US space shuttle Discovery is leaking on its launch pad in Florida.
If it is not fixed soon, the small fuel leak could delay Discovery's planned launch on November 1 at Cape Canaveral.
The flight to the International Space Station will be Discovery's last.
Shuttle engineers met on Monday afternoon to put together a repair plan. Later this week, technicians will tighten the bolts on the leaking fuel line.
If that does not help, they may have to replace four seals or even part of the line.
Last week, Nasa replaced a cap in the system, but it did not stop the leak.
The rocket fuel is used to manoeuvre the shuttle while it is in orbit.