CAPE CANAVERAL, Fla. - NASA will try today to launch space shuttle Discovery on its final voyage.
Mission managers met Wednesday into the evening to discuss an electrical problem that forced a one-day delay. They concluded the shuttle is safe to fly.
But forecasters say there is an 80 percent chance that thunderstorms will keep Discovery on the pad. Liftoff is scheduled for 3:29 p.m.
The decision came as dark storm clouds rolled over the launch site in Florida.
Managers will reconvene before daybreak to assess the weather, before loading the shuttle's fuel tank.
Discovery's flight to the International Space Station was first stalled by gas leaks. Then a problem cropped up Tuesday with a computerized controller for one of the main engines. At this point, the mission is running three days late.
The space agency has until Sunday, possibly as late as Monday, to launch Discovery. Otherwise, it will have to wait until December because of sun angles.
Aboard Discovery for its 39th and final voyage will be a crew of six as well as thousands of pounds of supplies, including a humanoid robot.
Discovery has carried 180 individuals into orbit over its 26-year career, and logged nearly 150 million miles and more than 5,600 orbits of Earth. It is NASA's oldest surviving shuttle and fleet leader, and will be the first to be prepared for museum retirement.
One final shuttle mission is officially on the books for next year as NASA looks toward newer and farther-flying craft. An extra flight may be added.