This spacecraft was originally built as a backup to Mariner 4, a Mars craft launched in 1964. When Mariner 4 completed its mission successfully, the backup was rechristened Mariner 5 and reoutfitted for a flyby of Venus.
Launched from Cape Canaveral, Florida, in June 1967, Mariner 5 flew within about 4,000 kilometers (approximately 2,500 miles) of Venus some four months later. Mariner 5's flight path following its Venus encounter brought it closer to the Sun than any previous probe.
Mass: 245 kilograms (540 pounds)
Science instruments: Ultraviolet photometer, cosmic dust, solar plasma, trapped radiation, cosmic rays, magnetic fields, radio occultation and celestial mechanics
Launch: June 14, 1967
Venus flyby: October 19, 1967
