On July 4, 1997, Mars Pathfinder landed in an ancient flood plain in Mars northern hemisphere known as Ares Vallis. This area, among the rockiest parts of the red planet, was chosen because scientists believed it to be a relatively safe surface to land on and one which contained a wide variety of rocks.
The mission, originally designed as a technology demonstration of a way to deliver an instrumented lander and a free-ranging robotic rover to the surface of Mars, far succeeded this goal. Pathfinder returned an unprecedented amount of data and surpassed its primary design life.
Over the life of its mission, ending 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, as well as more than 15 chemical analyses of rocks and soil and extensive data on winds and other weather factors.