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LROC news and images
Guest_Zvezdichko_*
post Jul 11 2009, 04:55 PM
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Knowing the fact the current resolution is about 1 meter per pixel at least and these rock are larger than a pixel (or even a few pixels), you are right. But they look cool biggrin.gif
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Guest_Zvezdichko_*
post Jul 13 2009, 11:05 PM
Post #77





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OK, on topic:

http://lroc.sese.asu.edu/news/?archives/74...gle-Camera.html

A new WAC image has been published
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jmknapp
post Jul 14 2009, 11:31 PM
Post #78


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Didn't see this recent news item mentioned here:

http://www.spaceflightnow.com/news/n0907/06kaguya/

"Japan's now-finished lunar mission found no water ice"

QUOTE
"However, [Selene imaging] indicates that exposed relatively pure water-ice deposits are lacking on the floor [of Shackleton Crater]," according to the Japanese report. Japanese scientists said in Houston they could not find water ice anywhere else in craters near the Moon's rugged south pole, one of the primary NASA justifications for flying the LCROSS mission.


The LRO press kit mentions two competing theories for why Clementine saw decreased neutron flux at the poles, both involving absorption of same by hydrogen: either in water form, or alternatively hydrogen deposited from solar wind could be more stable and accumulate more due to the cold polar temperatures.



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dvandorn
post Jul 15 2009, 01:14 AM
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I don't think anyone has ever anticipated finding glaciers of white ice just sitting in the bottoms of polar lunar craters. Exposed ice would sublimate quite quickly when exposed to the vacuum.

Instead, I believe the expectation is to find an "icy regolith" layer (something like a permafrost layer) underneath a completely dry layer of regolith. The minute gaps between the grains of the covering regolith cap would be enough for the tiny amount of sublimation that results in the hydrogen signature detected by Clementine and Lunar Prospector.

-the other Doug


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jmknapp
post Jul 15 2009, 02:00 AM
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QUOTE (dvandorn @ Jul 14 2009, 09:14 PM) *
I don't think anyone has ever anticipated finding glaciers of white ice just sitting in the bottoms of polar lunar craters. Exposed ice would sublimate quite quickly when exposed to the vacuum.

Instead, I believe the expectation is to find an "icy regolith" layer (something like a permafrost layer) underneath a completely dry layer of regolith.


When the Lunar Prospector announcement was made the figure of "1% water" or something like that was given, which added up to a lake's worth if the total input is a gazillion tons or whatever. Later it was pointed out that hard concrete has a similar amount of water, so extracting drinking water seemed less plausible. Let's hope the figure is quite a bit above that!

BTW, according to the materials for the LAMP instrument:

QUOTE
The Lunar Reconnaissance Orbiter
(LRO) Lyman-Alpha Mapping Project (LAMP) is a
UV spectrograph designed to address how
water is formed on the moon, transported through the
lunar atmosphere, and deposited in permanently
shaded regions (PSRs). Its main objectives are to 1)
identify exposed water frost in PSRs, 2) characterize
landforms and albedos in PSRs, 3) demonstrate the
feasibility of using natural starlight and sky-glow illumination
for future lunar surface mission applications,
and 4) assay the lunar atmosphere and its variability.

The production and transport of lunar atmosphere
constituents (e.g., H, Ar, and potentially others) will be
investigated by observation of their resonantly scattered
FUV emissions. LAMP albedo maps of PSR
landforms and potential surface water ice will be used
to investigate the intriguing processes that occur
within PSRs. Potential sites of active outgassing such
as the Aristarchus crater and the Ina structure are
targets of special interest for LAMP spectral map
products.


Would that imply that LAMP is only suited for detecting surface ice/frost?



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Guest_Zvezdichko_*
post Jul 22 2009, 10:23 AM
Post #81





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http://lroc.sese.asu.edu/news/?archives/77...Moon-in-3D.html

LROC images in 3D
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glennwsmith
post Jul 23 2009, 03:54 AM
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Yes, Dvandorn, I think the situation on the moon will be similar to what Phoenix found on Mars -- ice (or an ice rich regolith) covered by a relatively thin layer of dry regolith.
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John Moore
post Jul 23 2009, 10:47 AM
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Very nice bit here on the whole LCROSS cruise phase setup -- flight director for LCROSS. Well worth a read.

John
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Phil Stooke
post Jul 29 2009, 03:34 AM
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A couple of nice new LROC images posted on their site in the last couple of days. This is a really nice camera!

Phil


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Phil Stooke
post Jul 29 2009, 01:49 PM
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This is a tiny detail from the upper wall of Burg crater in the latest LROC image. Nice dust streamers - I don't recall anything like this in Apollo or Lunar Orbiter images.

Phil

Attached Image


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nprev
post Jul 30 2009, 04:48 AM
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Hmm. And you of all people would certainly know, Phil.

That's really interesting. If they are in fact dust streamers, what's the sorting mechanism to generate them? It's gotta be a thermal expansion/contraction thing, but nothing obvious springs to mind.


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John Moore
post Jul 30 2009, 10:21 AM
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Yes...hmmm...I wonder would quakes be a contributing factor?

Phil, is it odd that the albedo of these streamers is lower than from where they originated from -- I would have thought the layer of dust that rolled down wouldn't have changed it much?

John
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Phil Stooke
post Jul 30 2009, 11:05 AM
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Particle size and surface texture affect reflectivity as well as albedo. We can't separate those factors yet and say the albedo is different.

Electrostatic effects might move dust while leaving coarser material, allowing it to slide downhill on its own.

Phil


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jmknapp
post Jul 30 2009, 11:29 AM
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How long ago might such a landslide/deposit have taken place? A billion years? Only when the crater formed? Or perhaps more recent?


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Phil Stooke
post Jul 30 2009, 11:54 AM
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I would guess that the large wall slumps defining the crater terraces occurred immediately after crater formation, the small local landslides which form rubbly deposits on the terraces take place sporadically every few million years, and that these dust treamers are formed by gradual, continual (or short timescale episodic, like every year or two) ongoing processes.

There are some nice rolling boulder tracks below this area.

Phil


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