That's a very interesting point. In effect it's what the Apollo 16 astronauts looked for at Shadow Rock, south of North Ray crater, but that was really not a very good candidate. One objection to the idea of volatiles collecting in a crevice in a rock pile is that they may not last long enough. Small impacts probably break up boulders often enough that the crevices change or disappear, or get filled with ejecta, on too short time scales. Still, it's certainly possible. Makes me wonder about the much-talked-about idea of lava tubes as habitats - would they contain ice patches too?

Phil

I'd think so... in fact seeing as how easy it would be to make a lunar cold trap there should be a lot of them in various forms. It'd just be a case of picking the oldest and least disturbed. An ancient cold trap that got hit by a meteorite would probably leave a fingerprint of volatile species in the lunar exosphere.

here is a context image for the Tsiolkovskiy image...I am not sure were to lay the strip, but I see now why there are boulder tracks and collections of boulders

Click to view attachment

http://lroc.sese.asu.edu/news/?archives/10...-barn-door.html

New featured image. Measuring jitter.

Surely...the jitter-bug

Those LROC guys just don't get in enough dance routines in between uploading images, I'm thinking

John

A new image: Timocharis crater.
http://wms.lroc.asu.edu/lroc_browse/view/M102242995R

New data from all LRO instruments are expected to be released on Thursday... should be good!

Phil

Really? Awesome. Guess I'll have something productive to do during our Thursday morning staff meeting

--Emily

A nice new image of part of Shackleton at LROC today.

Phil

COOL. Thanks for the heads up. I love the "The full NAC mosaic reveals a shelf on the southeast flank of the crater that is more than two kilometers across and perfectly suitable for a future landing."

--Emily

... though I'm not sure what "southeast" means in this context.

Phil

Click to view attachment

I think this is the area they are talking about (toward the bottom of the image). As Phil points out, directions are kind of useless near the Poles. But the upper part of the image is better illuminated due to the downward slope/Sun direction...so its the crater wall... not a good spot to land. So the more flat rim portion at the bottom of the image is a more likely spot to land, although it may not be near the best site to place the base (if we base it on having the shortest annual night period). I still need to get oriented on the image.

Didn't find any rolling boulders yet!!! Drat!!

Earth must be generally towards the bottom of the image, from the location of the pole.

Phil

The Lunar Reconnaissance Orbiter Press Conference.
In case anybody missed it (like me) - an ASF video file can be downloaded at -

116 MB ASF file
http://www.space-multimedia.nl.eu.org/
or
http://bit.ly/Ahe4Y

Also replay tomorrow on NASA TV
12:00 GMT
September 18, Friday
8 a.m. Eastern Time - Replay Lunar Reconnaissance Orbiter Press Conference - GSFC (Public and Media Channels)

Jack

Comparing the MiniRF mosaic and the LOLA topo map... the big massifs in the LOLA map, the red areas (they are South Pole-Aitken basin ring mountains) look unusually dark in the MiniRF. I don't see it as just topographic shading, but can't figure out what it is yet.

Phil

New image of Mare Insularum is up... now that's what I call a shadow!

Click to view attachment

FULL INLINE QUOTE REMOVED - ADMIN

Anyone trying to download the entire 504 Mb file should note the name is incorrect. It is...
http://lroc.sese.asu.edu/data/pr/tiff/nacl00001431.tif.tif

I'am still waiting on new images with a high resolution in low orbit
Last relaesed image 25-aug.

Why must we wait so long for data? In 1969 we have live tv from the moon.
Of is there a direct link too these images?

Patience! They have released plenty of images already. The new ones from half the height will not look very different for most targets. If you check the LRO website, the Operations Journal, you can read this:

"My name is Andrew, and I am currently an undergraduate Industrial, Systems and Operations Engineering student at Arizona State University, where LROC operations are based. At LROC, I am currently employed as the web developer. This means I am the person who is primarily responsible for maintaining, developing and making updates and additions to the LROC website (as well as other websites for associated projects)."

Bearing in mind that they are getting a Niagara of data every day, and the website is updated by a busy student, I think they are doing a great job already. There's just too much downlink to have every image, every day the way MER does it.

Phil

A new image has been posted: a spectacular oblique limb view:
http://wms.lroc.asu.edu/lroc_browse/view/M106797147

"nother LRO image

http://wms.lroc.asu.edu/lroc_browse/view/M104419352R

"The linear rille Rima Ariadaeus is found on the nearside of the Moon, nestled between Mare Tranquillitatis and Mare Vaporum."

Ooohh!! "Apollo 11 Second Look"...

http://wms.lroc.asu.edu/lroc_browse/view/M104362199R

Cool! And still in the commissioning orbit, so the final views will be twice as good.

Phil

So ... what's best for finding the actual site with Stu's Zoomify link?

This is something like 'Where's Waldo' to me

Over on the dedicated LRO/Apollo landing site images thread I posted a link to a pic that will help you find the landing site

Three LROC images have been released in the last week or so.
http://wms.lroc.asu.edu/lroc_browse
Are we getting bored already, or maybe the images are not spectacular enough? Anyway, they are not arousing much response here. Spoiled kids that we are!

I've been downloading and looking at them. But with no boulder tracks, I have little to report.

Also, you gotta agree that your eyes start to cross if you look at the entire image at full resolution (by stepping through it) and that if you have seen alot of craters and a few boulders, its hard to get that excited unless you really are looking for something.

I was hoping for more images near the south pole.

I am excited about the data on this page from the LOLA instrument!
http://svs.gsfc.nasa.gov/vis/a000000/a003600/a003633/

http://lroc.sese.asu.edu/news/?archives/12...he-surface.html

This looks like the first image from the lower orbit to be released. Very high sun, so no shadows but interesting albedo variations.

Phil

Very bright impact ejecta which is natural for fresh craters. Wonder what the spectrometers will tell us about composition

Holy cow! I'm awfully cynical about the moon sometimes (boring old atmosphere-less dry rock with hardly any volcanoes to liven things up), but these are just gorgeous. Who needs shadows?

http://lroc.sese.asu.edu/news/?archives/12...ric-Ejecta.html

You missed this

Asymmetric ejecta

Fabulous collection of rolling and bouncing boulder trails on the latest LROC image...

http://wms.lroc.asu.edu/lroc_browse/view/M107985155LE

Phil

Wow, those are great! The "bouncing boulder" tracks seem to go on pretty far. Does that make sense? The sustained dynamics over such a long distance seem to be unlikely. Yet there they are!

Click to view attachment

Rolling rock alert, James!

http://wms.lroc.asu.edu/lroc_browse/view/M104227032L

Phil

These rolling boulders are interesting. Note how the one I show here (went ~1.2 km on this image) doesn't seem too bothered by a crater but gets a course change by another toward the end. Probably due to alot of energy early in the rolling. This would make a good dynamics analysis to figure out.

What is the maximum distance a boulder could roll or bounce? I haven't seen (or can't remember seeing) that being done.
Click to view attachment

Distance rolled would depend on whether it's travelling under gravity down a slope (maybe after being dislodged by a quake or ground shaking from a nearby impact ), or whether it's an ejecta boulder with sideways kinetic energy addtional to anything deriving from gravity. Thrown stones skipping across a pond come to mind...

You'd need to find evidence of ejecta rolling: perhaps examples of tracks starting on the level, or going substantially up-slope beyond a starting potential energy.

But bear in mind that the moment of inertia for a rolling rock is mainly dependent on its mass (since we need "round" rocks to roll at all, the shape's effect on inertia is less crucial).

The likelihood for a rolling rock to embed itself and stop rolling is partly dependent on the surface material and its ability to support the rock - this naturally relates to the weight of the rock.

So the Moon's clearly a better choice compared to the Earth: mass is the same, weight is not; the surface is largely homogenous: no damp, no vegetation, no atmosphere to help braking.

While it's tempting to think that the longest of these trails are perhaps caused by ejecta hitting the ground at shallow angles - ejecta which already has a roll imparted at launch, that can aid such long track-making - I'm not sure that's necessarily the case. The Moon's just a better place for <ahem> rock and roll.

Andy

From a prior LRO offering (http://wms.lroc.asu.edu/lroc_browse/view/M107985155LE), one of the tracks showed an oblong boulder that somehow bounced a considerable distance (I attach an excerpt at 2X), ~1.5 km.

I assume the boulders are fairly rigid, so what can I infer about the regolith? I remember seeing the inferred regolith characteristics from boulder tracks and they focused mainly on the width/deepness of the track and the mass of the boulder, but nothing regarding implication of bouncing boulders.

We need to get the LOLA data to understand these slopes better and start doing these calculations in earnest.

Click to view attachment

Another rolling boulder...

http://lroc.sese.asu.edu/news/?archives/13...lder-Trail.html

But unlike any lunar image I've ever seen before. LROC is amazing - it's like a whole new moon.

I think slope processes like those on view all over this image are some of the most visually striking things we're seeing in these images.

Phil

That's an interesting one. You can see what look like several older boulder trails as well in the image.

Wonder if we'll get lucky & get some before & after shots of an event. This looks like something that happens relatively frequently!

We even get one seen close by by Apollo 17! Do we know when this one rolled down?

I seem to recall that the huge boulder at Taurus Littrow in that well-known Apollo 17 photo, was thought to be an ejecta block - so was 'flung' rather than rolled into position.

I'm not aware of any statement like that in the literature.

Phil

My earlier speculation on the movement of the Apollo 17 Morth Massif Split Rock and its descent trail was that it has moved as a result of incremental thermal creep, by preferential expansion in the downhill direction of least soil resistance, due to heating in the lunar day. The slope there seems to me not to be steep enough for such an enormous and unevenly shaped boudler to roll (when it was one piece before it split apart).

If this is correct, or at least plausible, we may have 3 methods of boulder transport which leave trails, in decreasing order of speed:

• ejecta bouncing across surfaces
• gravity tumbling/rolling/ sliding
• thermal creep over millennia.

"The slope there seems to me not to be steep enough "

Do you mean the slope at Station 6, where the rock is now? That's where it stopped rolling, not where it started, so we might expect it to be 'not steep enough' to roll.

Phil

I mean my general impression of the immediate part of the slope leading down to the boulder at Station 6, over which the rock rolled or slid, apparently gouging out a deep track or channel. The boulder track is evident as a sort of channel leading towards the boulder from the right side of this pan. The astronauts walked through this channel, as their footprints show.

Station 6 pan, Apollo 17

My admiitedly superficial impression is that the general slope angle is low for a gravity roll, but as you say, it ran out of energy and stopped here, perhaps for that reason. However, the depth of the track is very considerable, and I wonder if such a depth could really have been made by a boulder rolling over the surface - as opposed to my alternative thought that it was a partially embedded boulder moving downhill by creep over long periods of time.

Phil's crop of LRO, Station 6, Apollo 17

I can't find your orginal post of this picture, but the above is a re-post. Looking at it again, I think seeing the track from above does suggest the rolling of an irregular boulder rather than the uniform track width which the "ploughing boulder" might generate.

So I'm coming back to a rolling stone (!).... but still curious as to whether the ploughing boulder pehnomenon, caused by thermal expansion creep, might be seen elsewhere on the moon.

I was curious as to why I remembered reading that the boulder was assumed to have been thrown from a nearby crater, so checked in some of my books. Sure enough, in 'Planetary Geology' (1979 edition Guest, Butterworth, Murray, O'Donnell) the authors assert this most confidently. The fact that the boulder is in two pieces in situ perhaps made this seem the most likely explanation at the time. (i.e it split in two when it re-impacted)
However, having now seen the boulder and associated furrow from LRO, it's clearly rolled or bounced into position.

Jase

Well done for finding that significant reference!

Science is natural selection... the evolution of ideas.

Nice new bouncing boulder...

Click to view attachment