Moon of Saturn · Updated May 2026
Rhea.
Rhea is Saturn's second-largest moon at 1,527 km diameter, an icy body with a heavily cratered surface and a thin oxygen-carbon-dioxide exosphere — the first detected around any moon of the outer solar system.
View Saturn system in 3D →Key facts
Tentative 2008 evidence suggested Rhea might have its own thin ring system — which would have made it the first moon known to have rings — but later imaging found no clear signature.
About Rhea
Rhea's leading hemisphere is brighter than its trailing one, marked with bright wispy streaks once mistaken for surface frost and now known to be ice-cliff exposures along tectonic fractures. Its low density (1.2 g/cm³) means it is roughly three-quarters water ice.
How to view Rhea in 3D
Rhea orbits Saturn in real time inside the interactive viewer. Open the parent body to see the orbital geometry, or use the object browser to fly directly to the moon and observe its rotation, surface, and orbit.
Open the Saturn system →Sources & methodology
Numbers cross-referenced with the sources below; updated May 2026.