Cassini swoops by Saturn's geyser-spewing moon for closer visit

Img: Artist's impression of Cassini spacecraft.Credit: NASA

The Cassini spacecraft will swoop past Saturn's geyser-spewing moon Enceladus today a mere 50 kilometres (30 miles) from its surface on its second visit this year.

Following on from its previous close encounter in March, the craft will focus on the fissures running along the moon's south pole -- where spectacular geysers emanate spewing hundreds of miles into space. Consisting of icy water vapour, the jets have fascinated scientists since their discovery in 2005.

"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," he said in a NASA statement.

Img: Second artists impression of the Cassini spacecraft orbiting Saturn. Credit: NASA

By capturing images of the fissures, scientists hope to better understand the nature of the geysers, helping them to determine if water lies close to the surface and what powers the geysers. Closer analysis of the surface of the moon will also help determine the size of the ice grains and distinguish other elements mixed in with the ice, such as oxygen, hydrogen, or organics.

"Knowing the sizes of the particles, their rates and what else is mixed in these jets can tell us a lot about what's happening inside the little moon," said Amanda Hendrix, Cassini ultraviolet imaging spectrograph team member at NASA's Jet Propulsion Laboratory, Pasadena, Calif.    

Cassini first discovered evidence of the remarkable geysers in 2005 and during its most recent fly-by in March, was able to fly through one of the eruptions capturing and analysing some of the material.

Scientists expect Cassini to begin beaming back collected data at around 11:31 p.m. EDT (0331 Aug. 12 GMT). Two further passes by the moon have been scheduled for later in the year, on October 9 and October 31.       

The Cassini program is an international cooperative effort involving NASA, the European Space Agency (ESA) and the Italian space agency, Agenzia Spaziale Italiana (ASI), as well as several separate European academic and industrial contributors. In the United States, the mission is managed for NASA's Office of Space Science by the Jet Propulsion Laboratory (JPL),Pasadena, CA.                                        

For detailed analysis of the Cassini mission, see NASA site here.                    

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