People on Mars possible in 20 to 30 years
People could land on Mars in the next 20 to 30 years provided scientists can find water on the red planet, the head of NASA's surface exploration mission said on September 16.
Two partially solar-powered "robot geologists" -- Mars Exploration Rovers, or MERs -- have been trundling across 3 miles of the planet and into craters since January, beaming back data about the makeup of what scientists believe is Earth's sister planet.