Mars Pathfinder – Sojourner


The Mars Pathfinder was launched 2nd December,1996. It was the second of NASA’s low-cost planetary missions.

Mars Pathfinder

It consisted of a stationary lander and rover robot, Sojourner. It transmitted data collected data on the atmosphere and surface and also transmitted images that were taken by the rover’s cameras.

Launch Date: 04 December 1996
Arrival Date: 04 July 1997
Launch Vehicle: Delta II
Mass: 264 kg (lander), 10.5 kg (rover)
Power System: Solar panels

The rover “Sojourner” is a six-wheeled vehicle which is controlled by an Earth-based operator, who uses images obtained by both the rover and lander systems. Note that the time delay is about 10 minutes, requiring some autonomous control by the rover. The primary objectives were scheduled for the first seven sols (1 sol = 1 martian day = ~24.7 hours), all within about 10 meters of the lander. The extended mission included more analyses of nearby rock and soil and more tests of the rover capabilities

The landing site for the Mars Pathfinder is at 19.33 N, 33.55 W in the Ares Vallis area.

On July 4, 1997, seven months and 119 million miles (192 million kilometers) from Earth, the Mars Pathfinder space probe made a landing unlike any ever before successfully attempted in space exploration. Pathfinder’s route to Mars was a “ballistic” approach – from the moment it was launched from Cape Canaveral, Florida, on December 4, 1996, the craft was aimed at the Ares Vallis region of Mars. Just four trajectory correction maneuvers were necessary to bring Pathfinder in on target. The feat was not unlike a par four hole of golf, teeing off in Los Angeles, California, and aiming for a four-inch (ten-centimeter) moving hole in Houston, Texas. Moments before reaching the surface, the craft sprouted air bags that cushioned its impact. The next day Sojourner, the first-ever interplanetary rover, rolled off the lander. A new era of Mars exploration had begun.

The name Sojourner was chosen for the Mars Pathfinder rover after a year-long, worldwide competition in which students up to 18 years old were invited to select a heroine and submit an essay about her historical accomplishments. The students were asked to address in their essays how a planetary rover named for their heroine would translate these accomplishments to the Martian environment.

Rocky 7 Prototype

Mars Rover

On Earth, demonstrate new technology concepts for use in a long range (50km) traversal across Mars, scheduled for early in the next decade.


Mars Pathfinder Project Information:
Sojourner Rover Home Page
Mars Rover Fact Sheet

Mars Pathfinder Links:

Mars Pathfinder Home:
Mars Pathfinder Mission – Home Page:
RedColony’ Pathfinder:

Mars Rover Fact Sheet
Sojourner Rover Home Page

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