STS-133 Shuttle Discovery's launch delayed

Work to repair the shuttle Discovery's external tank is going well, but more time is needed to complete an engineering review and to develop the necessary flight rationale, the justification for launching with a repaired tank after unexpected damage. As a result, NASA announced Thursday, the flight will remain on hold until at least Dec. 3, four days after the opening of a short end-of-year launch window.

If Discovery is eventually cleared for launch, countdown clocks would begin ticking around 06:00 GMT on November 30, setting up a launch attempt at 07:51:59 GMT on December 3. But officials cautioned that's a "no-earlier-than" launch target and if additional tests are needed, or if unexpected problems develop, the 133rd shuttle mission will remain on hold.

STS-133 Discovery's 39th and final mission

The next shuttle launch window closes December 6. If mission managers give up the possibility of an additional day in orbit, a launch on December 7 would be possible. The next confirmed shuttle launch window opens at the end of February.

Trying to get off on its 39th and final mission, Discovery was grounded November 5 when sensors detected a major gaseous hydrogen leak near a 7-inch vent line quick-disconnect fitting on the side of the ship's external tank. After the countdown was called off, engineers discovered a large crack in the tank's foam insulation near the top of the ribbed intertank section that separates the hydrogen and oxygen tanks.

At that time, launch was put on hold, delayed until at least November 30, the opening of the next available launch window.