NASA engineers are replacing fuel line seals on the Space Shuttle Discovery to staunch a small leak in time for the spacecraft’s final blastoff on Nov. 1.

Shuttle technicians are replacing two suspect seals in a fuel line for the twin orbital maneuvering system engines near Discovery’s tail. The repairs should be complete by Oct. 25, just one week before Discovery is due to launch on its last spaceflight from a seaside pad at NASA’s Kennedy Space Center in Cape Canaveral, Fla.

The minor shuttle fuel leak was found in a rear compartment on the shuttle where two propellant lines converge to feed the vehicle’s aft-mounted engines.

During the week of Oct. 18, technicians tightened six bolts on a flange near the seals and saw the leak stop. But NASA wants to be sure there are no issues with the fuel line or seals for Discovery’s upcoming launch.

“Replacing the seals allows NASA managers to have the highest confidence in the system and will allow the seals and flange to be inspected,” NASA officials said in an update.

To replace the seals and flange, engineers must remove the monomethyl hydrazine propellant used in Discovery’s orbital maneuvering system engines from nearby tanks. Those tanks will have to be topped off once the work is complete.

Astronauts use the two orbital maneuvering system engines on Discovery to make major course adjustments in orbit, as well as to begin the descent maneuver to leave orbit and return to Earth, NASA officials have said.

The engines are mounted at Discovery’s rear, one on either side of the shuttle’s tail. They are above the space shuttle’s three main engines, which are used during launch.

If all goes well, the repairs should be completed in plenty of time “to still support Discovery’s targeted Nov. 1 launch date,” NASA officials said.

Discovery is poised to launch on an 11-day mission to deliver a storage room and humanoid robot to the international space station. The mission will be the 39th and last space voyage for Discovery — NASA’s oldest shuttle — and is one of the two missions scheduled before NASA retires its shuttle fleet next year.

The shuttle Endeavour will follow Discovery’s final flight with one last mission of its own in early 2011. A third, extra shuttle mission has been approved by Congress and President Barack Obama but awaits a funding decision by congressional appropriators.

Top NASA shuttle program managers plan to meet Monday for a standard preflight meeting to decide whether Discovery is ready for launch.

The shuttle is currently slated to launch Nov. 1 at 4:40 p.m. EDT. Two spacewalks are planned during the flight. The mission will be NASA’s 133rd shuttle flight since the orbiter fleet began flying in April 1981.