Mariner probesA series of US planetary probes. Mariners 2 and 5 made close-up observations of Venus while Mariner 10 became the first two-planet probe, visiting Venus and Mercury. Mariners 4, 6, 7, and 9 were successful Mars probes, the latter becoming the first man-made orbiter of another planet. Mariners 11 and 12 were renamed Voyagers 1 and 2. Mariners 1 (to Venus) and 8 (to Mars) suffered launch failure while Mariner 3 failed to achieve its intended trajectory to Mars.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006