Shuttle Discovery Moves Closer Towards July Launch

Discovery’s rollover to the VAB marks the start of the journey to the launch pad and, ultimately, launch. Once inside the VAB, Discovery will be raised to vertical and lifted up and over into high bay 3 for stacking with its redesigned external tank and twin solid rocket boosters. CREDIT: NASA/Jim Grossmann.

CAPE CANAVERAL, Fla. - NASA's space shuttle Discovery moved a step closer towards its planned July launch Friday as engineers delivered the orbiter to be mated to its fuel tank and rocket boosters.

Discovery rolled into NASA's 52-story Vehicle Assembly Building (VAB) here at the agency's Kennedy Space Center at about 12:14 p.m. EDT (1612 GMT), where it will be readied to fly the second shuttle flight since the 2003 Columbia accident.

"Of course we're very excited," said Stephanie Stilson, NASA's flow manager for the Discovery orbiter, after the spacecraft reached the VAB. "We couldn't ask for a nicer day today to be rolling over."

Discovery is slated to launch six shuttle astronauts and one space station crewmember to the International Space Station (ISS) in early July during NASA's STS-121 mission. The space agency hopes to launch the orbiter by July 1, but has until July 19 to make the space shot.

"It's awesome that we're getting back to flight again," said Ken Revay, manager of external tank and solid rocket booster operations for NASA contractor United Space Alliance, in an interview. "That's what the team is put together to go do, and we have the best in the world."

But Discovery's road to the VAB has been long. The spacecraft returned to KSC from California's Edwards Air Force Base - where it landed after NASA's first post-Columbia mission STS-114 - on Aug. 21, 2005, and spent months inside its hangar-like Orbiter Processing Facility undergoing work for the next flight.

Engineers replaced seven of the Discovery's 10 cockpit windows and changed out 5,104 of the 15,000 gap-fillers between the thousands of heat-resistant tiles that line the orbiter's underbelly. The measure, NASA hopes, will prevent gap-fillers from jutting out during flight and adding a potential heat source during reentry.

STS-114 spacewalker Stephen Robinson physically removed two such protruding gap-fillers during the last shuttle flight.

Shuttle workers also had to repair the shuttle's robotic arm, which was damaged during a string of accidents that led KSC officials to call a work timeout to refocus efforts to ensure worker and hardware safety.

"Every person that works on this vehicle has accountability," Stilson said, adding that the prolonged period between shuttle flights since the Columbia accident may have left some workers rusty. "Anytime we have anything doesn't go the way we expect, we all feel it."

Stilson said very little work remains for Discovery, which is on track to roll out to NASA's Pad 39B launch site in the early hours of May 19.

"The next thing we're looking forward to is getting out to the pad," Stilson said.

Discovery's STS-121 spaceflight will mark NASA's last test flight to check shuttle safety, repair and inspection improvements before resuming ISS construction.

The launch will also test the orbiter's redesigned external tank, which has been stripped of a foam ramp to reduce the amount of potentially harmful debris during launch and ascent. Foam debris at launch pierced Columbia's heat shield, dooming the orbiter and its seven astronauts during reentry on Feb. 1, 2003.

• NASA Pushes Shuttle Discovery's Move to Friday
• Return to Flight: NASA's Road to STS-121