Following MESSENGER's final Mercury flyby before entering orbit, the map coverage of Mercury is nearly complete. Mariner 10 mapped about 45% of the planet (green outline). MESSENGER covered another 20% on its first flyby (blue outline). The second flyby nailed 25% more (red outline). The most recent flyby filled in another 5%, including the last missing piece of the equator and mid-latitudes. Now only 5% of the planet remains unmapped, most of it poleward of 60° north and south latitude.

NASA / JHUAPL / CIW