Space shuttle launch countdown

The following are the main tasks that had to be performed during a countdown for a launch of the Space Shuttle, listed with the associated phase and approximate duration.

Preparations

Preparations for a shuttle flight began with the backup of the orbiter and the need to return to Kennedy Space Center should the previous landing elsewhere, be carried out for example at the Edwards Air Force Base. He was then placed in an Orbiter Processing Facility (OPF ).

Two to three months before the start of the assembly of the space shuttle system began with the assembly of the two solid rocket on a launch platform in the Vehicle Assembly Building ( VAB). Thereafter, the External Tank between the solid rocket was launched and fixed in position.

About five weeks before the start of the orbiter from the OPF was rolled into the VAB and mounted on the external tank. Around the same time the payloads were run for the payload bay to the launch. About one month before the start was the rollout of the Space Shuttle to the launch pad. There, most payloads and equipment were brought to the Orbiter during the following three weeks. One day before the start of the countdown arrived, the crew at the Kennedy Space Center. After a Call to Stations of the test conductor, the countdown clock has started.

Countdown

T -41 hours and counting

The phase lasted 16 hours. (Time to start L -69: 10 h )

  • The last vehicle and building hedges were initiated.
  • The backup flight system was checked.
  • The flight software in main memory, and the displays were reviewed.
  • The backup flight system software was loaded onto the host computer.
  • The working platforms in flight and middle deck have been removed.
  • The navigation system has been activated and tested.
  • The preparation of the power distribution system has been completed.
  • The preparations for the flight deck inspections have been completed.

T- 27 hours and holding

The phase lasted 4 hours (L -53: 10 h ).

  • The staff no longer needed left the launch pad.

T- 27 hours and counting

The phase lasted eight hours ( L- 49: 10 h).

  • The loading of the storage tank for the OMS engines began.

T -19 hours and holding

The phase lasted 4 hours (L -41: 10 h ).

  • Some stands in the middle part of the shuttles were dismantled.

T -19 hours and counting

The phase lasted 8 hours ( L -37: 10 h ).

  • The main engines were prepared for fueling and flight.
  • The sound Eindämmsystem was filled with water.
  • The orbiter and ground support equipment were tested.
  • Several masts on the mobile launcher platform were stowed.

T-11 hours and holding

The period lasted up to 13 hours ( L-29: 10 h ).

  • Last crew equipment was stowed.
  • The RSS - maintenance platform ( Rotating Service Structure) was moved to the park position.
  • The orbi terin internal metering and communication systems were activated.
  • The cockpit was configured to start.

T-11 hours and counting

The phase lasted 5 hours ( L -16: 10 h).

  • The tanks of the orbiter were activated.
  • The staff unneeded left the danger zone.
  • The air of the orbiter was replaced by nitrogen to clean.

T- 6 hours and holding

The phase lasted two hours (L -11: 10 h).

  • The starting team confirmed that there are no problems with the start criteria before the outer tank has been filled.
  • The entire staff left the launch pad.
  • The transfer lines for the fuels were prepared and cooled down.
  • The outer tank was charged with two million liters of liquid fuel ( hydrogen and oxygen).

T- 6 hours and counting

The phase lasted three hours (L -9: 10 h).

  • The filling of the outer tank was completed.

T- 3 hours and holding

The phase lasts 2 hours ( L-6: 10 h ).

  • The measuring units are calibrated for the pre- flight phase.
  • The Merritt - Iceland - tracking antenna was aligned.
  • A team inspected a final time the shuttle from the outside.
  • The Closeout Crew, which is responsible for the safe entry of the astronauts and the closing of the access hatch, went to the launch pad to prepare the orbiter and the White Room for astronaut.

T- 3 hours and counting

Phase took 2 hours and 40 minutes (L -4: 10 h).

  • The crew went to the launch pad and climbed over the White Room in the orbiter one.
  • The preparations for the closing of the orbiter to ran.
  • The switch settings in the cockpit have been checked.
  • The astronauts led by Comchecks with the launch, mission, and possibly other control centers.
  • The orbiter was closed and checked the hatch for leaks.
  • The White Room was saved and exited.
  • The closeout crew went into a relapse area to respond in the event of a crash quickly.

T-20 minutes and holding

Phase lasted for 10 minutes ( L-1: 30 h).

  • The shuttle test director informed the last time the launch team.
  • The measurement unit calibrations have been completed.

T-20 minutes and counting

Phase lasted 11 minutes ( L-1: 20 h).

  • The Orbitercomputer were configured to start.
  • The fuel supply was regulated.
  • The exhaust valves of the cabin crew were closed.
  • The backup flight system has been prepared for the start.

T-9 minutes and holding

The duration of this phase depended on the mission from, but it was about an hour (L -1: 09 h).

  • The flight and start Directors questioned the readiness of their teams to start from ( GO-/NO-GO-Umfrage ).

T-9 minutes and counting

The phase took 9 minutes ( L- 0: 09 h).

  • The automatic ground launch sequencer is started.
  • The actuator for the orbiter was at T- 7 collapsed 30 minutes.
  • The power supply started at T -5: 00 minutes.
  • The target area of the SRBs has been saved.
  • The air surface profile tests and the tests of the moving SSMEs started at T-3: 55 minutes.
  • The Gasabluftarm was at T -2: 55 caught up.
  • The crew completed their visors for T-2: 00 minutes.
  • The orbiter was switched at T -55 seconds from ground to internal power supply.
  • At T -31 seconds, automatic start sequencer got the GO to start. Up to this time the countdown was stopped and canceled by the start control, then the reset could be prevented only by an automatic shutdown of the main engines.
  • The acoustic insulation system was activated at T -16 seconds, and sprayed more than 1 million liters of water in 41 seconds under the engines to prevent damage caused by sound waves.
  • At T -10 seconds, the burn- off system sparks began to spray.
  • The main engines participated in the T-6, 6 seconds for their work.

T-0

  • The two solid rocket boosters were ignited and the Space Shuttle takes off.

After the start

  • Mission control took over the flight after the spacecraft left the launch tower.
  • The roll maneuver, which hosted the shuttle for the planned orbit, was also performed shortly after leaving the starting tower.
  • The SRBs were jettisoned two minutes after launch. They were later recovered from the Atlantic.
  • About eight minutes after launch, the main engines were shut down.
  • Ten seconds later, the external tank was dropped.
  • The crew received the GO for on-orbit activities.
  • OMS engines were first fired to achieve a stable orbit.
  • 1.5 hours after the start of the charging doors were opened.
  • Six hours after the start of the Orbiter was fully airworthy, the SRB were returned to the Kennedy Space Center and the external tank was towed burns up in the atmosphere.

Swell

  • NASA Countdown 101 (English)
  • NASA Countdown in detail (English)
  • Space Shuttle
Kennedy Space Center Launch Complex 39 Space Shuttle Orbital Maneuvering System Space Shuttle Main Engine
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