Tag Archives: Cassini

New, Incredible Closeup Images of Saturn’s Moon Dione

Saturn's Moon Dione
This view from NASA’s Cassini spacecraft looks toward Saturn’s icy moon Dione, with giant Saturn and its rings in the background, just prior to the mission’s final close approach to the moon on August 17, 2015.

Cassini’s Final Breathtaking Close Views of Dione

By NASA
8-20-15

      A pockmarked, icy landscape looms beneath NASA’s Cassini spacecraft in new images of Saturn’s moon Dione taken during the mission’s last close approach to the small, icy world. Two of the new images show the surface of Dione at the best resolution ever.

Cassini passed 295 miles (474 kilometers) above Dione’s surface at 11:33 a.m. PDT (2:33 p.m. EDT) on Aug. 17. This was the fifth close encounter with Dione during Cassini’s long tour at Saturn. The mission’s closest-ever flyby of Dione was in Dec. 2011, at a distance of 60 miles (100 kilometers).

The full set of images released today is available here.

“I am moved, as I know everyone else is, looking at these exquisite images of Dione’s surface and crescent, and knowing that they are the last we will see of this far-off world for a very long time to come,” said Carolyn Porco, Cassini imaging team lead at the Space Science Institute, Boulder, Colorado. “Right down to the last, Cassini has faithfully delivered another extraordinary set of riches. How lucky we have been.”

Raw, unprocessed images from the flyby are available here.

The main scientific focus of this flyby was gravity science, not imaging. This made capturing the images tricky, as Cassini’s camera was not controlling where the spacecraft pointed.

“We had just enough time to snap a few images, giving us nice, high resolution looks at the surface,” said Tilmann Denk, a Cassini participating scientist at Freie University in Berlin. “We were able to make use of reflected sunlight from Saturn as an additional light source, which revealed details in the shadows of some of the images.”

Cassini scientists will study data from the gravity science experiment and magnetosphere and plasma science instruments over the next few months as they look for clues about Dione’s interior structure and processes affecting its surface.

Only a handful of close flybys of Saturn’s large, icy moons remain for Cassini. The spacecraft is scheduled to make three approaches to the geologically active moon Enceladus on Oct. 14 and 28, and Dec. 19. During the Oct. 28 flyby, the spacecraft will come dizzyingly close to Enceladus, passing a mere 30 miles (49 kilometers) from the surface. Cassini will make its deepest-ever dive through the moon’s plume of icy spray at this time, collecting valuable data about what’s going on beneath the surface. The December Enceladus encounter will be Cassini’s final close pass by that moon, at an altitude of 3,106 miles (4,999 kilometers).

After December, and through the mission’s conclusion in late 2017, there are a handful of distant flybys planned for Saturn’s large, icy moons at ranges of less than about 30,000 miles (50,000 kilometers). Cassini will, however, make nearly two dozen passes by a menagerie of Saturn’s small, irregularly shaped moons — including Daphnis, Telesto, Epimetheus and Aegaeon — at similar distances during this time. These passes will provide some of Cassini’s best-ever views of the little moons.

During the mission’s final year — called its Grand Finale — Cassini will repeatedly dive through the space between Saturn and its rings.

The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. NASA’s Jet Propulsion Laboratory in Pasadena, California, manages the mission for the agency’s Science Mission Directorate in Washington. JPL is a division of the California Institute of Technology in Pasadena. The Cassini imaging operations center is based at the Space Science Institute in Boulder, Colo. …

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Mysterious ‘Island’ on Saturn Moon Puzzles Scientists | VIDEO

Mysterious 'Island' on Saturn Moon Puzzles Scientists - July 2013

Mysterious ‘Island’ on Saturn Moon Puzzles Scientists

By Mike Wall
space.com
9-30-14

      Saturn’s huge moon Titan just got a little more mysterious.

NASA’s Cassini spacecraft has spotted an odd islandlike feature in Ligeia Mare, one of Titan’s largest hydrocarbon seas. Scientists don’t know what to make of the feature, which has apparently doubled in size over the past year or so, from about 30 square miles to 60 square miles (78 to 155 square kilometers).

“Science loves a mystery, and with this enigmatic feature, we have a thrilling example of ongoing change on Titan,” Cassini radar team deputy leader Stephen Wall, of NASA’s Jet Propulsion Laboratory in Pasadena, California, said in a statement. “We’re hopeful that we’ll be able to continue watching the changes unfold and gain insights about what’s going on in that alien sea.” . . .

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Likelihood of alien life on Enceladus bolstered by confirmation of subsurface ocean

New evidence confirms what many scientists already suspected–a liquid water ocean exists beneath the icy surface of Saturn’s moon Enceladus.

Illustration depicting a large interior ocean beneath an ice shell on Enceladus. (Credit: NASA/JPL-Caltech)

Illustration depicting a large interior ocean beneath an ice shell on Enceladus. (Credit: NASA/JPL-Caltech)

In 2005, NASA’s Cassini spacecraft discovered water-rich plumes erupting from Enceladus’s south pole, leading researchers to believe the moon contained a subsurface ocean. And scientists feel that new data gathered by Cassini confirms this belief. Cassini measured the moon’s gravitational field, and in reviewing this data, scientists determined that Enceladus has more mass at its south pole than is superficially apparent. Scientific American explains, “Because liquid water is denser than ice, a buried ocean could contribute this hidden mass.”

This body of water in the moon’s southern hemisphere is reportedly as large or larger than Lake Superior in the United States, and is located on top of Enceladus’s rocky core at a depth of approximately thirty one miles.

Candice Hansen-Koharcheck, senior scientist with the Planetary Science Institute, told Discovery News, “There have been clues all along . . . But until you actually get this gravity data, it’s still kind of a circumstantial evidence-story. This is proof of the pudding.”

Artist's impression of Cassini in orbit around Saturn. (Credit: NASA)

Artist’s impression of Cassini in orbit around Saturn. (Credit: NASA)

And Scientific American states that the presence of this ocean “boosts Enceladus’s ranking among the top places in the solar system to look for extraterrestrial life.” According to Cornell University planetary scientist Jonathan Lunine, “There are terrestrial organisms that would be perfectly comfortable in that environment . . . It makes the interior of Enceladus potentially a very attractive place to look for life.”

The Cassini spacecraft has three more scheduled targeted flybys of Enceladus to collect more data before it plunges into Saturn’s atmosphere.

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