Crushed Seal Replaced on Shuttle; Monday Launch Planned

A crushed seal that escaped repeated checks for hydrogen leaking in Columbia’s rear compartment has been replaced, and confident NASA officials scheduled Monday as the date for the shuttle’s fourth launch attempt.

Engineers initially believed that one of Columbia’s three recirculation pumps leaked during fueling last week for NASA’s third attempt to send the shuttle on an astronomy mission. The crushed seal was discovered as technicians checked the newly installed pumps.

NASA spokesman James Hartsfield said Wednesday that the seal apparently was damaged when it was installed improperly after Columbia’s last flight in January. The seal, about 2 1/2 inches in diameter, is part of a valve on a hydrogen line that leads to one of the shuttle’s three main rocket engines.

NASA has been trying to send Columbia on an astronomy mission since May, when the shuttle’s hydrogen leaks first were detected. The space agency replaced the hydrogen lines between the orbiter and external tank, and made minor repairs in the aft compartment.

The new components did not leak during fueling for last week’s launch attempt. But hydrogen flooded the rear compartment, where the pumps and three main engines are located.

The National Aeronautics and Space Administration has only a few days next week in which to launch Columbia. After that, the flight would have to wait until after Discovery’s top-priority mission to send a satellite to study the sun’s polar regions.