Sojourner

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Sojourner was a small rover that was sent to Mars in 1997 as part of NASA's Mars Pathfinder mission.

The six-wheeled Sojourner rover vehicle was only 11 inches tall by 2 feet long by 19 inches wide (280 x 630 x 480 mm). The tiny vehicle, which NASA called a "micro-rover", had a top speed of only 79 feet per hour (0.4 meters/minute). Sojourner had a mass of 11.5 kg, so it weighed about 25 pounds on Earth or just under 10 pounds on Mars.

The rover carried scientific instruments to measure properties of the Martian soil and to do chemical analysis of Martian rocks. It also had three little cameras. A solar panel on the top of the vehicle provided it with electrical power.

The Mars Pathfinder lander, carrying the Sojourner rover, landed on Mars on July 4, 1997. Pathfinder was surrounded by airbags (like the ones in a car that protect people during an accident) that cushioned its landing when it bounced to a stop on the rocky surface of Mars. After the air was let out of the airbags, the lander unfolded itself and Sojourner drove off a ramp and onto the surface of the red planet.

Sojourner explored the area near the lander, never straying more than a few dozen feet from the landing site. The rover traveled a total distance of just over 100 meters (330 feet) in the slightly more than 80 days that it operated on the surface of Mars.

Sojourner on the surface of Mars, examining a large rock named "Yogi".

The surface of Mars as viewed by the "eyes" (camera) of Sojourner.

This picture was taken by a camera on the Mars Pathfinder lander. It shows part of the lander, including the ramp that Sojourner drove down and the deflated airbags that were used to cushion the landing. It also shows sojourner on the surface of Mars, using its instruments to analyze a large rock.

The two rover drivers for Sojourner.

Before Sojourner was sent to Mars, a similar robot (called FIDO) was tested on Earth. FIDO is shown here driving over rocky, Mars-like terrain in the Mojave Desert in California.

NASA scientists built a simulated "Mars yard" at the Jet Propulsion Labs (JPL) in California. They tested robots in the Mars yard before sending Sojourner to Mars.