The Mars Exploration Rovers will act as robotic field geologists for the Athena science team back on Earth. They will land at
different sites on the planet and investigate them in detail. Each rover might spend several days looking at a rock, taking
close-up images, measuring the composition, and grinding at the surface to reveal the rock's interior. Then the rovers will be
commanded to search for other interesting targets, maybe nearby or perhaps atop some distant hill.
The Mars Exploration Rovers will be intelligent enough to drive long distances without any help from Earth and will know how to pick their way through a martian
landscape full of obstacles. Should something come up that one of the rovers cannot handle alone, it will stop in its tracks and
"phone home." Conducting this kind of research is a race against time. Martian dust will slowly build up on the rovers' solar arrays.
It will eventually block the energy needed to recharge the batteries that keep the rovers alive.