MESSENGER News Thread, news, updates and discussion |
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MESSENGER News Thread, news, updates and discussion |
 Mar 26 2015, 12:21 AM
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#481
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 Interplanetary Dumpster Diver  Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33  |
QUOTE (djellison @ Mar 25 2015, 03:32 PM)  Based on the trajectory data we've been given for Eyes on the Solar System.... single digit km's in altitude - 5km or so. Yeah, I just hope imaging succeeds. -------------------- |
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Mar 26 2015, 06:33 PM
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#482
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 Administrator Group: Admin Posts: 5172 Joined: 4-August 05 From: Pasadena, CA, USA, Earth Member No.: 454 |
Sean Solomon told me that there is motion blur at the lowest altitudes. It's a lot like Dawn: the super-low altitudes are especially designed for the neutron spectrometer. (And for the magnetometer, which Dawn, sadly, doesn't have.) Of course, MESSENGER's orbit is elliptical, so it spends little time at 5km. They're still imaging. This is one of the highest-resolution images MESSENGER has acquired, and it's clearly worth the effort.
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Mar 26 2015, 07:45 PM
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#483
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Junior Member Group: Members Posts: 78 Joined: 20-September 14 Member No.: 7261 |
Am I correct in that MESSENGER currently has the lowest periapsis of any orbiter - not intending to land/crash on that orbit - ever in relation to the size of the body it's orbiting?
The lowest otherwise I can think of is LRO with elliptic orbit and 30 km perilune. Apollo 15 doesn't count, it went back to a higher orbit after LM separation. For small bodies Rosetta at 8 km distance still has Messenger beat in absolute value, but not in relation to the orbited body. |
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Mar 26 2015, 08:04 PM
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#484
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Administrator Group: Admin Posts: 5172 Joined: 4-August 05 From: Pasadena, CA, USA, Earth Member No.: 454 |
GRAIL got as low over Orientale before it crashed; I think I've heard Maria Zuber say they flew within 2000 meters of the rim, intentionally, repeatedly.
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Mar 27 2015, 07:23 PM
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#485
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 Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
QUOTE (Phil Stooke @ Mar 25 2015, 09:01 AM) The ongoing process might be cometary impacts (episodic but ongoing), or solar wind implantation in the regolith... A thought: Mercury has a magnetic field, but very little atmosphere, which makes it relatively unique. And, as noted, it encounters much stronger solar wind than any other body. Because it has a magnetic field, charged particles ought to be concentrated at the poles, and hitting bedrock, as opposed to making aurora. Which is all to say, Mercury's poles could have an enormously higher solar wind flux than anywhere else in the solar system: Maybe more than two orders of magnitude stronger? |
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Apr 9 2015, 09:10 PM
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#486
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Senior Member Group: Members Posts: 1580 Joined: 14-October 05 From: Vermont Member No.: 530 |
Messenger is now out of hydrazine and using helium exclusively.
http://messenger.jhuapl.edu/news_room/details.php?id=280 |
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Apr 20 2015, 04:21 PM
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#487
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 Senior Member Group: Members Posts: 2074 Joined: 13-February 10 From: Ontario Member No.: 5221 |
Out of solar conjunction, and now the image releases are very new: today's is from the 16th!
http://messenger.jhuapl.edu/gallery/scienc...p;image_id=1589 |
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Apr 25 2015, 02:23 AM
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#488
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Senior Member Group: Members Posts: 2074 Joined: 13-February 10 From: Ontario Member No.: 5221 |
And one from yesterday! 1.1 meters per pixel, wow!
http://messenger.jhuapl.edu/gallery/scienc...p;image_id=1593 |
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Apr 26 2015, 08:56 AM
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#489
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Junior Member Group: Members Posts: 65 Joined: 19-November 14 From: Milan, Italy Member No.: 7340 |
QUOTE (Explorer1 @ Apr 25 2015, 04:23 AM) And one from yesterday! 1.1 meters per pixel, wow! Is this the highest-resolution photo ever taken of Mercury or did I miss something? |
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Apr 26 2015, 09:26 PM
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#490
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Senior Member Group: Members Posts: 1580 Joined: 14-October 05 From: Vermont Member No.: 530 |
QUOTE (Explorer1 @ Apr 24 2015, 09:23 PM) And one from yesterday! 1.1 meters per pixel, wow! Mercury must be fractal. Soft-edged craters at all scales. |
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Apr 27 2015, 01:14 AM
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#491
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 Merciless Robot Group: Admin Posts: 8783 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
I noticed the soft edges too...very lunar in appearance at this scale. Wonder if that means that micrometeoroid flux is more or less the same in Mercury's region as it is out here.
-------------------- 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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Apr 27 2015, 08:36 AM
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#492
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Member Group: Members Posts: 102 Joined: 8-August 12 Member No.: 6511 |
Emily mentioned that "Sean Solomon told me that there is motion blur at the lowest altitudes". Could those soft edges be caused by that?
Doug M. |
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Apr 27 2015, 10:06 AM
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#493
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Senior Member Group: Members Posts: 2346 Joined: 7-December 12 Member No.: 6780 |
Motion blur would apply to the small craters, as well, in absolute terms.
But small craters look well-resolved. |
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Apr 27 2015, 10:49 AM
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#494
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Forum Contributor Group: Members Posts: 1372 Joined: 8-February 04 From: North East Florida, USA. Member No.: 11 |
QUOTE (pitcapuozzo @ Apr 26 2015, 09:56 AM) Is this the highest-resolution photo ever taken of Mercury or did I miss something? Messenger is flying very low and very fast. It was not really designed to take images in this mode. The image is only 560 meters across. Messenger is taking a few last images before it crashes into Mercury, it has ran out of fuel. |
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Apr 27 2015, 11:30 AM
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#495
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 Senior Member Group: Members Posts: 3648 Joined: 1-October 05 From: Croatia Member No.: 523 |
There doesn't appear to be significant motion blur in that image - it was obviously binned 2x2 with a likely very short exposure as the readout smear is noticeable in the bottom, and it's a relatively bigger effect the shorter the exposure.
Crater soft edges look reminiscent of lunar craters at the same scale - regolith and subsequent weathering? -------------------- |
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