Astronauts say main mission objectives achieved

HOUSTON, July 11 (Reuters) Astronauts on shuttle Discovery today said they had achieved the key goals of their mission and put NASA on the road to recovery from the 2003 Columbia disaster.

Their comments in press interviews from the shuttle came a day after a spacewalk that NASA hailed as a big step toward completing the half-finished, 0 billion International Space Station.

''We were all hoping in NASA for two things to come out of (this flight). The first thing is that the shuttle would fly with no problems, no big dings on ascent ... and we seem to have achieved that,'' said astronaut Piers Sellers.

''The second thing is that we would leave (the space) station in good shape and ready to pick up the assembly sequence,'' he said.

''I think we're there now.'' ''My brother put it very well,'' said shuttle pilot Mike Kelly, recounting a conversation with his twin and fellow astronaut Scott Kelly. ''He said 'We're back, baby.'' Discovery is making only the second shuttle flight since Columbia broke apart while returning to Earth on February 1, 2003. It launched on July 4 from Florida and is scheduled to return on July 17.

Columbia was doomed by fuel tank foam that damaged a wing heat shield at launch, which allowed fiery gases to penetrate and destroy the shuttle as it descended through the atmosphere 16 days later.

NASA, which has made 1.3 billion dollar in safety upgrades, said on Saturday that Discovery came through launch with no major damage and should return safely when it lands next week.

Sellers and Michael Fossum performed a key spacewalk on Monday in which they repaired a space station transport system that can put in place the major segments needed to complete the outpost.

The fix paved the way for an Aug. 28 flight in which shuttle Atlantis will carry a massive solar energy unit to the station to resume construction that NASA halted after Columbia.

NASA hopes to fly 15 more shuttle flights to finish the station before its three-shuttle fleet is retired in 2010.

Failure to make Monday's repair would have been a big setback, NASA officials said.

''If we didn't get this successfully changed, we couldn't proceed with the next mission, which is right on our heels,'' flight director Rick LaBrode said. ''It was a big deal.'' Sellers and Fossum spent today preparing for a Wednesday spacewalk their third and final one of the mission in which they will test materials and techniques to repair damaged heat shields.

Yesterday's walk, Sellers' jet-powered backpack, which would be used to get him back to the space station if he became untethered from it, came loose twice.

''What we think happened is the little latches that protrude a bit got bumped when I was wriggling around in very tight quarters,'' he said.

Sellers said it was likely that the latches, which hold the jet pack on, would be taped down to prevent a recurrence.

REUTERS SY BD2124