NASA Officials Move to Replace Space Shuttle’s Faulty Engines

KENNEDY SPACE CENTER, Fla. — NASA officials laid out plans Friday to replace the space shuttle Discovery’s engines, which fired and then cut off three seconds before launch.

Shuttle managers are attempting to keep Discovery’s repeated launch delays from bumping the year’s last scheduled flight, the Hubble Space Telescope repair mission in December, into 1994.

“It’s the golden child,” National Aeronautics and Space Administration spokesman Bruce Buckingham said. “Not to downplay the others, but there’s a great deal of interest in the Hubble mission.”

Discovery’s engine shutdown virtually guarantees that NASA will be unable to carry out its plan for eight shuttle flights this year. Four missions have been completed so far.

To save time, NASA managers will remove Discovery’s main engines next week and replace them with three that were to have been installed on the shuttle Endeavour for the Hubble repair mission. Endeavour, in turn, will get three other engines, including one removed from Discovery.

Replacing shuttle engines is easier and quicker than repairing and reinspecting them at the pad. The engines are interchangeable, and they are routinely removed after flights for maintenance.

Engineers say they believe that Thursday’s engine shutdown was caused by a sensor that failed to monitor the flow of fuel in a main engine. A stuck valve resulted in an engine shutdown on the shuttle Columbia in March.

NASA estimates it will be at least three to four weeks before Discovery can fly. Its satellite-delivery mission is already one month late because of three earlier delays, two for mechanical failures and one for this week’s meteor shower.