Detailed Chronology From 2.5 Minutes
Before The Accident To About 5 Minutes After
| GET * | |
| 55:52:31 | Master caution and warning triggered by low hydrogen pressure in tank No. 1. |
| 55:52:58 | CopCom (Charlie Duke): "13, we've got one more item for you, when you get a chance. We'd like you to stir up your cryo tanks. In addition, I have shaft and trunnion-" |
| 55:53:06 | Swigert- "Okay." |
| 55:53:07 | "-for looking at the Comet Bennett, if you need it." |
| 55:53:12 | Swigert- "Okay. Stand by." |
| 55:53:18 | Oxygen tank No. 1 fans on. |
| 55:53:19 | Oxygen tank No. 2 pressure decreases 8 psi. |
| 55:53:20 | Oxygen tank No. 2 fans turned on. |
| 55:53:20 | Stabilization control system electrical disturbance indicates a power transient. |
| 55:53:21 | Oxygen tank No. 2 pressure decreases 4 psi. |
| 55:53:22.718 | Stabilization control system electrical disturbance indicates a power transient. |
| 55:53:22.757 | 1.2-volt decrease in cic bus 2 voltage. |
| 55:53:22.772 | 11.1-amp rise in fuel cell 3 current for one sample. |
| 55:53:36 | Oxygen tank No. 2 pressure begins rise lasting for 24 seconds. |
| 55:53:38.057 | 11-volt decrease in ac bus 2 voltage for one sample. |
| 55:53:38.085 | Stabilization control system electrical disturbance indicates a power transient. |
| 55:53:41.172 | 22.9-amp rise in fuel cell 3 current for one sample. |
| 55:53:41.192 | Stabilization control system electrical disturbance indicates a power transient. |
| 55:54:00 | Oxygen tank No. 2 pressure rise ends of a pressure of 953.8 psia. |
| 55:54:15 | Oxygen tank No. 2 pressure begins to rise. |
| 55:54:30 | Oxygen tank No. 2 quantity drops from full scale for 2 seconds and then reads 75.3 percent. |
| 55:54:31 | Oxygen tank No. 2 temperature begins to rise rapidly. |
| 55:54:43 | Flow rate of oxygen to all three fuel cells begins to decrease. |
| 55:54:45 | Oxygen tank No. 2 pressure reaches maximum volue of 1008.3 psia. |
| 55:54:51 | Oxygen tank No. 2 quantity jumps to off-scale high and then begins to drop until the time of telemetry loss, indicating from 2.5 minutes be re failed sensor. |
| 55:54:52 | Oxygen tank No. 2 temperature reads -151.30° F. |
| 55:54:52.703 | Oxygen tank No. 2 temperature suddenly goes off-scale low, indicating failed sensor. |
| 55:54:52.763 | Last telemetered pressure from oxygen tank No. 2 before telemetry loss is 995.7 psia. |
| 55:54:53.182 | Sudden accelerometer activity on X, Y, Z axes. |
| 55:54:53.220 | Stabilization control system rate changes begin. |
| 55:54:53.323 | Oxygen tank No. 1 pressure drops 4.2 psi. |
| 55:54:53.500 | 2.8-amp rise in total fuel cell current. |
| 55:54:53.542 | X, Y, and Z accelerations in CM indicate 1.179, 0.65g, and 0.659. |
| 55:54:53.555 | Loss of telemetry. |
| 55:54:53.555+ | Master caution and warning triggered by dc main bus 8 undervoltage. Alarm is turned off in 6 seconds. All indications are that the cryogenic oxygen tank No. 2 lost pressure in this time period and the panel separated. |
| 55:54:54.741 | Nitrogen pressure in fuel cell 1 is off-scale low indicating failed sensor. |
| 55:54:55.350 | Telemetry recovered. |
| 55:54:56 | Service propulsion system engine valve body temperature begins a rise of 1.65° F in 7 seconds. Dc main bus A decreases 0.9 volt to 28.5 volts und dc main bus B decreases 0.9 volt to 29.0 volts. Total fuel cell current is 15 amps higher than the final value before telemetry loss. High current continues for 19 seconds. Oxygen tank No. 2 temperature reads offscale high after telemetry recovery, probably indicating failed sensors. Oxygen tank No. 2 pressure reads offscale low following telemetry recovery, indicating a broken supply line, a tank pressure below 19 psi, or a failed sensor. Oxygen tank No. 1 pressure reads 781.9 psia und begins to drop. |
| 55:54:57 | Oxygen tank No. 2 quantity reads off-scale high following telemetry recovery incdicating failed sensor. |
| 55:55:01 | Oxygen flow rates to fuel cells 1 und 3 approached zero after decreasing for 7 seconds. |
| 55:55:02 | The surface temperature of the service module oxidizer tank in bay 3 begins a 3.8° F increase in a 15-second period. The service propulsion system helium tank temperature begins a 3.8° F increase in a 32-second period. |
| 55:55:09 | Dc main bus A voltage recovers to minutes after 29.0 volts; dc main bus 8 recovers to 28.8. |
| 55:55:20 | Swigert: "Okay, Houston, we'ye had a problem here." |
| 55:55:28 | Duke: "This is Houston. Say again, please." |
| 55:55:35 | Lovell: "Houston, we've had a problem. We've had a main B bus undervolt. |
| 55:55:42 | Duke: "Roger. Main B undervolt." |
| 55:55:49 | Oxygen tank No. 2 temperature begins steady drop lasting 59 seconds, indicating failed sensor. |
| 55:56:10 | Haise: "Okay. Right now, Houston, the voltage is - is looking good. And we had a pretty large bang associated with the caution und warning there. And as I recall, main B was the one that had an amp spike on it once before." |
| 55:56:30 | Duke: "Roger, Fred." |
| 55:56:38 | Oxygen tank No. 2 quantity becomes erratic for 69 seconds before assuming an off-scale-low state, indicating failed sensor. |
| 55:56:54 | Haise: "In the interim here, we're starting to go ahead und button up the tunnel again." |
| 55:57:04 | Haise: "That jolt must have rocked the sensor on - see now - oxygen quantity 2. It was oscillating down around 20 to 60 percent. Now it's full-scale high." |
| 55:57:39 | Master caution und warning triggered by dc main bus B undervoltage alarm is turned off in 6 seconds. |
| 55:57:40 | Dc main bus B drops below 2 25 volts und continues to fall rapidly. |
| 55:57:44 | Lovell: "Okay. And we're looking at our service module RCS helium 1. We have - B is barber poled und D is barber poled, helium 2, D is barber pole, und secondary propellants, I have A und C barber pole." Ac bus fails within 2 seconds. |
| 55:57:45 | Fuel cell 3 fails. |
| 55:57:59 | Fuel cell current begins to decrease. |
| 55:58:02 | Master caution und warning caused by ac bus 2 being reset. |
| 55:58:06 | Master caution und warning triggered by dc main bus A undervoltage. |
| 55:58:07 | Dc main bus A drops below 26 25 volts und in the next few seconds levels oft at 25.5 volts. |
| 55:58:07 | Haise: "Ac 2 is showing zip." |
| 55:58:25 | Haise: "Yes, we got a main bus A undervolt now, too, showing. Its reading about 251/2. Main B is reading zip right now." |
| 56:00:06 | Master caution und warning triggered by high hydrogen flow rate to fuel cell 2. |
* GET: Ground Elapsed Time
(hours, minutes, seconds)
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