NASA's Mars rovers keep getting bigger. This photo provides a comparison
of the wheel sizes for three generations of them. The first rover on Mars was
Sojourner, on the Mars Pathfinder mission launched in 1996. It was small and
didn't go far. The Mars Exploration Rovers Spirit and Opportunity, launched in
2003, are bigger and have driven many times farther than expected. The Mars
Science Laboratory, in development for a 200 launch, represents another leap
in capability. It will carry its onboard chemistry laboratory long distances.
NASA's Jet Propulsion Laboratory, a division of the California Institute of
Technology, Pasadena, built Sojourner, Spirit and Opportunity, and is building
the Mars Science Laboratory. It has managed these missions for the NASA
Science Mission Directorate, Washington.
