Qa'dah 21, 1431 H/Oct 29, 2010, SPA -- The launch of the U.S. space shuttle Discovery on a mission to deliver a storage module and supplies to the International Space Station is being delayed until Tuesday because of a helium leak in the shuttle's on board steering system, Reuters quoted officials as saying on Friday. The U.S. space agency NASA had been planning to begin the three-day launch countdown on Friday, leading to an originally scheduled liftoff on Monday afternoon. The flight, one of the last of the shuttle program, was rescheduled for launch at 4:17 p.m. EDT (2017 GMT) on Tuesday. Technicians discovered the leak late on Thursday as they were pressurizing tanks that are part of the shuttle's space maneuvering systems. A helium line unexpectedly vented, leading workers to a coupling connecting ground support equipment to the flight hardware. Inside, they found a ring which had come off a seal. They removed it, but that failed to fix the leak. Managers then decided to replace both ground and flight couplings, work that will stall other launch preparations to the point of not being able to make Monday's launch window. A second small leak in a nitrogen line, used for pressurization, would also be fixed, said NASA test director Jeff Spaulding. Meteorologists predicted a 70 percent chance that the weather would be suitable for launch on Tuesday, shuttle weather officer Kathy Winters said. One or two further shuttle missions remain before the program ends. The shuttles began flying in 1981. They are being retired due to high operational costs of about $3 billion a year, ongoing safety concerns, and a shift in U.S. policy towards flying astronauts beyond the vicinity of Earth into deep space, where the shuttles cannot travel. The space station, a $100 billion project of 16 nations, orbits about 220 miles (352 km) above Earth. The storage module being carried aboard Discovery is the last addition to the U.S. side of the outpost, which has been under construction since 1998. NASA plans to fly the $2 billion Alpha Magnetic Spectrometer particle detector to the station in February and possibly make a final supply run with shuttle Atlantis next June or July.
