By Irene Klotz
CAPE CANAVERAL, Florida (Reuters) - NASA will suspend flights of its space shuttle fleet until it understands why strips of insulating foam peeled off the fuel tank used by shuttle Endeavour, officials said on Thursday.
Endeavour arrived safely in orbit after Wednesday's liftoff from the Kennedy Space Centre in Florida though video and images of the launch showed about a dozen pieces of debris flying off the fuel tank during the 8.5-minute climb to orbit.
Some smashed into the ship's heat shield, though NASA does not believe they caused any serious damage
"We're not worried about this one, but we need to understand what's going on for the next flight," said shuttle program manager John Shannon.
NASA has seven more shuttle launches planned to complete construction of the International Space Station. Its next flight is targeted for launch on August 18.
NASA has been concerned about foam shedding from the tank since losing shuttle Columbia in 2003. A debris impact during Columbia's launch breached the ship's heat shield, which caused Columbia to break apart as it flew through the atmosphere for landing. Seven astronauts died in the accident.
NASA redesigned the tanks to stem foam loss and implemented new procedures and equipment to check for damage after launch.
The images of Endeavour's launch showed strips of foam peeling away from a part of the tank that previously had not been a problem, Shannon said.
The foam loss occurred relatively late during Endeavour's climb to orbit so that there was not much atmospheric force to slam debris into the ship and cause damage. If the foam had fallen off earlier during ascent, it could have been another story.
ENDEAVOUR APPARENTLY UNSCATHED
"It did not hurt on this flight because it came off so late, but we need to understand it before the next flight," Shannon told reporters.
"There's nothing that we have seen on the orbiter that causes us any concern," he added, saying preliminary and still incomplete inspections of Endeavour's heat shield had revealed just a few minor dings.
A variety of tests are planned to determine if the problem on Endeavour's tank was an isolated incident or if there is a more generic issue.
"This is new," Shannon said. "I don't know if we have a material issue or a process issue but we'll get to the bottom of it and clear before the August flight."
The Endeavour astronauts, meanwhile, used the shuttle's robot arm to scan their ship's wings and nose cap with a sophisticated imaging system mounted on the end of a 50-foot (15-metre) boom. The pictures will be analyzed by engineers on the ground over the next several days.
Another key inspection is scheduled for Friday before the shuttle docks at the International Space Station. Commander Mark Polansky will backflip Endeavour so astronauts aboard the station can photograph its heat-resistant belly tiles. Those images also will be relayed to the ground for analysis.
The shuttle, which is carrying the last piece of Japan's Kibo laboratory, is scheduled to spend 11 days at the outpost. Endeavour also is carrying supplies, spare parts and a new station crewmember, U.S. astronaut Timothy Kopra, who will replace Japan's Koichi Wakata as one of the live-aboard flight engineers.
(Editing by Tom Brown and Doina Chiacu)
