dec 4, 1996 - Pathfinder (rover)

Description:

Mars Pathfinder was launched December 4, 1996 and landed on Mars' Ares Vallis on July 4, 1997.
From landing until the final data transmission on September 27, 1997, Mars Pathfinder returned 2.3 billion bits of information, including more than 16,500 images from the lander and 550 images from the rover.
suggest that Mars was at one time in its past warm and wet.