Scientists used data gathered by NASA's Cassini spacecraft during 13 years of exploring the Saturn system to make detailed images of the icy moon - and to reveal geologic activity.

New composite images made from NASA's Cassini spacecraft are themost detailed global infrared views ever produced of Saturn's moon Enceladus. Anddata used to build those images provides strong evidence that the northernhemisphere of the moon has been resurfaced with ice from its interior.

Cassini'sVisible and Infrared Mapping Spectrometer (VIMS) collected light reflected off Saturn, its rings and itsten major icy moons - light that is visible to humans as well as infrared light.VIMS then separated the light into its various wavelengths, information that tellsscientists more about the makeup of the material reflecting it.

The VIMS data,combined with detailed images captured by Cassini's Imaging Science Subsystem,were used to make the new global spectral map of Enceladus.

Cassiniscientists discovered in 2005 that Enceladus - which looks like a highly reflective,bright white snowball to the naked eye - shoots out enormous plumes of icegrains and vapor from an ocean that lies under the icy crust. The new spectralmap shows that infrared signals clearly correlate with that geologic activity,which is easily seen at the south pole. That's where the so-called "tiger stripe"gashes blast ice and vapor from the interior ocean.

Infrared images of Enceladus were used to make this interactive 3D globe. Image Credit: NASA/JPL-Caltech/University of Arizona/LPG/CNRS/University of Nantes/Space Science Institute

But some of thesame infrared features also appear in the northern hemisphere. That tellsscientists not only that the northern area is covered with fresh ice but thatthe same kind of geologic activity - a resurfacing of the landscape - has occurredin both hemispheres. The resurfacing in the north may be due either to icy jetsor to a more gradual movement of ice through fractures in the crust, from the subsurfaceocean to the surface.

"Theinfrared shows us that the surface of the south pole is young, which is not asurprise because we knew about the jets that blast icy material there,"said Gabriel Tobie, VIMS scientist with the University of Nantes in France and co-authorof the new research published in Icarus.

"Now,thanks to these infrared eyes, you can go back in time and say that one largeregion in the northern hemisphere appears also young and was probably activenot that long ago, in geologic timelines."

Managedby NASA's Jet Propulsion Laboratory in Southern California, Cassini was anorbiter that observed Saturn for more than 13 years before exhausting its fuelsupply. The mission plunged it into the planet's atmosphere in September 2017,in part to protect Enceladus, which has the potential of holding conditionssuitable for life, with its ocean likely heated and churned by hydrothermalvents like those on Earth's ocean floors.

TheCassini-Huygens mission is a cooperative project of NASA, ESA (the EuropeanSpace Agency) and the Italian Space Agency. JPL, a division of Caltech inPasadena, manages the mission for NASA's Science Mission Directorate inWashington. JPL designed, developed and assembled the Cassini orbiter.

More information about Cassini can be found here:

https://solarsystem.nasa.gov/cassini

News Media Contact

Grey Hautaluoma / Alana JohnsonNASA Headquarters, Washington202-358-0668 / 202-358-1501grey.hautaluoma-1@nasa.gov / Alana.r.johnson@nasa.gov

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Infrared Eyes on Enceladus: Hints of Fresh Ice in Northern Hemisphere - Jet Propulsion Laboratory