Mars Pathfinder Lander and Sojourner Rover
Mars Pathfinder was the first spacecraft to land on the surface of the Red Planet since the Viking mission in 1976. The artifact is a full-scale engineering prototype for a spacecraft that was launched on December 4, 1996. On reaching Mars on July 4, 1997, the spacecraft entered the planet's thin atmosphere, was slowed by a parachute and then rockets, and then landed by bouncing on inflated airbags. The protective aeroshell then unfolded to provide the three flat platforms, one of which held a rover (Sojourner).
Pathfinder had a TV camera and scientific instruments to gather scientific data on the Martian atmosphere and weather, as well as solar cells to provide power and communications. The lander operated for over 90 days, during which it relayed 2.3 gigabits of data including that gathered by Sojourner. Some of this data suggest the presence of large amounts of water on Mars in the distant past. The spacecraft as well as the prototype were designed and built by JPL for NASA's office of Space Science.
This engineering model was transferred to the Museum by NASA in 1999.
More information: Mars Pathfinder Lander and Sojourner Rover