Full-scale models of three generations of NASA Mars rovers show the
increase in size from the Sojourner rover of the Mars Pathfinder project
that landed on Mars in 1997 (center), to the twin Mars Exploration Rovers
Spirit and Opportunity that landed in 2004 (left), to the Mars Science
Laboratory rover for a mission to land in 2012 (right).
The Mars Science Laboratory rover is about 9 feet wide, 10 feet long (not
counting its robotic arm) and 7 feet tall.
The Mars Science Laboratory rover will have a mass of about 875 kilograms
(1,929 pounds), compared with 174 kilograms (384 pounds) for each of the
Mars Exploration Rovers and with 11 kilograms (24 pounds) for Sojourner.
The main reason for the growth is to carry a larger payload of science
instruments: about 83 kilograms (183 pounds) for the Mars Science
Laboratory rover compared with 16 kilograms (35 pounds) for the Mars
Exploration Rover and 1.4 kilograms (3 pounds) for Sojourner.
This image was taken in May 2008 at NASA's Jet Propulsion Laboratory,
Pasadena, Calif., which has built the real Mars rovers and managed the
rover missions for NASA's Science Mission Directorate, Washington. JPL is
a division of the California Institute of Technology.