Defect Search Forces Shuttle Launch Delay

Endeavour’s Earth-mapping mission was delayed Monday hours after the countdown began to allow NASA time to check for defects that could lead to a shuttle engine shutdown or an explosion.

The countdown clocks began ticking late Monday morning toward a Thursday liftoff. But by late afternoon, the launch had been bumped to Friday so technicians could check the oxidizer pump of each main engine for bad parts.

If an inspection today finds anything suspicious or inconclusive, a more detailed check will be made, delaying liftoff by about another week, NASA spokesman Bruce Buckingham said. Replacing a pump or the entire engine would take several weeks, he said.

A routine inspection of an oxidizer pre-burner pump in California late last week uncovered a defective metal strip in a pressurization line, NASA spokeswoman June Malone said. One of the 11 small strips that direct the flow of liquid oxygen through the pump was pointed instead of rounded.

Engineers fear the pointed shape could cause the strip to crack and send metal chips into the pump, which could cause a main engine shutdown or possibly an explosion.

Endeavour will carry the most sophisticated radar equipment ever built for environmental monitoring from space.

The $366-million instruments will scan rocks in Death Valley, forests in North Carolina and Michigan, waterways in Oklahoma and environmentally sensitive sites elsewhere in the world so scientists can learn more about changes in Earth’s ecology.