The space shuttle Discovery is leaking on the launch pad.
If it isn't fixed soon, the small fuel leak could delay Discovery's planned launch on Nov. 1. The flight to the International Space Station is be Discovery's last.
Shuttle engineers met Monday afternoon to put together a repair plan. Later this week, technicians will tighten the bolts on the leaking fuel line. If that resolves the problem, Discovery could still launch on time.
But if that doesn't help, they may have to replace four seals or even part of the line. The leak involves seepage of toxic hydrazine thruster fuel from the plumbing in one of the shuttle's orbital maneuvering system pods, or OMS pods. The OMS thrusters are used during flight for on-orbit course changes.
Last week, NASA replaced a cap in the system, but it did not stop the leak.
The worst-case scenario would involve bringing Discovery back to the Vehicle Assembly Building for more extensive and time-consuming repairs. If the shuttle does not lift off during the first week of November, the mission could be delayed until as late as next February, due to a combination of launch-pad conflicts and orbital constraints.
During its STS-133 mission, Discovery is to deliver a module to orbit for permanent attachment to the space station as an extra storage room. Next Monday, launch managers are due to set the shuttle's official launch date at a flight readiness review.
The shuttle Endeavour is due to take the flight after Discovery's, and one last mission is expected to be flown next summer, using the shuttle Atlantis. Then all three shuttles are to be retired and put in museums. The Smithsonian Institution's National Air and Space Museum has already called dibs on Discovery.
After the shuttle fleet's retirement, the space station is to be resupplied by Russian, European and Japanese transports, as well as commercial U.S. spaceships that are currently under development.
This report includes information from The Associated Press and msnbc.com.