Transcript:Three Years on Mars: Spirit's Story Narrator: Scientists expected the Mars Rovers Spirit and Opportunity to run for three months. Three years later the hardy rovers are still operating on opposite sides of the red planet. This is Spirit's story. Scott Maxwell, Mars Exploration Rover Planner Opportunity is very much the glamour girl. She just lands where there is evidence for water and Spirit is a little more the serious sister. She really had to work a little more for everything she accomplished. Narrator: Scientists realized these plains of Gusev Crater didn't have the water story everyone was looking for and they wondered, could the hills harbor the pot of gold? Chris Leger, Mars Exploration Rover Planner They basically just gave us the keys for a couple of months and said get the rover to the Columbia Hills by Sol 160. John Callas, Mars Exploration Rover Mission Manager We started to find the water story in the Columbia Hills. We have made very important discoveries within the rocks. Mineral types that we believe formed in water. And both Spirit and Opportunity have done that through their missions. Narrator: The discoveries didn't come without challenges. Ashitey Trebi-Ollennu, Mars Exploration Rover Mobility Engineer We design all these rovers to go and do science on flat terrain, but we go to Mars and find out that all the high priority science are on slopes and mountains. Narrator: A climber himself, Chris Leger helped Spirit with Martian mountaineering. Leger: If you look at a map of our traverse we started on the north side and then traversed all the way around and then approached it from the west side where we eventually climbed up. Narrator: After scaling the summit of Husband Hill, Spirit's right front wheel stopped rolling and the rover was back-sliding on loose ground. Maxwell: Spirit was definitely in jeopardy. In a very short period of time we had to figure how to drive her with five-wheels, how to get her out of the sand trap she was in and how to get her up on to something dragging one wheel as she went that would enable to point the solar panels at the sun. Leger: And we were watching the solar power curves going down and down every day and the heaters start to come on to keep the vehicle alive. Trebi-Ollennu: We were fortunate to get Spirit just in time to what we call Low Ridge which is a 10 degree slope so we could point spirit 10 degrees towards the sun. Narrator: It was just in the nick of time. Spirit hunkered down for the winter but still managed to do science. The rover found evidence of ice clouds in the atmosphere and snapped the most detailed Martian panorama ever taken. Maxwell: Both rovers have had two brain transplants in the time they've been on the surface of Mars. Trebi-Ollennu: Basically, the rover software is probably what you and I know as the10 commandments but it's got more like 1000 commandments. Thou shall not go over a rock over 25 centimeters tall. Thou shall not drive and get a tilt of more than 25 degrees and thou shall not kill yourself. Narrator: With winter gone, Spirit, ever the trooper, is on the move again. Maxwell: She's a stubborn little girl and she's hanging in there and she's not going to give up.