Engine Problem Could Delay Endeavour Launch

NASA began the countdown Friday to launch the space shuttle Endeavour on an Earth-mapping mission, though concern about a potential engine problem could delay the flight.

Newly discovered damage to an engine that propelled Discovery into orbit last month could prevent Endeavour from blasting off Monday afternoon. Shuttle managers want to understand the problem before clearing Endeavour for flight.

NASA test director Doug Lyons said a metal seal in a high-pressure fuel turbo pump was chafed more than usual during Discovery’s Dec. 19 launch on a mission to repair the Hubble Space Telescope. A groove was caused by the turbine blades, he said.

The seals help direct hot gas into the blades to increase engine performance.

The pump and its engine worked fine despite the additional wear on the seal, and the astronauts faced no additional risk during their launch, Lyons said. If the seal had failed and the pump had faltered, it is possible the engine could have shut down and forced an emergency landing.

“It certainly is a key component of the pump, and so that’s why we’re taking the extra precaution to go and do this thorough evaluation,” Lyons said. “While we don’t think there’s anything of significance there, we want to make sure we’re not overlooking anything.”

Lyons said the problem was detected during routine inspections earlier this week, and engineers in California were taking apart the pump to gather more information.

Shuttle managers will review the data and decide today whether the three main engines on Endeavour are safe to fly.

The mission to map most of Earth’s terrain using radar is four months late because of damaged wiring that had to be fixed.

Another potential problem was eliminated earlier this week when NASA cleared Endeavour of any potential tile problems.