Saturn's largest and second largest moons, Titan and Rhea, appear to be stacked on top of each other in this true-color scene from NASA's Cassini spacecraft released on Dec. 23, 2013. The north ...

Here’s how it works. Saturn's second-largest moon Rhea has a wispy atmosphere with lots of oxygen and carbon dioxide, a new study has found. NASA's Cassini spacecraft detected Rhea's atmosphere ...

A mystery on Saturn’s moon Rhea may have finally been solved. When NASA’s Cassini spacecraft flew past the planet’s second-largest moon before the end of its mission in 2017, it spotted a ...