NASA said there is a high probability of sending its shuttle Discovery to the international space station on Sunday after delaying it for over a month while they fixed a fuel leak.

Half a dozen NASA engineers worked to fix the gas leak on Friday at the launch pad, putting in a new hydrogen vent line hookup and fresh seals after Wednesday's failed launch attempt.

At a news conference Friday morning, NASA weather officer Kathy Winters said there's an 80 percent chance that weather conditions at the launch site will be acceptable Sunday. The weather is expected to worsen on Monday and Tuesday.

Discovery is set to launch from the Kennedy Space Center in Florida at 7:43 p.m. Sunday. If the launch happens on Sunday, then the mission will be reduced to 13 days and there will be three spacewalks instead of the planned four.

The next mission will be a Russian Soyuz spacecraft that will blast off on March 26. The Soyuz is a higher-priority mission and it will deliver a new crew to the space station.