Launch of first rover, Spirit: June 10, 2003
Launch of second rover, Opportunity: July 7, 2003
Arrival: January 2004
Science instruments: Panoramic camera, miniature thermal emission spectrometer, Mössbauer spectrometer, alpha proton X-ray spectrometer, microscopic imager
Mars Exploration Rover
In 2003, two powerful new rovers were sent to Mars. The rovers are named Spirit and Opportunity. The names were chosen in an essay contest open to students in kindergarten to 12th grades. Spirit and Opportunity were the names suggested by the winner of the contest -- a third-grader from Arizona. Spirit landed on Mars on January 3, 2004. Opportunity is scheduled to land on Mars on January 24, 2004.
These robotic explorers are able to move much better than the 1997 Mars Pathfinder rover. These rovers will be able to trek up to 40 meters (about 44 yards) across Mars in a Martian day. Each rover will carry an advanced set of instruments. These complex tools will let the rover search for proof of liquid water. The water may have been present in the planet's past. The rovers are identical to each other. However, they will explore different regions of Mars.
The landing for each is like that of the Pathfinder mission. A parachute opens to slow the spacecraft. Rockets fire to slow it further just before impact. Then, airbags inflate to cushion the landing. Upon reaching the surface, the spacecraft bounces about a dozen times. It could roll as far as 1 kilometer (0.6 miles). When it stops, the airbags deflate and retract. Then the petals open up. This brings the lander to an upright position and reveals the rover.
The landings will be like the Mars Pathfinder. But, the on-the-ground mission will be very different. Pathfinder had scientific instruments on both the lander and the small Sojourner rover. These larger rovers will carry all their instruments with them. As soon as they land, each rover begins exploring the landing site. They take a 360-degree visible color and infrared image of the landscape. Then they each leave the petal structure behind. They drive off to begin exploration.
Scientists tell the vehicle to go to the rock and soil targets that they want to see. They will use the images taken daily from the rovers. The scientists will then study the makeup of the rocks and soil using the microscopes on the rovers. The rovers will first study areas around their landings sites. Later, targets can be farther away. These rovers are able to travel almost as far in 1 Martian day as the Sojourner rover did over its entire lifetime.
Rocks and soils will be studied with a set of five instruments on each rover. A special tool called the "RAT," or rock abrasion tool, will be used. RAT will uncover fresh rock surfaces for study. Each rover has a mass of nearly 180 kilograms (about 400 pounds). Each will be able to move up to 40 meters (about 44 yards) per sol, or Martian day. Surface operations will last for at least 90 sols. This will be in late April 2004, but the missions could continue longer. The length of the mission will depend on the health of the vehicles.
Excerpt from the Jet Propulsion Laboratory website