By Jennifer Bails

Like most Carnegie Mellon faculty, research professor Tony Stentz is too busy to wait by the computer all day. But on February 7, the robotics professor checked e-mail more than his hectic schedule usually permits, hoping for one particular message.

That morning, NASA scientists had challenged the Mars Exploration Rover named Opportunity, to maneuver on its own around a simulated obstacle using software called Field D-Star. The software–developed by Stentz with one of his graduate students, Dave Ferguson–enables a robot to build a detailed map of surrounding terrain, giving it memory of its route and the ability to retrace steps.

NASA is counting on Field D-Star to give Opportunity and its twin rover, Spirit, the ability to avoid roadblocks and find their way out of dead ends. The scientific payoff could be huge–less time troubleshooting rovers trapped 283 million miles away, which leaves more time for unlocking the Red Planet's mysteries.

Stentz knew Field D-Star worked well on Earth, but he wasn't so sure about what would happen in the hostile Martian environment. In its first live test run in space, the software was supposed to steer Opportunity around a virtual six-foot-wide circle on the edge of a stadium-sized impact crater.

Word of success sent by satellite from Opportunity to NASA didn't come until late evening two days later. Stentz, who was still up working, received an email moments later. "I'm not prone to large emotional swings," Stentz says, "but it was certainly a thrill when I got that email." Then, he says, he went to bed.

A few more tests and Field D-Star could be ready to guide the rovers full-time, says Carnegie Mellon alumnus and NASA researcher Mark Maimone (SCS'96) . "With Tony's software, the rover can handle any number of obstacles in any combination–and be much smarter about it."