Mars Exploration Rovers
The Mars Exploration Rovers are six-wheeled robotic vehicles that are exploring the surface of Mars. The rovers are powered by solar panels. The rovers are robotic "geologists" that are looking at and testing Martian rocks and soil. They are specially designed to search for rocks and minerals that might have formed in water.
The rovers are about the size of a golf cart. Each vehicle has a mass of 170 kilograms. Each weighs 375 pounds on Earth, but just 140 pounds on Mars, where the gravity is weaker.
The top speed of the vehicles is five centimeters (2 inches) per second. The rovers can travel up to 40 meters (130 feet) each Martian day. They probably will not go that far on most days. Instead, they will probably make frequent stops to look around and examine rocks. Engineers think the rovers can keep on working for about 90 Martian days. They could travel as far as one kilometer (0.6 miles) during that time.
Each rover has nine cameras. Six of the cameras help the robot steer and avoid rocks and craters. One is a microscopic imager that takes detailed close-up views of rocks. Two cameras are side-by-side on top of a mast. The mast is the height of a human (about 1.4 meters, or five feet, above the ground). The twin cameras on the mast will shoot pairs of images that can be made into 3D pictures. Because those cameras are about the same height as a person, and there are two "eyes" like we have, the views they give us are a lot like having a person standing on Mars!
Each rover has a robotic arm. The arm has several instruments on it that it is using to examine rocks and soil. Two of those instruments are collecting data about the kinds of minerals and elements that are in the soil and rocks. The arm has a scraper, called a RAT (Rock Abrasion Tool), which it uses to scrape off the outer surface layer of rocks so the other instruments can look at "fresh" material on the inside of the rocks. The microscopic imager camera is also mounted on the arm.
Each vehicle also has a special type of camera called a Miniature Thermal Emission Spectrometer (Mini-TES). The Mini-TES can see how much heat the rocks and soil give off. Different kinds of rock give off heat at different rates. Mini-TES is helping scientists pick out certain types of rocks that they are especially interested in taking a closer look at.