All members of the launch team report to their respective consoles in the Firing Room of the Launch Control Center for the start of the countdown. The space shuttle vehicle is powered up and back up flight systems are checked out. Flight software is reviewed and NASA personnel begin to stow flight crew equipment aboard the orbiter. The launch pad is cleared of all non-essential personnel.
Personnel begin to load cryogenic reactants into the shuttle's fuel cell storage tanks.
Final preparations of the shuttle's three main engines for main propellant tanking and flight get underway. The orbiter's flight controls and navigational and communications systems are activated. Film is installed in numerous cameras on the launch pad and the sound suppression system water tank is filled. NASA's Shuttle Launch Countdown Homepage is the gateway to a variety of useful information relating to space shuttle launches, processing, countdown and status.