Artist’s rendering of the MESSENGER (an acronym of MErcury Surface, Space ENvironment, GEochemistry and Ranging) spacecraft orbiting Mercury. Credit: NASA.

New observations by NASA’s Mercury Surface, Space Environment, Geochemistry and Ranging spacecraft have confirmed a long-held hypothesis that Mercury harbors abundant water ice and other frozen volatile materials in its permanently shadowed polar craters. Scientists discuss the development with media at NASA Headquarters in Washington on Nov. 29.