NASA researchers are developing new prototype robots that can drive up steep hills and descend almost-vertical cliffs. Working alone or as a team, these autonomous robotic explorers may go where no rover has gone before — the cliffs of Mars. Recent Mars Global Surveyor images suggest water outflows near cliff edges and the possibility of rich water-borne mineral deposits that extend all the way to the cliff base. “We know that some of the most exciting Mars science and history will be in very rough, currently inaccessible terrain. Getting to those hard-to-reach spots — navigating and exploring them — will require altogether new types of robotic vehicles,” said Dr. Paul Schenker, supervisor of the Mechanical and Robotics Technologies Group at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., and principal investigator for the All-Terrain Explorer.