LOS ANGELES (AP) - The Mars Pathfinder rover stopped cold automatically when it drove two of its wheels onto rocks, mission officials said Friday.
"Currently, the rover has a front wheel on the rock Torres and a rear wheel on the rock Tigger," Jennifer Harris of NASA's Jet Propulsion Laboratory said in summing up the mission's 41st day on the red planet.
Richard Cook, the Pathfinder mission manager, said the rover had traveled no more than 6 to 9 feet Thursday when its hazard detection system sensed the suspension was too tilted by the grapefruit-sized rocks.
"Whenever it contacts a decent-sized rock or two decent-sized rocks, it will stop. That there were two probably didn't have too much to do with it," he said.
As a result of the automatic stop, the Pathfinder team was considering some changes in rover software that would allow it to be more adventurous as it makes its way around Mars, Harris said.
Cook noted that wear-and-tear has created some drift in the rover's gyro, which provides direction. As a result, the rover has a hard time driving in a straight line or turning, he said.
Engineers on the ground are trying to rely instead on measurements of wheel rotations to establish direction, he said.