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Cassini reveals ongoing hydrothermal activities within Enceladus

March 12, 2015; Srama, Ralf

An article appeared in the journal Nature by Hsu et al. about findings of the Cosmic Dust Analyzer onboard Cassini. The results have important implications for the habitability of icy worlds. An extensive, four-year analysis of data from the spacecraft, computer simulations and laboratory experiments led researchers to the conclusion the analyzed tiny grains most likely form when hot water containing dissolved minerals from the moon's rocky interior travels upward, coming into contact with cooler water. Temperatures required for the interactions that produce the tiny rock grains would be at least 194 degrees Fahrenheit (90 degrees Celsius).

"It's very exciting that we can use these tiny grains of rock, spewed into space by geysers, to tell us about conditions on -- and beneath -- the ocean floor of an icy moon," said the paper's lead author Sean Hsu, a postdoctoral researcher at the University of Colorado at Boulder.

Cassini's cosmic dust analyzer (CDA) instrument repeatedly detected miniscule rock particles rich in silicon, even before Cassini entered Saturn's orbit in 2004. By process of elimination, the CDA team concluded these particles must be grains of silica, which is found in sand and the mineral quartz on Earth. The consistent size of the grains observed by Cassini, the largest of which were 6 to 9 nanometers, was the clue that told the researchers a specific process likely was responsible.

The Cassini-Huygens mission is a cooperative project of NASA, ESA and the Italian Space Agency. JPL manages the mission for NASA's Science Mission Directorate in Washington. The Cosmic Dust Analyzer (CDA) was developed by the Max Planck Institute for Nuclear Physics (Heidelberg) and the German Space Agency (DLR, Berlin). It is operated by the Institute for Space Systems (IRS) at the University of Stuttgart (Principal Investigator R. Srama). The project is supported by the German Space Administration DLR.

Read the full story on the JPL news page or on the Nature journal homepage.

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