Huge clouds roll over Launch Pad 39B where Space Shuttle Atlantis still sits after the scrub of its launch on mission STS-115. Atlantis was originally scheduled to launch at 12:29 p.m. EDT on September 6th, but a 24-hour scrub was called by mission managers due to a concern with fuel cell 1. Towering above the shuttle is the 80-foot lightning mast. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the International Space Station. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA / Ken Thornsley

Space Shuttle Atlantis and the STS-115 crew is set to launch Friday morning on an assembly mission to the International Space Station. The launch time for Atlantis is targeted for 11:41 a.m.

During a Thursday evening news conference Wayne Hale, Space Shuttle Program manager, said the decision to fly came about after a lively and inclusive meeting with space shuttle mission managers and engineers held in the early afternoon. “If you ever wanted to see the difference between the old NASA and the new NASA, you should’ve been over there today. There was a chance for everyone to participate.” Hale continued to say that the Mission Management team’s vote to fly on Friday was nearly unanimous.

The decision to launch follows analysis of an issue found with one of Atlantis’ three electricity-generating fuel cells, which was discovered during pre-launch preparations earlier this week. NASA engineers have determined that any failure of the suspect fuel cell during the mission poses no danger to Atlantis and its crew. They also believe two fuel cells alone would provide Atlantis with enough power to accomplish the major goals of the mission.

The conditions at Kennedy Space Center for Friday’s launch look promising with only a 30 percent chance that weather could ground the flight. The primary weather concerns for the morning launch are of cumulus clouds or isolated thunderstorms in the area.

Source: NASA

NASA TV coverage of tomorrow’s launch attempt begins at 5:30 AM EDT. Complete high-definition coverage starts at 7:00 AM EDT on HDNet, including commentary and analysis provided by Charles D. Gemar, a veteran of three shuttle missions (STS-38, STS-48, and STS-62).

More:

• Live NASA TV Video & Countdown Clock
• NASA’s Launch Blog
• Countdown 101
• Landing 101