This two image mosaic of Mercury was constructed from photos taken by Mariner 10 a few hours before the spacecraft's closest and first encounter with the planet on March 29, 1974. (Calvin J. Hamilton, and NASA)
This two image mosaic of Mercury was constructed from photos taken by Mariner 10 a few hours before the spacecraft's closest and first encounter with the planet on March 29, 1974. (Calvin J. Hamilton, and NASA)