Which NASA mission landed the first rover on Mars?

Mars Pathfinder was the NASA mission that landed the first rover to operate on Mars. It reached the Martian surface on July 4, 1997, carrying the small Sojourner rover and a stationary lander later named the Carl Sagan Memorial Station.

Sojourner weighed about 10.6 kilograms and moved on six wheels, examining rocks and soil near Pathfinder’s landing site in Ares Vallis. It used cameras and scientific instruments to study the terrain while communicating through the lander. The mission demonstrated that relatively small, lower-cost spacecraft could successfully land and conduct useful operations on Mars.

Mars Pathfinder is sometimes confused with Mars 3, which achieved the first soft landing on Mars in 1971. Mars 3’s lander stopped transmitting after less than two minutes, and its small Prop-M rover never became operational. Viking 1 landed earlier than Pathfinder but was a stationary lander, not a rover.

The later Mars Exploration Rovers, Spirit and Opportunity, were more advanced successors. They arrived in 2004 and operated for years, but they were not the first Martian rovers.