into four members (from base to top): the Sheepbed, Gillespie Lake, Point Lake, and Shaler members. The clay-bearing mudstones of the basal Sheepbed member suggest suspension settling in a distal alluvial or proximal lacustrine setting. A sharp contact traceable in orbital images for hundreds of meters separates the Sheepbed member from the Gillespie Lake member. The Gillespie Lake member consists of sheet-like beds of poorly sorted medium- to coarse-grained sandstone. The lateral continuity of these beds and the lack of channel bodies in the Gillespie Lake member indicate deposition in distal fan lobes. Overlying the Gillespie Lake member is the Point Lake member, characterized primarily by the presence of centimeter-scale vugs. Both volcanic and sedimentary interpretations are being considered for this enigmatic member. The overlying Shaler member consists of coarse-grained trough cross-bedded sandstone and pebble beds and recessive finer-grained intervals consistent with a fluvial environment dominated by bedload and suspended load transport. A set of diagenetic features observed throughout the Yellowknife Bay section suggests a complex aqueous history involving multiple phases of alteration. " * "they also contain late diagenetic calcium-sulfate filled fractures that relate to their burial history... hydraulic fractures in YB mudstones attest to substantial burial and vertical movement of evolved brines from underlying or laterally adjacent strata." |
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Sep 15 2013, 01:47 AM
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#14
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Senior Member Group: Members Posts: 2228 Joined: 1-December 04 From: Marble Falls, Texas, USA Member No.: 116 |
Thanks for the nice summary.
-------------------- ...Tom
I'm not a Space Fan, I'm a Space Exploration Enthusiast. |
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Sep 15 2013, 11:25 AM
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#15
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Junior Member Group: Members Posts: 59 Joined: 12-November 09 Member No.: 5039 |
0.66 Sv +/- 0.12...ouch. Not good. According to en.wikipedia.org/wiki/Background_radiation, average exposure in USA is 0.006 Sv/yr. There are several inhabited places on Earth with ~100 times more natural background - making 0.66 Sv/yr not as "ouch" as it looks at the first glance. |
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