Nasa doubts September shuttle launch

CAPE CANAVERAL, Florida - There is virtually no chance of a shuttle launch in September, a top National Aeronautics and Space Administration (NASA) manager said on today.

The delay is due to the difficulty of resolving fuel tank problems that triggered the 2003 loss of Columbia and reappeared during the recent Discovery mission.

Engineers resumed work on the shuttle's fuel tank after watching video and pictures of several large pieces of foam flying off the tank as Discovery soared into orbit on July 26.

Unlike the ill-fated Columbia, the foam did not hit Discovery, but NASA grounded the fleet until the tanks are repaired again.

"We didn't find any immediate, easy fixes here," space station programme manager Bill Gerstenmaier, who is overseeing efforts to analyse and resolve the tank problem, said.

"More than likely, we're probably going to have to make some kind of minor engineering modifications to the tank, and to do that, we probably will not make the September launch window," Gerstenmaier said.

NASA had hoped to launch its next shuttle, Atlantis, on a follow-up test flight and servicing mission to the International Space Station in September.

A large chunk of insulating foam fell off Columbia's fuel tank during lift-off and smashed into the orbiter's left wing. When the shuttle attempted to land 16 days later, superheated atmospheric gases blasted into the hole and destroyed the vehicle. The seven astronauts aboard were killed.

NASA spent 2-1/2 years and more than US$1 billion ($1.4 billion) fixing the tank and implementing other safety upgrades after the accident.

Discovery returned from a 14-day flight on Tuesday, the first shuttle mission since the accident.

Five teams are scrutinising records, pictures and other data that document every aspect of the manufacture, processing, shipping and flight preparations of the fuel tank used during Discovery's launch.

Engineers are also using video and pictures taken from dozens of cameras to pinpoint when and where critical pieces of foam broke away during the climb to space.

They expected to spend several more weeks examining five areas of foam loss, the largest of which involved a 450g chunk of hand-sprayed foam from an aerodynamic ramp intended to shelter electrical connections and pipes that run along the outside of the tank.

Gerstenmaier said a routine and minor repair to the ramp may have been a contributing factor to the foam's breaking off during launch but was unlikely to be the sole reason for the failure.

"There's probably another underlying problem," he said.

For the immediate future, NASA is considering removing the ramps and respraying them to assure that there are no hidden defects.

"I don't see a major rework," Gerstenmaier said. "It's essentially subtle, small details that we can correct."

First and foremost, he added, NASA must understand why Discovery's tank shed foam.

"Our plan is going to be to understand what caused this foam shedding and then to remove that cause so that we don't have a large piece of foam coming off the tank," Gerstenmaier said.

- REUTERS