Highlighting Rhea’s Subtle Colors – New Cassini Images of Saturn’s Moon

Color-composite of Rhea (NASA/JPL/SSI/J. Major)

This is a color composite image of Rhea (pronounced REE-ah) I made from raw images acquired by the Cassini spacecraft on March 9, 2013, during its most recent — and final — close pass of the moon. The visible-light colors of Rhea’s frozen surface have been oversaturated to make them more apparent… even so, it’s still a very monochromatic place.

The Color of Rhea

Color-composite of Rhea, Saturn's second-largest moon.

If someone were to ask you today what the most heavily-cratered world in the Solar System is, you can’t go wrong with saying “why, Rhea of course!”

(I don’t know why someone would ask you that, but if anyone does you can now consider yourself well-prepared.)

Rugged Rhea

IR/G/UV color-composite of Rhea

Here’s a color-composite image of Rhea, made from raw images acquired by Cassini during a flyby on March 10, 2012. The color is derived from images taken in infrared, green and ultraviolet light.

Ride Along With Rhea

Animation made from raw Cassini image data acquired April 25, 2011

Assembled from 29 raw images taken by the Cassini orbiter on Monday, April 25, this animation brings us along an orbital ride with Rhea as it crosses Saturn’s nighttime face, the planet’s shadow cast across the ringplane. Sister moons Dione and Tethys travel the opposite lane in the background, eventually appearing to sink into Saturn’s atmosphere.

Rhea and the Rings

This is one of those sublime photos from Cassini that just make me smile. Taken on March 24, this raw image shows Rhea, Saturn’s second-largest moon, suspended in orbit in front of the twilight side of Saturn, its rings reduced to a thin ribbon of bands at this viewing angle. The width of the rings is hinted at by their shadows falling onto the southern half of the planet…and little Epimetheus passes by in the background between them and Rhea. Simply beautiful!

Cassini was over 772,000 miles from Rhea when it took this picture.

UPDATE: Check out my color version of this image here.

Image: NASA/JPL/SSI.

Enceladus and Rhea

Rhea passes behind Enceladus: click to play

In another stately pas de deux as seen from the point of view of the Cassini spacecraft, moons Rhea and Enceladus slip past each other in their eternal travels around Saturn. This animation is made up of 20 raw images from Cassini, taken on November 15, level-adjusted and rotated 90º clockwise.

Enceladus is about to get another close look as well….on Saturday, November 21, Cassini will perform its eighth flyby of the moon, making a visual reconnaissance of the south pole and its fractured terrain where the moon’s icy jets eminate from. It will then turn its attention to Rhea…I’m looking forward to some great images from this upcoming flyby! Stay tuned.

Edited 11/18: a similar animation by Emily Lakdawalla of The Planetary Society says the larger moon above is Rhea. I believe her expertise over my uneducated guess. I always have a hard time telling those two apart, especially at higher phase angles.

Raw images: NASA/JPL/SSI. Animation: J. Major.

A Rhea View

Here’s an amazingly detailed view of the extensively cratered surface of Rhea, Saturn’s second-largest moon, taken during a particularly close encounter by Cassini on October 13, 2009.

About 950 miles wide Rhea is less than a third the size of Titan, Saturn’s largest moon. Unlike Titan, Rhea has no atmosphere at all to speak of and is composed mostly of water ice, which behaves like solid rock in the frigid temperatures found at those distances from the sun.

Raw image: NASA/JPL/Space Science Institute