Leader of the team that created the cameras on the Mars Rovers, Jim Bell discussed the Rover missions as well as conditions on the Red Planet. Both Spirit and Opportunity have far exceeded expectations on how long they would last. It was hoped they would function for 90-100 days, and both have been running over 1,000 days, he reported. They also traveled further than expected, with Spirit driving four miles, and Opportunity six.
The major finding of the Rover missions is the confirmation thatliquid water existed on the planet's surface a long time ago, said Bell. Evidence for this comes from the presence of minerals such as jarosite, which needs water to form. The Rovers can't tells us the age of rocks on the planet, but he estimated they are around 3-4 billion years old in the areas they explored.
Prof. Bell shared his thoughts on some of Mars' seemingly anomalous features. While he believes there are many striking land forms on the planet, he doesn't view the 'Face on Mars' as representing something artificial. Similarly, in what has been called the Mars Humanoid Skull, he sees an enigmatic rock rather than a smoking gun for past intelligent life. However, he did note that he is supportive of further study of such unusual elements.