For the first time, Mars revealed some of its mysteries when Mariner 4 returned images of the surface of the planet from deep space in 1965. These were the first close up images ever taken of Mars and proved without doubt that the planet wasn't covered in water filled canals. Mariner managed to produce just 21 images showing a barren surface, pock marked with craters. The 1.3 meter probe was powered by 28,224 solar cells contained in the four solar panels, providing 310Watts when it passed Mars.

The camera began taking photos on July 15 and captured 21 pictures using alternate red and green filters. The images taken during the flyby were stored in the onboard tape recorder. Transmission of the taped images to Earth began but was so laborious that it continued until 3 August. All images were transmitted twice to ensure no data was missing or corrupt. The total data returned by the Mariner 4 was 5.2 million bits (about 634kB).