Procedure of the countdown of the launching of the American space shuttle

The procedure of the countdown of the launching of the American Space shuttle is a long phase of control of all the vital bodies of the launcher (motorization, energy supply and in Comburant S, Communication S, systems of Pilotage and systems of survival) which extends on 3 Jour S.

3 days before launching

Call to the stations of listening;
Beginning of the countdown with T - 43 H;
Beginning of the transfer to the site of shooting and of the last phase of preparation to launching;
Checking of the back-up systems of the systems of flight of the shuttle;
Checking of the software of flight;
Loading of the software of the system of flight in the computers of the shuttle;
Withdrawal of certain bridges;
Beginning of the tests of the navigation system;
T - 27 H: first stop of the countdown for one period of 4:00;
Withdrawal of the launching pad of the personnel nonnecessary;
Test of the pyrotechnic devices of the launcher.

2 days before launching

Taken again countdown;
Beginning of the operations of filling of the tanks of the shuttle (containing hydrocarbon and combustive cryogenic);
T -19 H: second stop of the countdown for one period of 4:00;
Filling of the water tanks present on the launching pad, which will flow at the time it takeoff to attenuate the noise;
Uncoupling of the intermediate umbilical cord;
Taken autonomy of the vehicle and disconnection of its instruments on the ground;
Taken again countdown;
final Preparation of the three principal engines of the shuttle;
Withdrawal of the operating platform;
Stop of the countdown for one 12 hours and 45 minutes period;
Checking of the stellar guidance system;
Activation of the inertial systems of measurement of the shuttle;
Activation of the communication systems of the shuttle.

1 day before launching

Arrangement inside the shuttle of the material of the crew;
Withdrawal of the device of filling at the top of the principal tank (RSS, or Rotating Service Structure);
Reading of the checklist of takeoff;
Purging of the combustion chambers;
Taken again countdown with T - 11:00;
Setting in motion of the petrol stations;
Withdrawal of the zone of danger of the nonessential personnel;
New stop of the countdown with T - 6:00 for one period of 2:00;
Checking of the integrity of the tanks of the shuttle;
Withdrawal of the launching pad of all the personnel;
Refrigeration of the fuel drains;
Beginning of the filling of the external reservoir of the shuttle;
Taken again countdown;
Fine of the filling of the external reservoir;
Inspection of the launching pad;
T-3 H: stop of the countdown for one period of 2:00;
Checking of the communications with `' Align Merritt Island Launch Area'' (MILA), antennas of continuations;
Taken again countdown;
Direction of the crew towards the launching pad;
Checking of the instruments of the cockpit;
Beginning of the installation of the crew on board shuttle;
Checking by the crew of the good performance of the communication systems between the shuttle and the Control center and of launching.

Day of launching

Closing of the hopper of entry of the shuttle;
Test and closing seals hopper of entry;
Fine of the operations in clean room;
Withdrawal of the personnel present in the clean room;
Withdrawal of the last personnel;
Stop of the countdown for 10 m with T - 20;
Last débriefing transmitted to the team of preparation of launching;
Fine of inertial measurements;
Taken again countdown with T - 20 m;
Rocker of the computers of the shuttle in " mode; configuration of lancement" ;
Beginning of the thermal conditioning of the petrol stations;
Closing of the valves of ventilation of the cabin of the shuttle;
Rocker of the systems of flights of help in " mode; configuration of lancement" ;
Stop of the countdown with T - 9 m for one period of approximately 45 m;
Decision on behalf of the director of launching, the team of management of the mission and the director of tests, launching the last phase of the countdown;
Taken again countdown with T - 9 m;
Beginning of the automatic sequence of launching;
T - 7 m 30 S: withdrawal of the arm of access to the crew;
T - 6 m 15 S: beginning of the recording of the mission;
T - 5 m 00 S: startup of the auxiliary generators of power;
T - 5 m 00 S: starting of the engines of booster rockets (SRB) and activation of the safety devices;
T-3 m 55 S: ventilation of the liquid oxygen circuits;
Put in configuration of flight of mobile surfaces of the shuttle;
T - 2 m 55 S: setting under pressure of the liquid oxygen tank;
T - 2 m 50 S: beginning of the withdrawal of the arm of liquid oxygen filling;
T-1 m 57 S: setting under pressure of the liquid hydrogen tank;
T-1 m 00 S: setting not under tension of the heaters of the joints of the booster rockets;
T - 0 m 50 S: powering autonomous of the orbitor;
T - 0 m 31 S: startup of the automatic sequence;
T - 0 m 6,6 S: lighting of the three engines of the shuttle and the principal engine;
T - 0: lighting of the booster rockets and takeoff.
T + 2 m: dropping of the Booster rocket S

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