Saturn spacecraft returns to the realm of icy moons

Cassini’s orbits had carried it high above the planet’s poles over the past two years, during which the mission’s ability to encounter the moons, apart from Titan, was limited.

Images taken using clear, green, infrared and ultraviolet spectral filters were combined to create these enhanced color views, which offer an expanded range of the colors visible to human eyes in order to highlight subtle color differences across Rhea’s surface. The moon’s surface is fairly uniform in natural color.

The image at right represents one of the highest resolution color views of Rhea released to date.

Both views are orthographic projections facing toward terrain on the trailing hemisphere of Rhea. An orthographic view is most like the view seen by a distant observer looking through a telescope. The views have been rotated so that north on Rhea is up.

NASA/JPL-Caltech/Space Science Institute

A dual view of Saturn’s icy moon Rhea marks the return of NASA’s Cassini spacecraft to the realm of the planet’s icy satellites. This follows nearly two years during which the spacecraft’s orbits carried it high above the planet’s poles. Those paths limited the mission’s ability to encounter the moons, apart from regular flybys of Titan.

Cassini’s orbit will remain nearly equatorial for the remainder of 2015, during which the spacecraft will have four close encounters with Titan, two with Dione, and three with the geyser-moon Enceladus.

The two views of Rhea were taken about an hour and a half apart February 9, 2015, when Cassini was about 30,000 to 50,000 miles (50,000 to 80,000 kilometers) away from the moon. Cassini officially began its new set of equatorial orbits March 16.

The views show an expanded range of colors from those visible to human eyes in order to highlight subtle color variations across Rhea’s surface. In natural color, the moon’s surface is fairly uniform. The image at right represents the highest-resolution color view of Rhea released to date.

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