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Posted by: Bjorn Jonsson Jan 12 2014, 09:35 PM

Rhea has often been regarded as the least interesting of Saturn's big, icy satellites but (to paraphrase famous words) there is no such thing as an uninteresting Saturnian satellite. Below is a mosaic of Rhea's north polar region from 10 clear filter images and parts of two lower resolution images obtained during rev 183 on March 9, 2013. The full resolution images were obtained when Cassini was between 69,000 and 89,000 km from Rhea. Highly accurate ("C-smithed") camera pointing information is available for two of the full resolution source images. This made it fairly simple to use ISIS to determine accurate pointing for all of the images, resulting in a mosaic which is geometrically very accurate.

It's interesting how extremely cratered some solar system bodies can be:

The resolution varies a bit but is ~500 m/pixel in most of the mosaic. As mentioned above, I had to fill a small gap with lower resolution data. And a smaller version with a grid to show where we are on Rhea:


Now Cassini has imaged Rhea's north polar region at higher resolution and under more favorable illumination conditions than Voyager 1 did. It's interesting to compare the Cassini mosaic to the Voyager 1 mosaic which can be seen in http://www.unmannedspaceflight.com/index.php?showtopic=5606. Some of the terrain in the Cassini mosaic was also imaged by Voyager 1.

Posted by: nprev Jan 12 2014, 11:27 PM

Ridiculously beautiful as always, Bjorn.

Re cratering: There seems to be a spectrum of same here for icy moons in particular that depends on a number of factors. Sure doesn't look like Rhea ever experienced a resurfacing event since at least the LHB, and the crater distribution doesn't seem to suggest that the rings once extended farther than they do now.

Hard to do analogues with anywhere else in the Solar System, though. All the gas/ice giants have unique dynamical situations to consider with respect to their systems of moons that modify any possible hypotheses more than enough to prevent generic principle formulation.

Posted by: MichaelPoole Nov 30 2017, 03:51 PM

Has this extremely high resolution picture of Rhea been posted here before?
https://photojournal.jpl.nasa.gov/jpeg/PIA19057.jpg

Lossless version: https://photojournal.jpl.nasa.gov/tiff/PIA19057.tif

Not boring one bit. Zooming in, that texture is amazing, I feel like I wanna touch it. It is so detailed. Is there a true color version of it/can it be made from the false color picture?