Shuttle tank delays push back Hubble mission

By Irene Klotz

HOUSTON (Reuters) - Delays in producing space shuttle fuel tanks, which were substantially redesigned after the 2003 Columbia disaster, will postpone NASA's final servicing mission to the Hubble Space Telescope by a month or longer, officials at the U.S. space agency said on Thursday.

Originally due to launch on Aug. 28, the space shuttle flight to the telescope will be postponed four to five weeks, shuttle program manager John Shannon said.

"We cannot make the Aug. 28 date," he said during media briefings at the Johnson Space Center in Houston.

To fly to Hubble, NASA decided it needed a second shuttle ready to launch in case the ship carrying the crew became too damaged to return home.

Other missions don't require a backup shuttle because stranded astronauts can take shelter in the International Space Station. The orbital outpost will be too far away for the Hubble crew to reach, however.

Needing two tanks ready for launch strained the manufacturing process, Shannon said, adding that it took time for the agency's contractors to learn new assembly procedures following the 2003 Columbia accident.

NASA suspended tank production and grounded its remaining shuttles to investigate why a piece of insulation foam that fell off Columbia's fuel tank during launch triggered the fatal accident.

Investigators determined the debris had hit a heat panel on Columbia's wing, damaging it and allowing superheated gases to flow inside the structure during atmospheric re-entry.