Wednesday's planned launch of space shuttle Discovery on a supply mission to the International Space Station has been delayed by a potential electrical problem, NASA said on Tuesday.
The US space agency had planned the final liftoff of Discovery, which is the first of its three shuttles facing retirement, for 3.52pm EDT (1952 GMT), from the Kennedy Space Center in Florida.
The launch was delayed, however, due to a problem with a backup computer that controls one of Discovery's three main engines, NASA spokesperson Allard Beutel said.
The flight has not yet been rescheduled but NASA has until Sunday or possibly Monday to get Discovery off the launch pad before heating issues, due to the angle of the sun, and previously scheduled activities aboard the space station would force a delay to December.
The next launch opportunity is at 3.29pm EDT (1929 GMT) on Thursday though meteorologists forecast only a 30%chance conditions would be acceptable for liftoff. The outlook for Friday improves with 70% chance weather would be suitable.
Discovery is making its 39th and final flight, with just one or two missions remaining before the entire three-ship shuttle fleet is retired.
The United States is ending the shuttle program in 2011 to put money toward developing spacecraft that can travel deeper into space, with the goal of landing astronauts on an asteroid, and eventually Mars - places beyond where the shuttles can fly.
Discovery's launch was originally planned for Monday but delayed for two days to fix a leak in the system the shuttle uses to maneuver once it is in space.
The mission, the 133rd in the shuttle program, is expected to last 11 days, with the possibility of an additional day being added.
The shuttle will be carrying spare parts, a storage room and a prototype humanoid robot named Robonaut 2 that will live in a US lab aboard the space station. The robot, developed in partnership with General Motors, was designed to assist station crew members with maintenance tasks.
