STS 121 countdown

On approche (J-7)
A noter le dernier paragraphe donnant les horaires de retransmission TV (marquées par *)

COUNTDOWN MILESTONES
*Televised events (times may vary slightly)
All times Eastern

Launch-3 Days (Wednesday, June 28)

Prepare for the start of the STS-121 launch countdown
Perform the call-to-stations (4:30 p.m.)
Countdown begins at the T-43 hour mark (5 p.m.)
Begin final vehicle and facility close-outs for launch
Check out backup flight systems
Review flight software stored in mass memory units and display systems
Load backup flight system software into Discovery's general-purpose
computers

Launch-2 Days (Thursday, June 29)

Remove mid-deck and flight-deck platforms (1 a.m.)
Complete preparation to load power reactant storage and distribution
system (4 a.m.)
Activate and test navigational systems (6 a.m.)
Flight deck preliminary inspections complete (9 a.m.)

Enter first built-in hold at T-27 hours for duration of 4 hours (9
a.m.)

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

Resume countdown (1 p.m.)

Begin operations to load cryogenic reactants into Discovery's fuel
cell storage tanks (2:30 p.m.)

Enter 4-hour built-in hold at T-19 hours (9 p.m.)

Demate orbiter mid-body umbilical unit (9:30 p.m.)
Resume orbiter and ground support equipment closeouts

Launch-1 Day (Friday, June 30)

Resume countdown (1 a.m.)

Final preparations of shuttle's three main engines for main propellant
tanking and flight (1 a.m.)
Begin filling pad sound suppression system water tank (2 a.m.)
Pad sound suppression system water tank filling complete (5 a.m.)
Close out the tail service masts on the mobile launcher platform

Enter planned hold at T-11 hours for 13 hours, 53 minutes (9 a.m.)

Begin star tracker functional checks (9:50 a.m.)
Activate orbiter's inertial measurement units
Activate the orbiter's communications systems
Install film in numerous cameras on the launch pad (10:55 a.m.)
Flight crew equipment late stow (2:50 p.m.)
Move Rotating Service Structure (RSS) to the park position (6:30 p.m.)
Perform ascent switch list
Fuel cell flow-through purge complete

Resume countdown at T-11 hours (10:53 p.m.)

Launch Day (Saturday, July 1)

Activate the orbiter's fuel cells (12:02 a.m.)
Clear the blast danger area of all non-essential personnel
Switch Discovery's purge air to gaseous nitrogen (12:53 a.m.)

Enter planned 2-hour built-in hold at the T-6 hour mark (3:53 a.m.)

Launch team verifies no violations of launch commit criteria prior to
cryogenic loading of the external tank
Clear pad of all personnel

Resume countdown (5:53 a.m.)

Chill down of propellant transfer lines (5:53 a.m.)
Begin loading the external tank with about 500,000 gallons of
cryogenic propellants (about 6:03 a.m.)
Complete filling the external tank with its flight load of liquid
hydrogen and liquid oxygen propellants (about 8:53 a.m.)
Final Inspection Team proceed to launch pad

Enter planned 3-hour built-in hold at T-3 hours (8:53 a.m.)

Perform inertial measurement unit preflight calibration
Align Merritt Island Launch Area (MILA) tracking antennas
Perform open loop test with Eastern Range

Resume countdown at T-3 hours (11:53 a.m.)

Crew departs Operations and Checkout Building for the pad (11:58 a.m.)
Complete closeout preparations in the white room
Check cockpit switch configurations
Flight crew begins entry into the orbiter (about 12:28 p.m.)
Astronauts perform air-to-ground voice checks with Launch and Mission
Control
Begin to close Discovery's crew hatch (about 1:38 p.m.)
Begin Eastern Range final network open loop command checks
Perform hatch seal and cabin leak checks
Complete white room closeout
Closeout 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 (2:33 p.m.)

NASA test director conducts final launch team briefings
Complete inertial measurement unit preflight alignments

Resume countdown at T-20 minutes (2:43 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 estimated 40-minute hold at T-9 minutes (2:54 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 3:40 p.m.)

Start automatic ground launch sequencer (T-9:00 minutes)
Retract orbiter crew access arm (T-7:30)
Start mission recorders (T-6:15)
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 bi-pod heaters (T-1:52)
Deactivate SRB joint heaters (T-0:60 seconds)
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)


SUMMARY OF STS-121 LAUNCH DAY CREW ACTIVITIES

Saturday, July 1
5:15 a.m. - Crew wakes up
*10:10 a.m. - Crew Photo opportunity
10:48 a.m. - Weather briefing (CDR, PLT, MS2)
*11:30 a.m. - Astronauts put on flight suits
*11:58 a.m. - Depart for launch pad
*12:28 p.m. - Arrive at white room and begin to enter Discovery
*1:43 p.m. - Close crew hatch
*3:49 p.m. - Launch

Merci domi :)
nous allons vivre des moments forts !

Je vais tenter l'acquisition DVD du lancement et de l'atterrisage via CNN :)