Forecasters are predicting typical summer weather for Wednesday.
CAPE CANAVERAL, Fla. -- For the second time in 10 days, shuttle Atlantis' six astronauts flew into the Kennedy Space Center on Saturday to prepare for a scheduled launch this week.
The countdown toward Wednesday's planned 12:28 p.m. liftoff was set to begin at 8 a.m. today. Forecasters are predicting typical summer weather at Cape Canaveral on launch day: high temperatures in the upper 80s with partly cloudy skies and a 40 percent chance of scattered thunderstorms.
So far, Mother Nature has been uncooperative with NASA's attempts to launch the shuttle on an important 11-day construction mission to the international space station.
The worst lightning strike ever recorded at the launch pad forced shuttle managers to delay Atlantis' flight last week while engineers made sure the ship's systems suffered no damage. And Tropical Storm Ernesto's path prompted NASA officials to roll the shuttle off the pad and halfway to shelter.
Shortly after arriving back at Cape Canaveral, Atlantis commander Brent Jett described how the astronauts saw the shuttle heading to safety as they flew back to their homes in Houston last Tuesday.
"I think all of us thought we were going to be spending a little while in Houston," Jett said. "We're all really happy that just four days later we're back here and we've got a shot at this launch window."
The current window consists of three consecutive launch attempts on Wednesday, Thursday and Friday. After Friday, it is unclear when NASA would have another opportunity.
Atlantis might have to wait until at least Sept. 30 because of a Russian Soyuz mission to the station that is scheduled to lift off Sept. 18 and return from the outpost Sept. 29. However, any shuttle launch between late September and the last week of October would require NASA to waive self-imposed rules requiring this mission to lift off in daylight.
In the wake of the 2003 Columbia accident, mission managers decided to launch the next two flights in daylight to better determine whether changes made to stop debris from coming off the shuttle's external fuel tank were successful. That requirement was extended to the current mission after the tank performed poorly during the shuttle's return to flight in July 2005.
If the restriction isn't waived, Atlantis could have as few as three launch opportunities for the remainder of 2006. The next launch window that meets lighting and other requirements is Oct. 26-27.