From Florida Today
Five days before Discovery’s pre-dawn Monday liftoff to the International Space Station, launch pad 39A is clear of non-essential personnel as the orbiter’s main propulsion system and orbital engines and jets are pressurized for flight.
The hazardous operation was delayed about 12 hours Tuesday to adjust oxidizer temperatures that had dipped too low, but Kennedy Space Center officials say it had no impact on Discovery’s planned 6:21 a.m. launch — possibly the last nighttime shuttle launch.
The shuttle’s seven-person crew, led by commander Alan Poindexter, is shifting its sleep schedules to adjust to the 13-day mission’s overnight work hours. The crew will wake up around 6 p.m. today, do some launch simulations and then fly from Houston into KSC around 7 a.m. Thursday.
Also Thursday, Discovery’s payload bay doors will be closed for flight around the Italian-built cargo carrier Leonardo, which holds roughly 17,000 pounds of science experiments, equipment and supplies.
In front of it in the payload bay is another carrier holding a coolant tank that spacewalkers will install on the station’s structural backbone, replacing another that will be brought home.
Launch managers plan to hold the first countdown status briefing Thursday at 10 a.m., which will provide the first official weather forecasts for Sunday evening fueling operations and Monday’s 10-minute launch window. You can watch the briefing live here by clicking on the NASA TV box at right to launch a video player.
KSC countdown clocks should begin ticking at 3 a.m. Friday.