This story was updated at 9:57 p.m. ET.
NASA has delayed the launch of space shuttle Discovery's final flight yet again in order to allow more time repair the spacecraft's beleaguered fuel tank, the space agency announced late Thursday (Jan. 6).
The decision came after a meeting of top space shuttle program managers earlier in the day to evaluate the progress of Discovery's fuel tank repairs. From their analysis, the officials opted to push the next launch attempt further back from the previously scheduled Feb. 3 liftoff.
"There is no official target launch date right now," NASA spokesman Kyle Herring, of the Johnson Space Center in Houston, told SPACE.com. "I would only characterize as late February as the next opportunity."
NASA officials said that with the continuing repairs under way on the external tank, and the potential for additional work still to be defined, it was clear that Discovery would not be ready for flight in time for the early February window, which runs from Feb. 3 to Feb. 10. [Infographic: NASA's Space Shuttles: Top to Bottom]
Shuttle officials want to be sure Discovery's 15-story external tank is structurally sound for launch and won't pose a debris risk to the shuttle during liftoff, Herring said.
Preventing damage from fuel tank foam insulation shaken loose during launch has been a chief concern for NASA's shuttle flights since 2003, when debris hit the shuttle Columbia's left wing during liftoff and ultimately led the loss of the spacecraft and its seven astronaut crew as they were re-entering the atmosphere ahead of landing.
More shuttle delays
Discovery's final mission – a delivery run to the International Space Station – has been delayed since early November due to external fuel tank cracks and other issues.
New launch targets for Discovery's STS-133 mission, and subsequently for the shuttle Endeavour's STS-134 mission, will be discussed next Thursday (Jan. 13) at the weekly meeting for top shuttle program managers.
According to some news reports, the next available launch window extends from Feb. 27 to March 6. But Herring said the late February launch window is still under review.
One wrinkle in launch planning for Discovery is traffic bound for the International Space Station, where the shuttle is also headed. Cargo ships from Japan, Europe and Russia are all due to visit the station over the next few months, so Discovery's last mission will have to be wedged somewhere in between.
"All of that is going to happen in the next several weeks, and that has to be factored in," Herring said on the station's busy space traffic schedule.