NASA’s planned launch of the space shuttle Discovery has been delayed until Wednesday afternoon. This is planned to be Discovery’s last flight.

Leakage was detected during the fueling of Discovery’s helium tanks preflight.  “We had a couple of leaks and we tried to repair those overnight,” Spaulding told reporters Oct. 29th. “We weren’t completely successful in doing so.”  So now NASA will be completely replacing the couplings on the right-hand OMS helium line.  The work is described as being uncomplicated, but time-consuming.

Discovery is now set to launch on Wednesday afternoon, November 3rd, at 3:52 p.m. The shuttle’s mission is a resupply trip to the International Space Station (ISS). The current outlook for Wednesday’s weather is good, according to Kathy Winters, the shuttle weather officer with the U.S. Air Force’s 45th Space Wing Weather Squadron. She said there is a 70% chance of the weather being acceptable for launch on Wednesday afternoon.

NASA will have a four day window to launch Discovery, though on Thursday the weather may worsen. A cold front is expected to move through the area that day, bringing with it low clouds and the possibility of showers and thunderstorms. If Discovery is unable to launch by November 7th, the next launch window will open December 1st.

This is expected to be Discovery’s last flight. After Discovery’s retirement, Endeavor and Atlantis will be the final two shuttles in service. Endeavor is sent for a late February 2011 launch. The Atlantis launch, which is pending congressional budget approval, maybe scheduled for June, 2011.  These are expected to the final missions of NASA’s space shuttle program.