We're especially interested in water, whether it's ice, liquid or vapor. Learning more about where the water is today and where it was in the past will also guide future studies about whether Mars ever supported life.
Every time we look with increased resolution, Mars has said, 'Here's something you didn't expect. You don't understand me yet.' We're sure to find surprises.
The desire to explore has really always been a part of the American spirit and Mars is a new frontier. Its a place where you could someday send astronauts to do that kind of exploration.