On Tuesday, March 2, 2010, NASA's Cassini spacecraft will make its closest encounter yet with Saturn’s second largest moon. This will be the mission’s second targeted flyby of the moon in the mission, so it is sometimes referred to as R-2.
The spacecraft will fly by Rhea at an altitude of about 100 kilometers (60 miles).
To read a scientist's take on the upcoming flyby, click here.
The animation shows the sequence of Cassini’s instruments scanning the moon for data. Among the many activities, the radar instrument will be conducting imaging scans and taking measurements for determining surface composition. The fields and particles instruments will take data that will help us understand the environment of Rhea -- its interaction with Saturn's magnetosphere, its debris disk, and its ejecta cloud density. Remote sensing instruments will make measurements -- in wavelengths as short as the ultraviolet all the way to the far infrared -- of Rhea's surface terrains and composition, as well as its surface temperature. The cameras will be investigating some "bluish spots" that could be related to the debris ring material and the moon’s fractured "wispy" terrain. The visual and infrared mapping spectrometer and the ultraviolet imaging spectrograph will do imaging spectroscopy to search for and map out water ice grain sizes, carbon dioxide, ammonia and fine-grained iron particles, among other materials. The composite infrared spectrometer will map temperatures across portions of Rhea's sunlit disk at high resolution and the cooling of the surface after Rhea enters Saturn's shadow.