Shuttle Mission Faces Delay Over Orbital System

The last scheduled U.S. shuttle flight this year, a military mission by Discovery, is likely to be delayed because of a faulty component in the orbital maneuvering system, space agency officials said Thursday.

The system provides the thrust for entering orbit, changing orbit and, at the end of a flight, leaving orbit. One of two power units in a signal conditioner, or electronic box, appears to have failed on Discovery’s left orbital maneuvering system pod, NASA spokesman George Diller said.

Engineers were debating whether to replace Discovery’s left pod in the hangar or to remove the pod, replace the affected signal conditioner and then reinstall the pod, Diller said.

National Aeronautics and Space Administration officials had been aiming for a mid-November launch.

Meanwhile, preparations for next week’s launch of the shuttle Columbia are going well, officials said. The countdown for liftoff Thursday is to begin Monday.