NASA's first attempt to land on another planet. The primary mission was to image the Martian surface, test the composition of the atmosphere and surface, and search for evidence of life.
The project consisted of two spacecraft launched in 1975. They both entered Martian orbit in 1976 and each dispatched a lander to make surface measurements while the orbiters imaged the planet's surface.
The spacecraft remained in operation until 1980, gathering immense amounts of data on Earth's neighbor.
