The first spacecraft to visit Mercury was NASA's Mariner 10. It stayed in Mercury's orbit from 1974–1975. Mariner 10 provided the first close-up pictures of Mercury's surface. It showed many types of geological features, such as the craters. Unfortunately, the same face of the planet was day at each time Mariner 10 flew close to Mercury. This made close observation of both sides of the planet impossible. In the end, less than 45% of the planet's surface was mapped.