As of February 2004, the American Mars Exploration Rover Mission is collecting data from rocks and soils from the surface of Mars.
The Mars Exploration Rover (MER) Mission began on June 10, 2003 , with the launch of a rover called Spirit. NASA launched another rover, Opportunity , on July 7, 2003 . As of February 2004, these rovers are actively collecting data from rocks and soils from the surface of Mars.
These rovers act as robotic geologists. Spirit and Opportunity are much larger and more advanced than Sojourner, the rover from a previous mission to Mars. The objectives of these rovers are to learn more about the history of water at Mars and determine the forces of nature that shaped the landscape. Spirit and Opportunity work to discover whether there could have been life on Mars.
Each rover has a panoramic camera located 1.4 meters off the ground that supply scientists with a human-like view of Mars. The rovers also have a robotic arm that uses instruments to break rocks, take microscopic images, and analyze rock and soil composition. Solar panels help recharge batteries, since energy is needed to operate instruments, to keep equipment heated for proper functioning, and to move the rover.