NASA Finds Fuel Leak on Space Shuttle Discovery
Space shuttle Discovery is the oldest in NASA's fleet, but will be the first to retire after one final spaceflight. NASA pulled out all the stops Sept. 20, 2010, when Discovery made its last trip to the launch pad for its final flight. The shuttle is due to launch Nov. 1, 2010.
Credit: NASA/Jack Pfaller

The space shuttle Discovery has developed a small fuel leak while on the launch pad, with NASA engineers working to make repairs in time for the spacecraft's final launch on Nov. 1.

The leak was discovered in an aft compartment on the space shuttle where two propellant lines converge to feed Discovery's two orbital maneuvering system engines. It must be repaired soon if Discovery is to make its scheduled launch from NASA's Kennedy Space Center in Cape Canaveral, Fla.

Engineers spotted the leak when they noticed that some of Discovery's insulating blankets covering a seal in the area were damp with monomethyl hydrazine, one of two chemicals used to ignite the engines located on either side of shuttle's tail, NASA officials said. [Photos: Discovery's Launch Pad Trip]

"It?s clearly a very toxic chemical, so a lot of precautions have to be taken even with a very small leak like this," NASA spokesman Allard Beutel told SPACE.com.

Beutel said shuttle engineers plan to tighten six bolts around the flange seal to stop the leak. If that doesn't solve the problem, technicians wearing bulky hazmat suits can try to replace two seals in the system.

"The processing schedule could allow the two seals to be replaced without delaying Discovery's targeted launch on Nov. 1," NASA officials said in an update.

Beutel said NASA currently has four days of padding in its schedule to repair Discovery in time for its upcoming launch.

Discovery's twin orbital maneuvering system engines are vital for the shuttle's mission. They are used for major course corrections while the shuttle is in orbit, as well as to begin the descent back to Earth.

"Specifically, we use these engines to drop out of orbit at the end of the mission," Beutel said.

Discovery also has three main engines, located below its orbital maneuvering system pods, which help launch the shuttle into orbit.

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 last spaceflight 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 is slated to fly the last scheduled mission in early 2011. A third, extra shuttle mission has been approved by Congress and President Obama and is due to be reviewed by congressional appropriators later this year.