A Close Look at Saturn's Sponge Moon

By Nancy Atkinson - August 26, 2011 at 9:23 PM UTC | Planetary Science
hyperion-1.jpg

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It might be one of the weirdest-looking moons in the solar system: Saturn's moon Hyperion looks like a giant sponge. Additionally, its eccentric orbit makes it subject to gravitational forces from Saturn, so it is just tumbling along, almost out of control. Just yesterday, August 25, 2011, the Cassini spacecraft made a relatively close flyby of Hyperion (24,000 km 15,000 miles away) and took some amazing images.

"Hyperion is a small moon ... just 168 miles across (270 kilometers)... orbiting between Titan and Iapetus," said Carolyn Porco in an email. Porco is the Cassini imaging team lead. "It has an irregular shape and surface appearance, and it rotates chaotically as it tumbles along in orbit, making it impossible to say just exactly what terrain we would image during this flyby."

See some more of the shots below:

[caption id="attachment_88477" align="aligncenter" width="580" caption="Side view taken by NASA's Cassini spacecraft of Saturn's moon Hyperion. Image credit: NASA/JPL-Caltech/Space Science Institute "]

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Scientists say this flyby's closeness has likely allowed Cassini's cameras to map new territory. At the very least, it will help scientists improve color measurements of the moon. It will also help them determine how the moon's brightness changes as lighting and viewing conditions change, which can provide insight into the texture of the surface. The color measurements provide additional information about different materials on the moon's deeply pitted surface.

[caption id="attachment_88478" align="aligncenter" width="580" caption="A darker view of Hyperion. Credit: NASA/JPL-Caltech/Space Science Institute"]

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[caption id="attachment_88475" align="aligncenter" width="580" caption="NASA's Cassini spacecraft obtained this unprocessed image of Saturn's moon Hyperion on Aug. 25, 2011. Image credit: NASA/JPL-Caltech/Space Science Institute "]

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The next closest pass of Hyperion is coming up again soon: Sept. 16, 2011, when it passes the tumbling moon at a distance of about 36,000 miles (58,000 kilometers).

See more raw images at the

CICLOPS website.

Nancy Atkinson

Nancy Atkinson

Nancy Atkinson is a space journalist and author with a passion for telling the stories of people involved in space exploration and astronomy. She is currently retired from daily writing, but worked at Universe Today for 20 years as a writer and editor. She also contributed articles to The Planetary Society, Ad Astra (National Space Society), New Scientist and many other online outlets.

Her 2019 book, "Eight Years to the Moon: The History of the Apollo Missions,” shares the untold stories of engineers and scientists who worked behind the scenes to make the Apollo program so successful, despite the daunting odds against it. Her first book “Incredible Stories From Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos” (2016) tells the stories of 37 scientists and engineers that work on several current NASA robotic missions to explore the solar system and beyond.

Nancy is also a NASA/JPL Solar System Ambassador, and through this program, she has the opportunity to share her passion of space and astronomy with children and adults through presentations and programs. Nancy's personal website is nancyatkinson.com