An artist's depiction of what one of the MER rovers may look like on the surface of Mars. Click on image for full size (68K JPEG) Image courtesy NASA/JPL.

The Mars Exploration Rovers are six-wheeled robotic vehicles that are exploring the surface of Mars. The rovers, powered by solar panels, are robotic "field geologists" that are examining Martian rocks and soil for signs of the presence of liquid water in Mars' past. The top speed of the vehicles, which are about the size of a golf cart, is five centimeters (2 inches) per second. Allowing for rocky ground and factoring in caution while negotiating rough terrain, the rovers are expected to travel up to 40 meters (130 feet) each Martian day. The vehicles are designed to survive for 90 Martian days, traveling a total of about one kilometer (0.6 miles) during that time.

Each rover has nine cameras. Six of the cameras are for navigation and hazard avoidance, one is a microscopic imager for taking detailed close-up views of rocks, and a pair that are mounted atop a mast roughly the height of a human (about 1.4 meters, or five feet, above the ground) shoot stereoscopic panoramas of the rover's surroundings. The vehicle has a mass of 170 kilograms, so it weighs 375 pounds on Earth but just 140 pounds in the weaker Martian gravity.

The rover has a robotic arm carrying several instruments that it is using to examine rocks and soil. The Mössbauer Spectrometer analyzes the mineral content of iron-bearing soil and rocks. The Alpha Particle X-Ray Spectrometer (APXS) determines the abundances of various elements in rock and soil samples. A Rock Abrasion Tool (RAT) mounted on the arm grinds away the outer, weathered surface of rocks to allow the other instruments to examine "fresh" material within. The microscopic imager camera is also mounted on the arm.

Magnets mounted on the rover's body collect magnetic dust particles from the air and ground up minerals scraped from rocks by the RAT, helping to characterize the iron content of those materials. The vehicle also carries a Miniature Thermal Emission Spectrometer (Mini-TES) that is helping scientists identify rocks and soil that warrant a closer look, determine the processes that formed specific rocks, and gather data on temperature profiles of the Martian atmosphere (when pointed skyward).

This is what an artist thinks one of the MER rovers looks like on the surface of Mars. Click on image for full size (68K JPEG) Image courtesy NASA/JPL.

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.

This is what an artist thinks one of the MER rovers looks like on Mars. Click on image for full size (68K JPEG) Image courtesy NASA/JPL.

The Mars Exploration Rovers are robot vehicles that are exploring the surface of Mars. The rovers have six-wheels and are powered by solar panels. The rovers are "geologists" that are looking at rocks and soil on Mars. They are trying to find 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. Since the gravity on Mars is weaker, each rover weighs just 140 pounds on Mars.

The rovers aren't very fast. Their top speed is five centimeters (2 inches) per second! They 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 stop pretty often to look around and do tests on rocks. Engineers think the rovers can keep on working for about 90 Martian days. They may 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 keep it from running into rocks or falling into craters. One is a microscope camera that takes close-up views of rocks. Two cameras are on top of a pole that is about as tall as a person. They are giving us views of Mars that are like what we would see if we were standing on Mars!

Each rover has a robot arm. The arm has instruments on it that it uses to examine rocks and soil. Two of those instruments tell us 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. After the rock's surface has been scraped clean, the other instruments can look at "fresh" material on the inside of the rock. The microscope camera is also on the arm.