NASA has set Space Shuttle Atlantis’ launch for Friday, Sept. 8, at 11:41 a.m. EDT. Shuttle program managers made the lift-off decision after reviewing more detailed data on a problem associated with one of the spacecraft’s electricity-producing fuel cells.

Mission managers will review an additional piece of analysis before the shuttle’s external fuel tank is loaded at 1:45 a.m. EDT. Shuttle Program Manager Wayne Hale said he was confident the results of the analysis would support the launch decision.

Tuesday night as ground teams were preparing for a scheduled Wednesday launch attempt, a voltage spike in the motor of Atlantis’ fuel cell #1 coolant pump was observed during the activation of the shuttle’s three fuel cells. The coolant pump circulates Freon through the fuel cell to prevent it from overheating during flights.

If Friday’s launch is delayed, there could be another attempt Saturday at 11:15 a.m. EDT.

During Atlantis’ mission, STS-115, astronauts will deliver and install the P3/P4 truss, a girder-like structure, with solar arrays that will double the International Space Station’s power capability.

Atlantis’ crew consists of Commander Brent Jett, Pilot Chris Ferguson and mission specialists Dan Burbank, Heide Stefanyshyn-Piper, Joe Tanner and Steve MacLean, a Canadian Space Agency astronaut.

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