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Space Shuttle Countdown to Launch

COUNTDOWN MILESTONES. All times are Eastern. test

Launch - 3 Days

  • Prepare for the start of the STS-80 launch countdown
  • Perform the call-to-stations (12:30 p.m. Tuesday, Nov. 12)
  • All members of the launch team report to their respective consoles in Firing Room 3 in the Launch Control Center for the start of the countdown.
  • Countdown begins at the T-43 hour mark (1 p.m.)
  • Start preparations for servicing fuel cell storage tanks
  • Begin final vehicle and facility close-outs for launch
  • Check out back-up flight systems
  • Review flight software stored in mass memory units and display systems
  • Load backup flight system software into Columbia's general purpose computers
  • Begin stowage of flight crew equipment
  • Inspect the orbiter's mid-deck and flight-deck and remove crew module platforms

Launch - 2 Days

  • Close payload bay doors for flight (about 2 a.m.)

Enter first planned built-in hold at T-27 hours for duration of four hours (5 a.m.)

  • Clear launch pad of all non-essential personnel
  • Perform test of the vehicle's pyrotechnic initiator controllers

Resume countdown (9 a.m.)

  • Clear launch pad of all personnel
  • Begin operations to load cryogenic reactants into Columbia's fuel cell storage tanks (9:30 a.m. - 7 p.m.)
  • Enter eight-hour built-in hold at T-19 hours (5 p.m.)
  • After cryogenic loading operations, re-open the pad
  • Resume orbiter and ground support equipment close-outs

Launch - 1 Day

  • Resume countdown (1 a.m.)
  • Start final preparations of the Shuttle's three main engines for main propellant tanking and flight
  • Activate the orbiter's flight controls and navigation systems
  • Install mission specialists' seats in crew cabin
  • Close-out the tail service masts on the mobile launcher platform

Enter planned hold at T-11 hours for 15 hours, 30 minutes (9 a.m.)

  • Complete off-load of extra cryogenic reactants from service tanks
  • Demate orbiter mid-body umbilical unit and retract into fixed service structure
  • Perform orbiter ascent switch list in crew cabin Install film in numerous cameras on the launch pad
  • Activate the orbiter's communications systems and begin initial voice checks
  • Activate orbiter's inertial measurement units
  • Fill pad sound suppression system water tank
  • Safety personnel conduct debris walkdown
  • Move Rotating Service Structure (RSS) to the park position (8 p.m.)
  • Following the RSS move, begin final stowage of mid-deck experiments and flight crew equipment

Launch Day

Resume countdown (12:30 a.m.)

  • Continue installation of time critical flight crew equipment
  • Perform pre-ingress switch list
  • Start fuel cell flow-through purge
  • Activate the orbiter's fuel cells
  • Configure communications at Mission Control, Houston, for launch
  • Clear the blast danger area of all non-essential personnel
  • Switch Columbia's purge air to gaseous nitrogen

Enter planned one-hour built-in hold at the T- 6 hour mark (5:30 a.m.)

  • Launch team verifies no violations of launch commit criteria prior to cryogenic loading of the external tank
  • Clear pad of all personnel
  • Begin loading the external tank with about 500,000 gallons of cryogenic propellants (about 5:45 a.m.)

Resume countdown (6:30 a.m.)

  • Complete filling the external tank with its flight load of liquid hydrogen and liquid oxygen propellants (about 8:45 a.m.)
  • Perform inertial measurement unit preflight calibration
  • Align Merritt Island Launch Area (MILA) tracking antennas
  • Perform open loop test with Eastern Range
  • Conduct gimbal profile checks of orbital maneuvering system engines

Enter two-hour hold at T-3 hours (9:30 a.m.)

  • Close-out crew and Final Inspection Team proceeds to Launch Pad 39B

Resume countdown at T-3 hours (11:30 a.m.)

  • Crew departs Operations and Checkout Building for the pad (about 11:35 a.m.)
  • Complete close-out preparations in the white room
  • Check cockpit switch configurations
  • Flight crew begins entry into the orbiter (about 12:05 p.m.)
  • Astronauts perform air-to-ground voice checks with Launch Control and Mission Control
  • Close Columbia's crew hatch (about 1:20 p.m.)
  • Begin Eastern Range final network open loop command checks
  • Perform hatch seal and cabin leak checks
  • Complete white room close-out
  • Close-out crew moves to fallback area
  • Primary ascent guidance data is transferred to the backup flight system

Enter planned 10-minute hold at T-20 minutes (2:10 p.m.)

  • NASA Test Director conducts final launch team briefings

Resume countdown (2:20 p.m.)

  • Transition the orbiter's onboard computers to launch configuration
  • Start fuel cell thermal conditioning
  • Close orbiter cabin vent valves
  • Transition backup flight system to launch configuration

Enter 10-minute hold at T-9 minutes (2:31 p.m.)

  • Launch Director, Mission Management Team and NASA Test Director conduct final polls for go/no go to launch

Resume countdown at T-9 minutes (about 2:41 p.m.)

  • Start automatic ground launch sequencer (T-9:00 minutes)
  • Retract orbiter crew access arm (T-7:30)
  • Start mission recorders (T-5:30)
  • Start Auxiliary Power Units (T-5:00)
  • Arm SRB and ET range safety safe and arm devices (T-5:00)
  • Start liquid oxygen drainback (T-4:55)
  • Start orbiter aerosurface profile test (T-3:55)
  • Start main engine gimbal profile test (T-3:30)
  • Pressurize liquid oxygen tank (T-2:55)
  • Begin retraction of the gaseous oxygen vent arm (T-2:55)
  • Fuel cells to internal reactants (T-2:35)
  • Pressurize liquid hydrogen tank (T-1:57)
  • Deactivate SRB joint heaters (T-1:00)
  • Orbiter transfers from ground to internal power (T-0:50 seconds)
  • Ground Launch Sequencer go for auto sequence start (T-0:31 seconds)
  • SRB gimbal profile (T-0:21 seconds)
  • Ignition of three Space Shuttle main engines (T-6.6 seconds)
  • SRB ignition and liftoff (T-0)