Cassini Prepares For Close Flyby of Saturn’s Geyser-Spewing Moon

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Saturn’s tiny moon Enceladus is of big interest to planetary scientists trying to understand the dynamics of the moon’s geysers and fissures. On August 11, the Cassini spacecraft will swoop by Enceladus for a close flyby, just 50 kilometers (30 miles) from the surface, with the fractures, or “tiger stripes” near the moon’s south pole, where icy jets erupt as the target of study for the Cassini instruments. “Our main goal is to get the most detailed images and remote sensing data ever of the geologically active features on Enceladus,” said Paul Helfenstein, a Cassini imaging team associate at Cornell University in Ithaca, NY. “From this data we may learn more about how eruptions, tectonics, and seismic activity alter the moon’s surface. We will get an unprecedented high-resolution view of the active area immediately following the closest approach.”

Cassini will actually try to see inside one of the fissures in high resolution, which may provide more information on the terrain and depth of the fissures, as well as the size and composition of the ice grains inside. Refined temperature data could help scientists determine if water, in vapor or liquid form, lies close to the surface and better refine their theories on what powers the jets.

Cassini discovered evidence for the geyser-like jets on Enceladus in 2005, finding that the continuous eruptions of ice water create a gigantic halo of ice and gas around Enceladus, which helps supply material to Saturn’s E-ring. Just after closest approach, all of the spacecraft’s cameras — covering infrared wavelengths, where temperatures are mapped, as well as visible light and ultraviolet — will focus on the fissures running along the moon’s south pole. That is where the jets of icy water vapor emanate and erupt hundreds of miles into space. The image resolution will be as fine as 7 meters per pixel (23 feet) and will cover known active spots on three of the prominent “tiger stripe” fractures.

This will be Cassini’s second flyby of Enceladus this year. During the last flyby in March, the spacecraft snatched up precious samples and tasted comet-like organics inside the little moon. Two more Enceladus flybys are coming up in October, and they may bring the spacecraft even closer to the moon. The Oct. 9 encounter is complimentary to the March one, which was optimized for sampling the plume. The Oct. 31 flyby is similar to this August one, and is again optimized for the optical remote sensing instruments.

The Cassini web page has a mission blog that will follow the fly by, and you can also find images and videos as well.

News Source: NASA