Rover’s Grand Exit Gets Dress Rehearsal

Engineers at NASA’s Jet Propulsion Laboratory in Pasadena planned to stage a full-scale dress rehearsal late Sunday night of the events preceding the Spirit rover’s departure from its landing platform, delaying the roll-off for at least a day to late Wednesday and giving scientists more time to take pictures of the Gusev Crater landing site, officials said.

The rover must pivot 120 degrees on top of the lander before crawling down the egress ramp, and engineers want to make sure they have all bases covered before attempting the procedure with the craft.

They spent Saturday working in the “sandbox” laboratory at JPL, practicing the maneuver with an engineering prototype of the rover. On Sunday night, they planned to reproduce the critical maneuvers with an Earth-bound twin of Spirit.

The complicated maneuvering is required because the primary ramp that engineers had hoped to use is partially blocked by one of the collapsed air bags used to cushion the craft’s Mars landing on Jan. 3.

JPL’s Arthur Amador, mission manager for the ninth Martian day, said the actual roll-off will take place in three separate stages over two days.

The rover will pivot 45 degrees to the right, then stop and take pictures of its position. Pasadena engineers will evaluate the pictures to ensure that there are no problems before ordering it to turn another 50 degrees.

After pictures of that maneuver are evaluated, the rover will continue its turn on the second day until it is ready for the roll-off.

The date of the roll-off has changed regularly, bouncing forward and back as events alter the team’s plans. “We adjust the plan every day,” Amador said. “We have to manage our risks and resources.”

Amador noted that everything on the rover seems to be in good shape.