CICLOPS: Cassini Imaging Central Laboratory for OPerationS
Somersaulting Moon

Somersaulting Moon
PIA 12748

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  Cassini captures a view of Saturn's tumbling moon Hyperion.

To learn more about this spongy moon and how it tumbles in its orbit, see PIA06243, PIA07761 and PIA07740.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Nov. 28, 2010. The view was obtained at a distance of approximately 80,000 kilometers (49,000 miles) from Hyperion and at a Sun-Hyperion-spacecraft, or phase, angle of 98 degrees. Image scale is 476 meters (1,561 feet) per pixel.

[Caption updated Oct. 24, 2011.]

The Cassini Solstice Mission is a joint United States and European endeavor. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini Solstice Mission visit, and

Credit: NASA/JPL/Space Science Institute
Released: January 10, 2011 (PIA 12748)
Image/Caption Information

Alliance Member Comments
carolyn (CICLOPS) (Jan 12, 2011 at 7:43 PM):
Mercury and lsludwig: Hyperion looks the way it does -- with surprisingly deep-looking craters -- because it is underdense and on the small side. This means that impactors do more compression than excavation and so penetrate deeper. And the impact ejector may (1) be less abundant because of that, and (2) escape the moon entirely, leaving no ejector blankets. For the full story, read this paper, under the SCIENCE section of this website:
Mercury_3488 (Jan 12, 2011 at 12:39 PM):
Hi lsludwig1,

Yes I agree, Hyperion is very curious. One idea is that the deep fluted craters are due to normal craters being deepened by the dak dusty floors absorbing what little sunlight is out here & 'burning' a deeper hole, giving Hyperion the peculiar sponge like appearance. Also Hyperion is the least dense 'solid' body at only 0.55 Gcm3, just over half that of solid H2O ice, suggesting that Hyperion is an icy rubble pile held together by gravity. Certainly sopme asteroids are like this, main belt asteroid 253 Mathilde certainly so, rather carbonaceous materials rather than ice, the Mars moon Phobos (possibly Deimos too) & the Jupiter moon Amalthea. Phoebe appears coherent as does the main belt asteroid 21 Lutetia, so not all 'small' bodies are rubble piles, but Hyperion almost certainly is. Whether or not Hyperion is a captured comet is open to question, where as Phoebe most certainly is. Shame we cannot get another close pass of Phoebe, but I think we will see Hyperion again with Cassini.

Hi Carolyn,

Do we know when yeaterday's Rhea imagery will be avaliable? Hope Cassini has not gone into safing.

Andrew Brown.
lsludwig1 (Jan 11, 2011 at 4:38 PM):
I've been looking at enlargements of Hyperion images and finally realize what it is that makes it look so different to me from other moons. It reminds me of what a close-up of a lump of slightly eroded coral looks like: the larger crater being the polyp cores. The other imagery is that of worm pumice stone: the larger craters like the surface bubbles. What all three might have in common is a lightness and porosity.

The other oddity is that craters are of three distinct sizes: the obvious large craters; craters about a tenth the size and then very very small craters. And between all of these craters is a very soft surface void of any large craters like it was dusted over with snow. This would imply to me that Hyperion either has been subject to different conditions in space (was it a comet?)or its own unique geology, as Enceladus has its own unique geology.