The Mars Rover is a National Aeronautics and Space Administration (NASA) project launched in June 2003 and that landed on the red planet in January 2004. Two rovers, named Spirit and Opportunity, were designed to be robotic geologists, collecting data as they roam the surface of Mars. Each robot has features that NASA described as similar to what any living creature would need during exploration: a body, or structure, to protect the rover’s vital organs; brains, or computers, to process information; temperature controls, including internal heaters and insulation to protect the structure from the elements; a neck and head, or a mast for the cameras to give the rovers a human-scale view; eyes and other “senses,” or cameras and instruments that give the rovers information about their environment; wheels and legs for mobility; arms for reaching; and the ability to communicate, via antennas for “speaking” and “listening.” The rovers are powered by batteries and solar panels.

Since the first data began to be returned to Earth in early March 2004, the rovers have provided scientists with data and impressive images for research and study. A dramatic finding from the twin rovers was the discovery that the arid planet had once been wet and possibly habitable: Based on data collected by Opportunity, researchers concluded that “liquid water was once intermittently present at the Martian surface.” Observers can track the progress of Spirit and Opportunity, each exploring different areas of the red planet, at the NASA Web site (http://marsrovers.jpl.nasa.gov/home/index.html).