Guide Note

After being launched in June of 2003 and arriving on Mars in January of 2004, NASA's twin robot geologists have been exploring the Martian planet. The original mission was only intended to last three months, but the two rovers, named Spirit and Opportunity, continue to provide scientists with thousands of images and geological samples more than four years after launching.

Fast Facts

1. Rover weight: 380 pounds
2. Each rover's communication antenna is as small as a human thumb
3. It was announced on June 28, 2007 that Opportunity would descend a 200-foot-deep crater to search for ancient signs of water
4. There are concerns that Martian dust storms could prevent the recharge of the rovers' solar powered batteries
5. On May 25, 2008, a third rover, named Phoenix landed on Mars to explore the planet's Arctic region

1. Determine whether Life ever arose on Mars
2. Characterize the Climate of Mars
3. Characterize the Geology of Mars
4. Prepare for Human Exploration