| DATE TIME (EST) |
MET |
EVENT |
| 02/11/00 4:10:00 AM |
T - 000/06:00:00 |
Verification of the launch commit criteria is complete at this time. The liquid oxygen and liquid hydrogen systems chill-down commences in order to condition the ground line and valves as well as the external tank (ET) for cryo loading. Orbiter fuel cell power plant activation is performed. |
| 02/11/00 4:20:00 AM |
T - 000/05:50:00 |
The space shuttle main engine (SSME) liquid hydrogen chill-down sequence is initiated by the launch processing system (LPS). The liquid hydrogen recirculation valves are opened and start the liquid hydrogen recirculation pumps. As part of the chill-down sequence, the liquid hydrogen prevalves are closed and remain closed until T minus 9.5 seconds. |
| 02/11/00 4:40:00 AM |
T - 000/05:30:00 |
Liquid oxygen chill-down is complete. The liquid oxygen loading begins. The liquid oxygen loading starts with a "slow fill" in order to acclimate the ET. Slow fill continues until the tank is 2-percent full. |
| 02/11/00 4:55:00 AM |
T - 000/05:15:00 |
The liquid oxygen and liquid hydrogen slow fill is complete and the fast fill begins. The liquid oxygen and liquid hydrogen fast fill will continue until that tank is 98-percent full. |
| 02/11/00 5:10:00 AM |
T - 000/05:00:00 |
The calibration of the inertial measurement units (IMUs) starts. The three IMUs are used by the orbiter navigation systems to determine the position of the orbiter in flight. |
| 02/11/00 5:40:00 AM |
T - 000/04:30:00 |
The orbiter fuel cell power plant activation is complete. |
| 02/11/00 6:10:00 AM |
T - 000/04:00:00 |
The Merritt Island (MILA) antenna, which transmits and receives communications, telemetry and ranging information, alignment verification begins. |
| 02/11/00 6:25:00 AM |
T - 000/03:45:00 |
The liquid hydrogen fast fill to 98 percent is complete, and a slow topping-off process is begun and stabilized to 100 percent. |
| 02/11/00 6:40:00 AM |
T - 000/03:30:00 |
The liquid oxygen fast fill is complete to 98 percent. |
| 02/11/00 6:50:00 AM |
T - 000/03:20:00 |
The main propulsion system (MPS) helium tanks begin filling from 2,000 psi to their full pressure of 4,500 psi. |
| 02/11/00 6:55:00 AM |
T - 000/03:15:00 |
Liquid hydrogen stable replenishment begins and continues until just minutes prior to T minus zero. |
| 02/11/00 7:00:00 AM |
T - 000/03:10:00 |
Liquid oxygen stable replenishment begins and continues until just minutes prior to T minus zero. |
| 02/11/00 7:10:00 AM |
T - 000/03:00:00 |
Begin 2-hour planned hold. An inspection team examines the ET for ice or frost formation on the launch pad during this hold. The MILA antenna alignment is completed. The orbiter closeout crew goes to the launch pad and prepares the orbiter crew compartment for flight crew ingress. |
| 02/11/00 9:10:00 AM |
T - 000/03:00:00 |
Two-hour planned hold ends. |
| 02/11/00 9:15:00 AM |
T - 000/02:55:00 |
Flight crew departs Operations and Checkout (O&C) Building for launch pad. |
| 02/11/00 9:45:00 AM |
T - 000/02:25:00 |
Flight crew orbiter and seat ingress occurs. |
| 02/11/00 10:00:00 AM |
T - 000/02:10:00 |
Post ingress software reconfiguration occurs. |
| 02/11/00 10:10:00 AM |
T - 000/02:00:00 |
Checking of the launch commit criteria starts at this time. |
| 02/11/00 10:10:00 AM |
T - 000/02:00:00 |
The ground launch sequencer (GLS) software is initialized. |
| 02/11/00 10:20:00 AM |
T - 000/01:50:00 |
The solid rocket boosters' (SRBs') hydraulic pumping units' gas generator heaters are turned on and the SRBs' aft skirt gaseous nitrogen purge starts. |
| 02/11/00 10:20:00 AM |
T - 000/01:50:00 |
The SRB rate gyro assemblies (RGAs) are turned on. The RGAs are used by the orbiter's navigation system to determine rates of motion of the SRBs during first-stage flight. |
| 02/11/00 10:35:00 AM |
T - 000/01:35:00 |
The flight crew starts the communications checks. The orbiter reaction control system (RCS) control drivers are powered up. The orbiter reaction control system (RCS) control drivers are powered up. |
| 02/11/00 10:45:00 AM |
T - 000/01:25:00 |
The SRB RGA torque test begins. |
| 02/11/00 10:50:00 AM |
T - 000/01:20:00 |
Orbiter side hatch is closed. |
| 02/11/00 11:00:00 AM |
T - 000/01:10:00 |
Orbiter side hatch seal and cabin leak checks are performed. |
| 02/11/00 11:09:00 AM |
T - 000/01:01:00 |
IMU preflight align begins. Flight crew functions from this point on will be initiated by a call from the orbiter test conductor (OTC) to proceed. The flight crew will report back to the OTC after completion. |
| 02/11/00 11:10:00 AM |
T - 000/01:00:00 |
The orbiter RGAs and AAs are tested. |
| 02/11/00 11:20:00 AM |
T - 000/00:50:00 |
The orbiter RGAs and AAs are tested. |
| 02/11/00 11:25:00 AM |
T - 000/00:45:00 |
Cabin vent redundancy check is performed. The GLS mainline activation is performed. |
| 02/11/00 11:30:00 AM |
T - 000/00:40:00 |
The eastern test range (ETR) shuttle range safety system (SRSS) terminal count closed-loop test is accomplished. Cabin leak check is completed. |
| 02/11/00 11:38:00 AM |
T - 000/00:32:00 |
The backup flight control system (BFS) computer is configured. |
| 02/11/00 11:40:00 AM |
T - 000/00:30:00 |
The gaseous nitrogen system for the orbital maneuvering system (OMS) engines is pressurized for launch. Crew compartment vent valves are opened. |
| 02/11/00 11:44:00 AM |
T - 000/00:26:00 |
The ground pyro initiator controllers (PICs) are powered up. They are used to fire the SRB hold-down posts, liquid oxygen and liquid hydrogen tail service mast (TSM), and ET vent arm system pyros at lift-off and the SSME hydrogen gas burn system prior to SSME ignition. |
| 02/11/00 11:45:00 AM |
T - 000/00:25:00 |
Simultaneous air-to-ground voice communications are checked. Weather aircraft are launched. |
| 02/11/00 11:48:00 AM |
T - 000/00:22:00 |
The primary avionics software system (PASS) is transferred to the BFS computer in order for both systems to have the same data. In case of a PASS computer system failure, the BFS computer will take over control of the shuttle vehicle during flight. |
| 02/11/00 11:49:00 AM |
T - 000/00:21:00 |
The crew compartment cabin vent valves are closed. |
| 02/11/00 11:50:00 AM |
T - 000/00:20:00 |
A 10-minute planned hold starts. All computer programs in the firing room are verified to ensure that the proper programs are available for the final countdown. The test team is briefed on the recycle options in case of an unplanned hold. The landing convoy status is again verified and the landing sites are verified ready for launch. The IMU preflight alignment is verified coming out of the hold. This configures the computer memory to a terminal countdown configuration.complete. Preparations are made to transition the orbiter onboard computers to Major Mode (MM) 101 upon |
| 02/11/00 12:00:00 PM |
T - 000/00:20:00 |
The 10-minute hold ends. Transition to MM-101. The PASS onboard computers are dumped and compared to verify the proper onboard computer configuration for launch. |
| 02/11/00 12:01:00 PM |
T - 000/00:19:00 |
The flight crew configures the backup computer to MM-101 and the test team verifies the BFS computer is tracking the PASS computer systems. The flight crew members configure their instruments for launch. |
| 02/11/00 12:02:00 PM |
T - 000/00:18:00 |
The Mission Control Center-Houston (MCC-H) now loads the onboard computers with the proper guidance parameters based on the prestated lift-off time. |
| 02/11/00 12:04:00 PM |
T - 000/00:16:00 |
The MPS helium system is reconfigured by the flight crew for launch. |
| 02/11/00 12:05:00 PM |
T - 000/00:15:00 |
The OMS/RCS crossfeed valves are configured for launch. All test support team members verify they are "go for launch." |
| 02/11/00 12:08:00 PM |
T - 000/00:12:00 |
Emergency aircraft and personnel are verified on station. |
| 02/11/00 12:10:00 PM |
T - 000/00:10:00 |
All orbiter aerosurfaces and actuators are verified to be in the proper configuration for hydraulic pressure application. The NASA test director gets a "go for launch" verification from the launch team. |
| 02/11/00 12:11:00 PM |
T - 000/00:09:00 |
A planned 10-minute hold starts. NASA and contractor project managers will be formally polled by the deputy support team members verify that they are "go for launch." Final GLS configuration is complete. |
| 02/11/00 12:11:00 PM |
T - 000/00:09:00 |
The GLS auto sequence starts and the terminal countdown begins. Counting From this point, the GLSs in the integration and backup consoles are the primary control until T-0 in conjunction with the onboard orbiter PASS redundant-set computers. |
| 02/11/00 12:21:00 PM |
T - 000/00:09:00 |
Operations recorders are on. MCC-H, Johnson Space Center, sends a command to turn these recorders on. They record shuttle system performance during ascent and are dumped to the ground once orbit is achieved. |
| 02/11/00 12:22:00 PM |
T - 000/00:08:00 |
Payload and stored prelaunch commands proceed. |
| 02/11/00 12:22:30 PM |
T - 000/00:07:30 |
The orbiter access arm (OAA) connecting the access tower and the orbiter side hatch is retracted. If an emergency arises requiring flight crew activation, the arm can be extended either manually or by GLS computer control in approximately 30 seconds or less. |
| 02/11/00 12:24:00 PM |
T - 000/00:06:00 |
APU prestart occurs. |
| 02/11/00 12:25:00 PM |
T - 000/00:05:00 |
Orbiter APUs start. The orbiter APUs provide pressure to the three orbiter hydraulic systems. These systems are used to move the SSME engine nozzles and aerosurfaces. |
| 02/11/00 12:25:00 PM |
T - 000/00:05:00 |
ET/SRB range safety system (RSS) is armed. At this point, the firing circuit for SRB ignition and destruct devices is mechanically enabled by a motor-driven switch called a safe and arm device (S&A). |
| 02/11/00 12:25:30 PM |
T - 000/00:04:30 |
As a preparation for engine start, the SSME main fuel valve heaters are turned off. |
| 02/11/00 12:26:00 PM |
T - 000/00:04:00 |
The final helium purge sequence, purge sequence 4, on the SSMEs is started in preparation for engine start. |
| 02/11/00 12:26:05 PM |
T - 000/00:03:55 |
At this point, all of the elevons, body flap, speed brake, and rudder are moved through a preprogrammed pattern. This is to ensure that they will be ready for use in flight. |
| 02/11/00 12:26:30 PM |
T - 000/00:03:30 |
Transfer to internal power is done. Up to this point, power to the space vehicle has been shared between ground power supplies and the onboard fuel cells. The ground power is disconnected and the vehicle goes on internal power at this time. It will remain on internal power through the rest of the mission. |
| 02/11/00 12:26:35 PM |
T - 000/00:03:25 |
The SSMEs' nozzles are moved (gimbaled) through a preprogrammed pattern to ensure that they will be ready for ascent flight control. At completion of the gimbal profile, the SSMEs' nozzles are in the start position. |
| 02/11/00 12:27:05 PM |
T - 000/00:02:55 |
ET liquid oxygen prepressurization is started. At this point, the liquid oxygen tank vent valve is closed and the ET liquid oxygen tank is pressurized to its flight pressure of 21 psi. |
| 02/11/00 12:27:10 PM |
T - 000/00:02:50 |
The gaseous oxygen arm is retracted. The cap that fits over the ET nose cone to prevent ice buildup on the oxygen vents is raised off the nose cone and retracted. |
| 02/11/00 12:27:25 PM |
T - 000/00:02:35 |
Up until this time, the fuel cell oxygen and hydrogen supplies have been adding to the onboard tanks so that a full load at lift-off is assured. This filling operation is terminated at this time. |
| 02/11/00 12:27:30 PM |
T - 000/00:02:30 |
The caution/warning memory is cleared. |
| 02/11/00 12:28:03 PM |
T - 000/00:01:57 |
Since the ET liquid hydrogen tank was filled, some of the liquid hydrogen has turned into gas. In order to keep pressure in the ET liquid hydrogen tank low, this gas was vented off and piped out to a flare stack and burned. In order to maintain flight level, liquid hydrogen was continuously added to the tank to replace the vented hydrogen. This operation terminates, the liquid hydrogen tank vent valve is closed, and the tank is brought up to a flight pressure of 44 psia at this time. |
| 02/11/00 12:28:45 PM |
T - 000/00:01:15 |
The sound suppression system will dump water onto the mobile launcher platform (MLP) at ignition in order to dampen vibration and noise in the space shuttle. The firing system for this dump, the sound suppression water power bus, is armed at this time. |
| 02/11/00 12:29:00 PM |
T - 000/00:01:00 |
The SRB joint heaters are deactivated. |
| 02/11/00 12:29:05 PM |
T - 000/00:00:55 |
The SRB MDM critical commands are verified. |
| 02/11/00 12:29:13 PM |
T - 000/00:00:47 |
The liquid oxygen and liquid hydrogen outboard fill and drain valves are closed. |
| 02/11/00 12:29:20 PM |
T - 000/00:00:40 |
The external tank bipod heaters are turned off. |
| 02/11/00 12:29:22 PM |
T - 000/00:00:38 |
The onboard computers position the orbiter vent doors to allow payload bay venting upon lift-off and ascent in the payload bay at SSME ignition. The SRB forward MDM is locked out. |
| 02/11/00 12:29:23 PM |
T - 000/00:00:37 |
The gaseous oxygen ET arm retract is confirmed. |
| 02/11/00 12:29:29 PM |
T - 000/00:00:31 |
The GLS sends "go for redundant set launch sequence start." At this point, the four PASS computers take over main control of the terminal count. Only one further command is needed from the ground, "go for main engine start," at approximately T minus 9.7 seconds. The GLS in the integration console in the launch control center still continues to monitor several hundred launch commit criteria and can issue a cutoff if a discrepancy is observed. The GLS also sequences ground equipment and sends selected vehicle commands in the last 31 seconds. |
| 02/11/00 12:29:32 PM |
T - 000/00:00:28 |
Two hydraulic power units in each SRB are started by the GLS. These provide hydraulic power for SRB nozzle gimbaling for ascent first-stage flight control. The orbiter vent door sequence starts. |
| 02/11/00 12:29:39 PM |
T - 000/00:00:21 |
The SRB gimbal profile is complete. As soon as SRB hydraulic power is applied, the SRB engine nozzles are commanded through a preprogrammed pattern to assure that they will be ready for ascent flight control during first stage. |
| 02/11/00 12:29:39 PM |
T - 000/00:00:21 |
The liquid hydrogen high-point bleed valve is closed. The SRB gimbal test begins. |
| 02/11/00 12:29:42 PM |
T - 000/00:00:18 |
The onboard computers arm the explosive devices, the pyrotechnic initiator controllers, that will separate the T-0 umbilicals, the SRB hold-down posts, and SRB ignition, which is the final electrical connection between the ground and the shuttle vehicle. |
| 02/11/00 12:29:44 PM |
T - 000/00:00:16 |
The sound suppression system water is activated. |
| 02/11/00 12:29:45 PM |
T - 000/00:00:15 |
If the SRB pyro initiator controller (PIC) voltage in the redundant-set launch sequencer (RSLS) is not within limits in 3 seconds, SSME start commands are not issued and the onboard computers proceed to a countdown hold. |
| 02/11/00 12:29:47 PM |
T - 000/00:00:13 |
The aft SRB MDM units are locked out. This is to protect against electrical interference during flight. The electronic lock requires an unlock command before it will accept any other command. SRB SRSS inhibits are removed. The SRB destruct system is now live. |
| 02/11/00 12:29:48 PM |
T - 000/00:00:12 |
The MPS helium fill is terminated. The MPS helium system flows to the pneumatic control system at each SSME inlet to control various essential functions. |
| 02/11/00 12:29:50 PM |
T - 000/00:00:10 |
LPS issues a "go" for SSME start. This is the last required ground command. The ground computers inform the orbiter onboard computers that they have a "go" for SSME start. The GLS retains hold capability until just prior to SRB ignition. |
| 02/11/00 12:29:51 PM |
T - 000/00:00:09.7 |
In preparation for SSME ignition, flares are ignited under the SSMEs. This burns away any free gaseous hydrogen that may have collected under the SSMEs during prestart operations. The orbiter goes on internal cooling at this time; the ground coolant units remain powered on until lift-off as a contingency for an aborted launch. The orbiter will redistribute heat within the orbiter until approximately 125 seconds after lift-off, when the orbiter flash evaporators will be turned on. |
| 02/11/00 12:29:51 PM |
T - 000/00:00:09.7 |
Liquid hydrogen recirculation pumps are turned off. The recirculation pumps provide for flow of fuel through the SSMEs during the terminal count. These are supplied by ground power and are powered in preparation for SSME start. |
| 02/11/00 12:29:51 PM |
T - 000/00:00:09.5 |
The SSME engine chill-down sequence is complete and the onboard computers command the three MPS liquid hydrogen prevalves to open. (The MPS's three liquid oxygen prevalves were opened during ET tank loading to permit engine chill-down.) These valves allow liquid hydrogen and oxygen flow to the SSME turbopumps. |
| 02/11/00 12:29:51 PM |
T - 000/00:00:09.5 |
Command decoders are powered off. The command decoders are units that allow ground control of some onboard components. These units are not needed during flight. |
| 02/11/00 12:29:54 PM |
T - 000/00:00:06.6 |
The main fuel and oxidizer valves in each engine are commanded open by the onboard computers, permitting fuel and oxidizer flow into each SSME |
| 02/11/00 12:29:56 PM |
T - 000/00:00:04.6 |
All three SSMEs are verified to be at 100-percent thrust and the SSMEs are gimbaled to the lift-off position. If one or more of the three SSMEs does not reach 100-percent thrust at this time, all SSMEs are shut down, the SRBs are not ignited, and an RSLS pad abort occurs. The GLS RSLS will perform shuttle and ground systems safing. Vehicle bending loads caused by SSME thrust buildup are allowed to initialize before SRB ignition. The vehicle moves towards ET including ET approximately 25.5 inches. |
| 02/11/00 12:30:00 PM |
T - 000/00:00:00 |
The two SRBs are ignited under command of the four onboard PASS computers, the four hold-down explosive bolts on each SRB are initiated (each bolt is 28 inches long and 3.5 inches in diameter), and the two T-0 umbilicals on each side of the spacecraft are retracted. The onboard timers are started and the ground launch sequence is terminated. All three SSMEs are at 104-percent thrust. Boost guidance in attitude hold. |
| 02/11/00 12:30:00 PM |
T - 000/00:00 |
Lift-off. |
