TL;DR: Mars Subsurface Ice Assessment is a main entry in the 外星矿物知识引擎 database.
MRO discovered extensive subsurface ice at mid-latitudes, with pure ice exposed at eroding scarps. This ice is accessible with simple excavation equipment and represents the key resource for Mars ISRU.
Assessment Method
MRO SHARAD radar, Mars Odyssey neutron spectrometer, HiRISE imagery
Estimated Value
Essential for human missions; millions of km³ total