MESSENGER News Thread, news, updates and discussion |
MESSENGER News Thread, news, updates and discussion |
Dec 24 2014, 04:59 PM
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#466
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Senior Member Group: Members Posts: 1585 Joined: 14-October 05 From: Vermont Member No.: 530 |
... by using the helium pressurant for thrust after exhausting all its propellant. Which is neat.
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Dec 24 2014, 09:44 PM
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#467
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Merciless Robot Group: Admin Posts: 8784 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Very innovative. I wonder if this will enable them to determine precisely when the propellant is completely exhausted, presumably by a drop in acceleration during a maneuver. Great data for reality-checking spacecraft fuel quantity models & assumptions.
-------------------- 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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Jan 22 2015, 04:37 AM
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#468
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Senior Member Group: Members Posts: 2090 Joined: 13-February 10 From: Ontario Member No.: 5221 |
They've done it again:
http://messenger.jhuapl.edu/news_room/details.php?id=271 One more will be done on March 18th (the fourth Earth anniversary of MOI)! |
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Mar 13 2015, 06:09 PM
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#469
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Member Group: Members Posts: 241 Joined: 16-May 06 From: Geneva, Switzerland Member No.: 773 |
"Two new papers from members of the MESSENGER Science Team provide global-scale maps of Mercury's surface chemistry that reveal previously unrecognized geochemical terranes -- large regions that have compositions distinct from their surroundings. The presence of these large terranes has important implications for the history of the planet."
http://www.sciencedaily.com/releases/2015/...50313110434.htm Regards, Marc |
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Mar 17 2015, 12:01 AM
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#470
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Senior Member Group: Members Posts: 2090 Joined: 13-February 10 From: Ontario Member No.: 5221 |
Press Release from LPSC: http://messenger.jhuapl.edu/news_room/details.php?id=274
And a load of media: http://messenger.jhuapl.edu/news_room/presscon13_multi.html |
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Mar 20 2015, 07:50 AM
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#471
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Senior Member Group: Members Posts: 2090 Joined: 13-February 10 From: Ontario Member No.: 5221 |
The first in the final series of TCMs is complete, with some unprecedented science about to be done (like Cassini's proximal orbits).
http://messenger.jhuapl.edu/news_room/details.php?id=276 Great to see every last opportunity being squeezed out; it's going to be a long time until BepiColombo shows up. |
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Mar 25 2015, 12:39 PM
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#472
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Member Group: Members Posts: 102 Joined: 8-August 12 Member No.: 6511 |
Great to see every last opportunity being squeezed out; it's going to be a long time until BepiColombo shows up. BepiColombo's launch date seems to have slipped by about 16 months, from August 2015 to 'early 2017', over the last few years. They're still claiming a January 2024 arrival date on the ESA home page, but I'm not sure if that's realistic. "Ten years, give or take, if all goes well" seems like a reasonable estimate right now. So, yes, let's delight in this last surge of data! The investigation into Mercury's paleomagnetism is particularly interesting. -- Meanwhile, a question. At these low periapses, MESSENGER is zooming along pretty fast. I recall there was some discussion that blurring could be an issue. Is it still, or was that resolved? Doug M. |
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Mar 25 2015, 02:26 PM
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#473
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Senior Member Group: Members Posts: 2090 Joined: 13-February 10 From: Ontario Member No.: 5221 |
The press releases look as sharp as ever, so I would assume so.
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Mar 25 2015, 03:12 PM
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#474
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Interplanetary Dumpster Diver Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
I wonder how low it will go before impact. I have dreams of it nearly skimming the surface (even if images are smeared) on a final orbit before the end. Unlikely, but cool if it happened.
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Mar 25 2015, 03:32 PM
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#475
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Founder Group: Chairman Posts: 14433 Joined: 8-February 04 Member No.: 1 |
Based on the trajectory data we've been given for Eyes on the Solar System.... single digit km's in altitude - 5km or so.
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Mar 25 2015, 03:33 PM
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#476
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Member Group: Members Posts: 102 Joined: 8-August 12 Member No.: 6511 |
Press Release from LPSC: http://messenger.jhuapl.edu/news_room/details.php?id=274 Coming a bit late, but this caught my eye: QUOTE "MESSENGER's low-altitude campaign has enabled imaging of the polar deposits in the permanently shadowed floors of Mercury's near-polar craters at higher resolutions than ever previously obtained, says Nancy Chabot, the Instrument Scientist for MESSENGER's Mercury Dual Imaging System (MDIS) and a planetary scientist with APL. "Acquired with the broadband filter of MDIS, low-altitude images show that the deposits have sharp, well-defined boundaries and are not disrupted by small, young impact craters," says Chabot. "These characteristics indicate that the deposits are geologically young. This inference points either to delivery of volatiles to Mercury in the geologically recent past or to an ongoing process that restores the deposits and maintains the sharp boundaries." So, not only does Mercury have polar ice deposits, but they seem to be geologically young? (Do we know how that compares to the Moon? We don't, right?) And that throwaway "ongoing process" comment... Doug M. |
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Mar 25 2015, 04:01 PM
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#477
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Solar System Cartographer Group: Members Posts: 10186 Joined: 5-April 05 From: Canada Member No.: 227 |
This specific observation, of ice patches (in fact seen not just in this crater but in several others) with distinct albedo boundaries and sharp edges, has not been repeated on the Moon, where imaging doesn't seem to show the same type of surface deposit. It's assumed that on the moon the volatiles are more mixed into the surface. In either case, though, the detected volatiles must be young, probably actively replaced, to counteract the effects of micrometeorite erosion. The ongoing process might be cometary impacts (episodic but ongoing), or solar wind implantation in the regolith followed by redistribution, or loss of interior volatiles, maybe associated with those weird hollows.
Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Mar 25 2015, 05:17 PM
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#478
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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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Mar 25 2015, 05:31 PM
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#479
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Senior Member Group: Members Posts: 2090 Joined: 13-February 10 From: Ontario Member No.: 5221 |
Meanwhile, 4,000 orbits completed...
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Mar 25 2015, 07:52 PM
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#480
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Member Group: Members Posts: 102 Joined: 8-August 12 Member No.: 6511 |
This specific observation, of ice patches (in fact seen not just in this crater but in several others) with distinct albedo boundaries and sharp edges, has not been repeated on the Moon, where imaging doesn't seem to show the same type of surface deposit. It's assumed that on the moon the volatiles are more mixed into the surface. In either case, though, the detected volatiles must be young, probably actively replaced, to counteract the effects of micrometeorite erosion. The ongoing process might be cometary impacts (episodic but ongoing), or solar wind implantation in the regolith followed by redistribution, or loss of interior volatiles, maybe associated with those weird hollows. Hadn't thought of solar wind implantation, which of course would be an order of magnitude stronger on Mercury. Loss of interior volatiles would be interesting too -- there's evidence for at least occasional small-scale recent-ish volcanic activity on Mercury. And we know Mercury had pyroclastic eruptions, which hint at significant levels of volatiles in the mantle. (IIUC, that's been a head-scratcher, because the favored models for Mercury's formation and evolution predicted volatile depletion.) Also, if I'm reading the paper abstracts right, it looks like there's a second line of support for the ice being geologically young: apparently there are craters that should be too small and/or too far south to hold ice over gigayear time scales, but that nonetheless do seem to hold ice. Doug M. |
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