Launch of first rover, Spirit: June 10, 2003
Launch of second rover, Opportunity: July 7, 2003
Arrival: January 2004
Panoramic camera, miniature thermal emission spectrometer, Mössbauer spectrometer, alpha proton X-ray
spectrometer, microscopic imager
Two powerful new Mars rovers are currently heading for the red planet. With far greater mobility than the 1997 Mars Pathfinder rover, these robotic explorers may trek as much as 40 meters (44 yards) across the surface in a day. Each rover carries a sophisticated set of instruments to search for evidence of liquid water that may have been present in the planet's past. The rovers are identical to each other, but will land at different regions of Mars.
The landing for each will resemble that of the Pathfinder mission. A parachute will deploy to slow the
spacecraft, rockets will fire to slow it further just before impact, and airbags will inflate to cushion the landing. Upon
reaching the surface, the spacecraft will bounce about a dozen times, and could roll as far as one kilometer (0.6
mile). When it stops, the airbags will deflate and retract and the petals will open up, bringing the lander to an
upright position and revealing the rover.
The landed portion of the mission features a design dramatically different from Mars Pathfinder. Where
Pathfinder had scientific instruments on both the lander and the small Sojourner rover, these larger rovers will carry
all their instruments with them. Immediately after landing, each rover will begin reconnaissance of the landing site
by taking a 360-degree visible color and infrared image panorama. Then they will each leave the petal structure behind,
driving off to begin exploration.
Using images and spectra taken daily from the rovers, scientists will command the vehicle to go to rock and
soil targets of interest and evaluate their composition and their texture at microscopic scales. Initial targets may be
close to the landing sites, but later targets can be far afield. These rovers will be able to travel almost as
far in one Martian day as the Sojourner rover did over its entire lifetime.
Rocks and soils will be analyzed with a set of five instruments on each rover, and a special device called the
rock abrasion tool will be used to expose fresh rock surfaces for study. Each rover has a mass of nearly 180 kilograms (about 400 pounds). The prime mission for each rover will last three months on the surface.
For more information visit the Athena science package home page, or Mars Exploration Rover's mission page.