The rover is helping us understand the geologic history of the landing site.

Matt Golombek video
Matt Golombek audio --

Now the rover is fundamental. If all we could do was take pictures, we wouldn't know what those compositions are because we couldn't get our little APX up against those materials. So rovers have shown fundamentally that they are they way to go. If you want the ability to sample different materials out in the field, if you want the ability to go up to those different soil types you have to have mobility; that really is needed for a mission that is kind of like Pathfinder or a longer range rover mission. You have to plan the hardware and the instruments to the kind of science and the landing site, they are all sort of coupled together.

Joy Crisp video
Joy Crisp audio --

By having this rover, which we can send out and explore for us and look up close at things and change the terrain by digging its wheels and running over rocks, we have a lot of things we can then watch from the lander camera. But it's almost like our extended arm and eyes that can go out and look at these things and I think that's really going to improve our understanding of the site compared to Viking 1 and 2. And I would hope we'd be able to understand the geologic history of this site. My hope would be that that would happen in a couple of months, that we'd actually have a better idea of the order in which things happen and how these rocks were brought here and what their histories are.