关于这张图
The blue areas on this map of Mars show regions where NASA missions have detected subsurface water ice. Scientists can use the map – part of the Subsurface Water Ice Mapping project, or SWIM – to decide where the first astronauts to set foot on the Red Planet should land. Triangles on the map are past and present Mars missions; circles are ice-exposing impact craters. Mars has both water ice and carbon dioxide ice (dry ice); water ice would be a critical resource for the first astronauts to step foot on Mars, who can use it for drinking, rocket fuel, and other purposes. The more water ice the…