Plains material east of the Caloris basin is shown this image (FDS 191) acquired during the spacecraft's first encounter with Mercury. Several west-facing lobate scarps occur in the hummocky plains interpreted as Caloris ejecta and may be short flow fronts of partially melted ejecta which flowed back toward the basin after deposition.

The Mariner 10 mission, managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, explored Venus in February 1974 on the way to three encounters with Mercury-in March and September 1974 and in March 1975. The spacecraft took more than 7,000 photos of Mercury, Venus, the Earth and the Moon.