Launch Countdown
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Zarya Launch Countdown

MET GMT EST EVENT
T-8 hrs 2240 05:40 p.m. Power up Proton booster avionics & verify condition of main avionics systems
T-7 hrs 20 min 2320 06:20 p.m. -- Power up ‘Zarya’ command & control system heaters
T-7 hrs 2340 06:40 p.m. -- Power up ‘Zarya’ telemetry to verify onboard systems
-- Start data recorders
T-6 hrs 30 min 0010 07:10 p.m. -- Turn off telemetry system & powerdown electric buses
T-6 hrs 0040 07:40 p.m. -- Begin loading Proton oxidizer (2 hrs 40 min duration)
T-4 hrs 20 min 0220 09:20 p.m. -- Begin loading Proton propellant (1 hr 10 min duration)
T-2 hrs 40 min 0400 11:00 p.m. -- Thermal conditioning of Proton and ‘Zarya’
T-1 hr 10 min 0530 12:30 a.m. Retract service umbilical
Ventilate & purge gas cavities of Proton propellant tanks
Activate ground system electrical bus
Set start time for launch sequence mechanism and synchronize it with the universal time system
T-1 hr 5 min 0535 12:35 a.m. -- Adjust Proton booster trajectory
T-1 hr 0540 12:40 a.m. -- Power up ground station data handling complex
-- Power up ‘Zarya’ electrical buses and telemetry systems
T-45 min 0555 12:55 a.m. -- Zarya launch sequence initiated
T-40 min 0600 01:00 a.m. -- Radiotelemetry system activated
T-35 min 0605 01:05 a.m. -- Thermal control system activated
T-33 min 0607 01:07 a.m. -- Motion Control System activated in pre-launch mode
T-32 min 0608 01:08 a.m. -- Final alignment of gyroscopes for required liftoff azimuth
T-30 min 0610 01:10 a.m. -- Command and control system activated
T-25 min 0615 01:15 a.m. -- Fine tuning of gyro-stabilized launch platform of the Proton’s trajectory control system in the horizon plane and line of the azimuth
T-20 min 0620 01:20 a.m. -- Trajectory measurement system activated
T-18 min 0622 01:22 a.m. -- Zarya telemetry system (Syrius) activated
T-15 min 0625 01:25 a.m. -- Onboard telemetry monitoring system activated
-- Thermal monitoring of Proton booster engines
T-12 min 0628 01:28 a.m. -- Initiate rotation of gyro-stabilized platform of Proton trajectory control system
T-10 min 0630 01:30 a.m. -- Ground systems ready
T- 9 min 0631 01:31 a.m. -- Power switched from ground to Zarya onboard batteries
T- 8 min 0632 01:32 a.m. -- Steering jets of all booster stages confirmed in ‘zero position’
-- Ground command receives ‘control systems ready’ message
-- Ground command receives ‘auxiliary systems ready’ message
T-5 min 0635 01:35 a.m. -- Final launch operation program initiated
T-4 min 0636 01:36 a.m. -- Telemetry monitoring system switched to onboard power supply
T-3 min 30 sec 0636 01:36 a.m. -- Zarya telemetry system recording activated
T-3 min 0637 01:37 a.m. -- Power up of ground station recorders
T-2 min 0638 01:38 a.m. -- Ground command receives ‘main block ready’ command
T-1 min 0639 01:39 a.m. -- Ground station recorders activated
T-2.5 sec 0640 01:40 a.m. -- Time launch sequence mechanism issues ignition command for first stage engines
-- Proton control system switched to onboard power supply
T-1.6 sec 0640 01:40 a.m. -- Onboard system issues full-thrust command to engines
T Zero 0640:27 01:40:27 a.m. -- LAUNCH
+2 min 6 sec 0642 01:42 a.m. -- First stage separation (27.1 miles 43.6 km)
+3 min 3 sec 0642 01:42 a.m. -- Launch shroud jettison (125.8 miles 78.2 kilometers) (removal of Proton nose fairing)
-- Shroud panels deploy 2 folded command and control antennae and the telemetry system antenna on Zarya
+5 min 0645 01:45 a.m. -- Begin telemetry recording of Zarya module
+5 min 34 sec 0645 01:45 a.m. -- Second stage separation (222.5 miles 138.3 km)
+5 min 50 sec 0645 01:45 a.m. -- Prepare Zarya propulsion system for operations (30 sec)
+9 min 37 sec 0649 01:49 a.m. -- Third stage main engine shutdown command initiated
+9 min 47 sec 0650 01:50 a.m. -- Third stage separation command (297.6 miles 185 km)
-- Third stage steering jet is deactivated
-- Pyro locks securing Zarya to booster are released
-- Third stage solid body fuel jets fire to separate booster from Zarya
+9 min 49 sec 0650 01:50 a.m. -- Zarya command and control system activated -- External elements deployment program initiated
+10 min 5 sec 0650 01:50 a.m. -- Fire pyro pins to deploy ‘Kurs’ docking system antennae
+10 min 9 sec 0650 01:50 a.m. -- Deactivate telemetry system used during ascent
+10 min 11 sec 0650 01:50 a.m. -- Start spin-up of control system gyro motors
+10 min 37 sec 0650 01:50 a.m. -- Power up drives of ‘Kurs’ antennae deployment system
+12 min 20 sec 0652 01:52 a.m. -- Initiate trim of residual angular rates (27 sec)
+12 min 47 sec 0652 01:52 a.m. -- Power up docking system
+12 min 52 sec 0653 01:53 a.m. -- Initiate docking mechanism probe extension -- Deativate Zarya control system
+13 min 20 sec 0653 01:53 a.m. -- Solar array deployment (2 min)




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Updated: 11/19/1998

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