NASA safety chief won't appeal shuttle launch order

CAPE CANAVERAL, Fla, June 22 (Reuters) NASA's top safety officer has said he won't appeal a decision to clear shuttle Discovery for liftoff next week, even though he has nagging concerns about the spaceship's safety.

On Saturday, following a two-day flight review, NASA safety chief Bryan O'Connor and chief engineer Chris Scolese declined to endorse the U S space agency's certification that Discovery was ready for launch.

At issue is whether additional modifications to the shuttle's external fuel tank were necessary before flights resume. NASA redesigned the tank after the 2003 Columbia disaster, and then again after the first-post Columbia mission last July. Both times large pieces of insulating foam fell off the tank.

Columbia was hit and damaged by the falling debris, triggering the ship's breakup as it flew through the atmosphere for landing.

Seven astronauts died in the accident.

Discovery escaped impact from the falling foam debris during its launch nearly a year ago, but NASA suspended flights for additional modifications.

Some engineers say the agency has not gone far enough, an opinion clearly shared by O'Connor and Scolese. But both, speaking in a teleconference with reporters yesterday, ruled out any last-minute appeals aimed at scuttling the planned July 1 launch of Discovery.

O'Connor said the objections aired over the weekend were only meant to serve formal notice about what he and Scolese see as serious safety concerns. He said NASA Administrator Michael Griffin would have cancelled the flight himself if it posed some undue risk to the shuttle crew, however.

''At this point, it's a done deal,'' said O'Connor. ''We now go forward and we look to see if we can get this vehicle off the launch pad next week.

Since the Columbia accident, NASA has set up a safe haven for shuttle astronauts aboard the International Space Station should their vehicle become too damaged to safely return to Earth.

Post-Columbia safety upgrades also include sophisticated sensors for inflight inspections for damage and rudimentary heat shield repair kits.

NASA Associate Administrator Bill Gerstenmaier stressed, meanwhile, that information collected during Discovery's launch will help engineers develop a better fix for the remaining problem areas of the fuel tank.

REUTERS VJ BST0452