On 27 March 2012, NASA's Saturn-orbiting Cassini spacecraft will make its closest flyby yet over the south polar region of Saturn's geologically-active moon Enceladus, where icy particles and water erupt from fissures. This lowest pass will be at an altitude of about 74 km, above Enceladus’ surface.
Enceladus (504 km across) is a small icy moon. It is one of few Solar System objects known to show on-going volcanic activity. In 2005, Cassini discovered large plumes of cold vapor and icy particles emanating from Enceladus’ south pole. This amazing phenomenon is a rare type of volcanic activity, known as ice volcanoes or cryovolcanoes.
Cassini will attempt to examine particles from the plumes. Scientists will study the data, to learn more about the composition, density and variability of the plume’s material. Cassini’s instruments will also analyze Saturn's magnetic influence near Enceladus, sample the ejected material, and image the moon’s surface.
A flyby in October 2015 will bring Cassini even closer to Enceladus’ south pole. Cassini's closest approach of Enceladus occurred on 9 October 2008, when the probe came to within about 25 km of Enceladus’ surface at the equator.
Enceladus orbits Saturn every 1.4 days, at a distance of about 238,000 km. In Greek mythology, Enceladus was a brother of Cronus (Saturn), son of Uranus, god of heaven, and Gaia, goddess of Earth.
References
NASA
www.nasa.gov/
Wikipedia