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News | March 2, 2010

Helene (Quasi-targeted) Flyby - March 3, 2010

The Cassini spacecraft reveals details on the surface of small, irregularly shaped Helene in this close-up view, which was acquired at a distance of approximately 39,000 kilometers (24,000 miles) from the moon on July 20, 2007

The Cassini spacecraft reveals details on the surface of small, irregularly shaped Helene in this close-up view, which was acquired at a distance of approximately 39,000 kilometers (24,000 miles) from the moon on July 20, 2007

Helene Quasi-targeted Flyby

A day after a targeted flyby of the moon Rhea, the Cassini spacecraft made its closest approach of the mission to Helene at about 1,800 kilometers (1,131 miles). The small moon is referred to as a Trojan moon because it is gravitationally tied to the much larger moon Dione.

On approach the Visible and Infrared Mapping Spectrometer (VIMS) took measurements that may help scientists analyze Helene's surface composition and understand if it is coated with particles from the E ring. Then, using a "skeet shoot"-style observation due to quickly changing geometries, the Imaging Science Subsystem (ISS) captured close-ups of the moon. Scientists hope these new views may reveal clues about Helene's past, including how it got gravitationally captured by the larger moon Dione and whether a collision was part of its past.