(FORTUNE Magazine) – People think that driving a rover is like driving a car, but it's not. Since Mars is more than 100 million miles away, even at the speed of light the radio signals coming from those football-field-sized antennas take ten minutes to get there. So, say you're driving and you see a cliff--really what you are seeing is ten-minute-old data. By the time you say, "Don't go over the cliff!," it is too late. Losing any contact with the Spirit rover is stressful. We are still communicating, and getting information back, but it is not what we expect. I'm optimistic though. I was 9 years old when they landed on the moon--that led me to want to pursue math and science. I've been working here for 18 years. We're exploring the surface of Mars so if, as the President stated, we send people to Mars, we'll know where to go to do the best science. One of the weirder things about the job is that since the Rover is powered by the sun, we need to be tied to the Martian day, which is about 37 minutes longer than an Earth day. --Interview by Julie Schlosser