Mars Reconnaissance Oribiter

A cross-section of a thick sheet of underground ice is exposed at the steep slope that appears bright blue in this enhanced-color view of Mars from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter in this image released on January 11, 2018. NASA/JPL-Caltech/UA/USGS/Handout via Reuters

Thick Sheets of Water Ice Found Buried Under Mars’s Surface