Mars Pathfinder (MPF)

Mars Pathfinder demonstrated a number of innovative, economical, and highly effective approaches to spacecraft and mission design of a planetary landing mission.

The second of the Discovery Program missions, development of the spacecraft and free-ranging surface rover was limited to 3 years and $150 million. No orbiter was used to scout a landing site and deliver the lander to the surface. Rather, the microrover, named Sojourner, was encased in a self-righting tetrahedral lander, which, in turn, was encapsulated in an aeroshell designed to withstand atmospheric entry.

From Viking photos, a landing site had been pre-selected. Slowed in its descent by a system of parachutes and retro-rockets, the lander/rover then fell freely the last few hundred feet, bouncing on its inflated airbags over the Martian surface like a basketball. The airbags deflated, the petals of the lander opened, and the rover descended and began exploring and analyzing nearby rocks. The engineering design far exceeded expectations.

Pathfinder's lander, named for the late Dr. Carl Sagan, operated nearly three times its design lifetime of 30 days, and the Sojourner rover operated 12 times its design lifetime of seven days