Mariner 4 was the first spacecraft to photograph Mars during a successful flyby.
NASA launched Mariner 4 on 28 November 1964, and it passed Mars on 14 July 1965. During the encounter, the spacecraft returned the first close-up images of another planet from deep space. The pictures showed a cratered, Moon-like surface in the regions observed.
Mariner 4 carried a television camera system, a magnetometer, a cosmic-ray telescope, and other scientific instruments. It transmitted 21 images, which were assembled on Earth from digital data sent across interplanetary space. The images transformed scientific expectations about Mars by showing that its surface was not dominated by canals or dense vegetation.
Mariner 4 was a flyby spacecraft, not an orbiter or lander. Later Mariner missions photographed additional regions at closer range, while Mariner 9 became the first spacecraft to orbit Mars. This distinction makes Mariner 4’s achievement specifically the first successful close photographic flyby.