Icy Shower Poses No Threat for Cassini

Planetary scientists are eagerly awaiting what will be the Saturn-orbiting Cassini spacecraft's closest flyby to one of the planet's major moons. On March 12, 2008, Cassini will swoop within 60 miles (100 km) of the surface of Enceladus.

Two years ago, however, Cassini's imagery revealed that it has ice volcanoes that spew streams of frosty material hundreds of miles into space and into the planet's E ring. Could this frozen debris be a danger to Cassini's instruments? Not according to Larry Esposito (University of Colorado), principal investigator for the spacecraft's Ultraviolet Imaging Spectrograph.

In results presented today at the European Planetary Science Congress, Esposito described UVIS observations that indicate the frozen jets contain particles too small to do any damage. Furthermore, he and his colleagues found no evidence for any high-pressure fountains that could loft larger pieces. Esposito says, "The chances are that Cassini should be unharmed by the flyby."