Mariner 10 map of Mercury

Mariner 10 map of Mercury
Mariner 10 map of Mercury Mariner 10 flew by Mercury three times in 1974 and 1975, seeing the same hemisphere sunlit each time. As a result, fully half of Mercury's surface is still terra incognita. Some of the blank area on this map has been imaged from Earth at lower resolution using radio telescopes. USGS / NASA / Mark Robinson / Steve Albers