Image Credit: NASA/JPL-Caltech 

01.17.2012
Three Generations of Rovers with Standing Engineers 
Two spacecraft engineers stand with a group of vehicles providing a comparison of 
three  generations  of Mars rovers developed  at NASA's Jet Propulsion Laboratory,
Pasadena, Calif. The setting is JPL's Mars Yard testing area.

Front and center is the flight spare  for the first Mars rover, Sojourner, which 
landed on Mars  in 1997  as  part  of  the  Mars  Pathfinder  Project.  On  the
left is a Mars Exploration Rover Project test rover that is a working sibling to
Spirit and Opportunity, which landed on Mars in 2004. On the right is a Mars
Science Laboratory test rover the size of that project's Mars rover, Curiosity,
which is on course for landing on Mars  in August 2012.

Sojourner and its flight spare, named Marie Curie, are 2 feet (65 centimeters)
long.  The Mars Exploration Rover Project's rover, including the "Surface System
Test Bed" rover in this photo, are 5.2 feet (1.6 meters) long. The Mars Science
Laboratory Project's Curiosity rover and "Vehicle System Test Bed" rover, on the
right, are 10 feet (3 meters) long.

The engineers are JPL's Matt Robinson, left, and Wesley Kuykendall. The 
California Institute of Technology, in Pasadena, operates JPL for NASA.