A New Roving Science Lab Charts a Course for Mars
"It's time to go back to Mars. Once every two years, the orbits of Earth and Mars are aligned just right, so it's 
possible to send a spacecraft from here to there. That special time is now."
"NASA's latest mission, the Mars Science Laboratory (MSL), launched Saturday morning. It's another six-wheeled rover, but much larger than the rovers Spirit and Opportunity that landed on Mars in 2004. They weighed under 400 pounds. MSL weighs nearly a ton and is about the size of a small compact car."
"Another important difference between MSL and its predecessors is it doesn't rely on solar panels for its power. Instead, it's carrying 8 pounds of plutonium that gives off heat that is converted to electricity."