Posted: Thu, Sep 7, 2006, 8:26 AM ET (1226 GMT)

NASA shuttle managers decided late Wednesday not to attempt a shuttle launch on Thursday, hoping the extra time would resolve a glitch with a fuel cell and enable a Friday launch. The launch, which had been scheduled for Wednesday, was delayed in the early morning hours after technicians noticed a voltage anomaly with one of the shuttle's three fuel cells. Unable to understand the problem completely during the day, shuttle officials decided late Wednesday to push back the launch a day, believing that should give engineers enough time to determine what caused the voltage spike and certify that the fuel cell is safe to fly as-is. The current launch window for the STS-115 mission closes on Friday, although it may be possible to squeeze in a final launch attempt Saturday without affecting a Soyuz launch to the ISS scheduled for September 18. NASA is also looking into modifying lighting requirements for shuttle launches that could permit another launch attempt in late September.