Here is an odd set of boulders, sitting in the the middle of a area of craters, but not part of a crater. Is it one boulder that fractured on landing?

Its awfully nice of them to be providing these nice images with lots of boulder trails for us to ponder.

Yes, this one has alot of boulder tracks. Qualitatively, it is interesting how thin the dust layer is as evident of the difference between the width of some boulders and narrowness of their track. How deep is the soft stuff supposed to be?

http://wms.lroc.asu.edu/lroc_browse/view/M10463421LE

This was released just prior to the Necho one and on the same day. As can be seen it has really nice resolution/contrast tracks visible at the Apollo 14 site. Of course, these were also imaged on a prior pass and discussed, but they still are impressive. The various images I have seen to show these tracks do not do them justice so I magnified them by 2X and used the Geomatica Freeview palette adjustments to improve the contrast.

If you have the luxury to download the actual tifs, it can still be a bother to try to load them and view them. I use PCI Geometica Freeview Version 10.0
http://www.pcigeomatics.com/index.php?opti...7&Itemid=12
It is nice because it is free, can load 1 Gb files easily and has many different kinds of visual enhancement tools which the LROC image browser lacks/ makes it hard to resolve some features.

I zoomed in by a factor of 2 the LRO image to capture my rolling boulder images and presented all images at the same scale (the LRO raw image is 1.46 m/pixel so if my images are viewed at 100%, then every two by two pixels is 1.46 m by 1.46 m). It is somewhat lossy due to jpeg storage economy. So, for my lower left image boulder (the largest), it is 16 by 21 magnified pixels which is 8 by 10.5 standard pixels or 12 m by 15 m.

Yes, some nice ones. Here is what I found.

I thought Apollo sites were selected to reduce landing risk by picking flat, hazard free places.

What is your estimate of frequency of 1 m diameter boulders? 1 per square kilometer? 1 per 100m^2?

Back in the old Lunar Orbiter days they developed alot of theories for why the boulders eventually rolled downhill. I will have to did up the old reports. I recall thermal cycling and impacts of meteors causing tremors factored into it.

My main interest in these is that they permit the deduction of regolith mechanical properties without having to land there. We don't really have any instruments to deduce these mechanical properties remotely. Landers or rovers could of course, but that is way too costly. During the Lunar Orbiter days, they found a slew of these in the very high resolution images (~1-3m/pixel, which only covered a small percentage of the surface) and derived regolith properties in preparation for Apollo landings.

One of the concerns about the regolith is how much variation there is in its properties over the entire surface. Since interest exists for the near polar regions, it would be nice to be assured the properties are the same there as near the equator. Rolling boulders should be distributed fairly equally over the surface and if there aren't many near the poles, that is significant.

Also, looking at these images, I had supposed there would be many more rocks and boulders (which would be especially visible at some of the shallow Sun elevations for the images), but there seems to be many more craters than boulders (~an order of magnitude). Does this make sense?

Although its not possible to see in the LRO image browser, this image has many boulder tracks in it if you download the tiff and adjust the contrast/brightness appropriately.

I have attached a sample.