Object Analysis

Enceladus is the sixth-largest moon of Saturn. It is about 500 kilometers (310 miles) in diameter, about a tenth of that of Saturn's largest moon, Titan. Enceladus is mostly covered by fresh, clean ice, making it one of the most reflective bodies of the Solar System.

Despite its small size, Enceladus is highly active. In 2005, the Cassini spacecraft discovered plumes of water vapor and icy particles venting from the moon's south polar region. These geysers shoot hundreds of miles into space and are the source of material for Saturn's E ring.

The plumes originate from a subsurface ocean of liquid water buried beneath the icy crust. Analysis of the plume material has revealed salt, organic compounds, and molecular hydrogen—key ingredients for life. This makes Enceladus one of the most promising places in the Solar System to search for extraterrestrial microbial life.