Mars Mission Resumes After Rover Rolls Off Rock

The Mars Pathfinder mission got back on track Saturday after scientists dislodged the Sojourner rover from a rock where it had become stuck, a mission scientist said.

Sojourner was wedged up against a rock dubbed Yogi after a fender-bender Thursday, and had remained there because of a communications glitch.

The rover failed to receive its new instructions because mission controllers at NASA’s Jet Propulsion Laboratory in Pasadena turned on Pathfinder’s receiver 11 minutes after commands were sent via the Deep Space Network.

During the fender-bender incident, the Sojourner backed into the rock too fast and one of its rear wheels rode up onto the rock’s surface.

On Saturday, scientists managed to drive the Sojourner away from Yogi and then back up to it without incident to resume its historic mission on the Red Planet.

Mission manager Richard Cook said the rover would spend Saturday analyzing Yogi with its alpha proton X-ray spectrometer to determine the rock’s chemical composition.

In a similar analysis earlier in the week, the Sojourner found that another rock, named Barnacle Bill, was identical to rocks on Earth, leading JPL scientists to the conclusion that the Earth and Mars were solar twins in terms of their development.

The rover had been due to survey Yogi on Wednesday but that was put off because photographs taken by the Pathfinder lander showed the rock--about four times larger than the microwave-oven-size Sojourner--had a dangerous overhang that could have damaged the vehicle’s vital solar panels.

Thursday’s fender-bender further delayed the mission, and Friday’s communications glitch added to the problem.

But Cook said the setback was minor, adding that the rover was capable of roving the Martian surface for several more months and that spending four or five days on one rock was “well within Sojourner’s capabilities.”

“It’s a little thing,” he said.

The rover’s next target is a rock about 10 yards from Yogi, called Scooby Doo, which is of particular interest to scientists because it has a whitish hue, the first pale-colored rock seen on Mars.

JPL engineers hope to send the Sojourner over to Scooby Doo early next week after it carries out soil sampling experiments between Yogi and the white rock.