Reports/Apollo 17/Saturn V flight evaluation/2 Event Times
[edit] 2.1 Summary of events
Range zero occurred at 00:33:00 Eastern Standard Time (EST) (05:33:00 Universal Time [UT]) December 7, 1972. Range time is the elapsed time from range zero, and is the time used throughout this report unless otherwise noted. Time from base time is the elapsed time from the start of the indicated time base. Table 2-1 presents the time bases used in the flight sequence program.
Table 2-1. Time Base Summary
| Time Base | Vehicle Time* Seconds (hr:min:sec) | Ground Time** Seconds (hr:min:sec) | Signal Start |
|---|---|---|---|
| T0 | -16.96 | -16.96 | Guidance Reference Release |
| T1 | 0.63 | 0.63 | IU Umbilical Disconnect Sensed by LVDC |
| T2 | 139.44 | 139.44 | Initiated by LVDC 0.013 Seconds after T1 +138.8 Seconds |
| T3 | 161.22 | 161.22 | S-IC OECO Sensed by LVDC |
| T4 | 559.65 | 559.65 | S-II OECO Sensed by LVDC |
| T5 | 702.87 | 702.87 | S-IVB ECO (Velocity) Sensed by LVDC |
| T6 | 10,978.65 (03:02:58.65) | 10,978.65 (03:02:58.65) | Restart Equation Solution |
| T7 | 11,907.87 (03:18:27.87) | 11,907.87 (03:18:27.87) | S-IVB ECO (Velocity) Sensed by LVDC |
| T8 | 18,179.88 (05:02:59.88) | 18,180.00 (05:03:00.00) | Initiated by Ground Command |
| * Range Time of occurrence as indicated by uncorrected LVDC clock, i.e., the time of event as tagged onboard, converted to range time. | |||
| ** Range Time of Ground receipt of telemetered signal from vehicle. Includes telemetry transmission time and LVDC clock correction. Figure 2-1. | |||
The start of Time Bases T0, T1, and T2 were nominal. T3, T4 and T5 were initiated approximately 0.5 seconds early, 0.4 seconds early, and 4.1 seconds early, respectively, due to variations in the stage burn times. These variations are discussed in Sections 5, 6 and 7 of this document. Start times of T6 and T7 were 1.9 seconds early and 2.1 seconds late, respectively. T8 was initiated by the receipt of a ground command.
Figure 2-1 shows the mean difference between ground station receipt time and vehicle tagged time which may be used for precise comparisons between onboard guidance and navigation data that is time-tagged onboard and other data that is time-tagged by time of telemetry signal receipt at a ground station.
A sumpary of significant event times for AS-512 is given in Table 2-2. The preflight predicted times were adjusted to match the actual first motion time. The predicted times for establishing actual minus predicted times in Table 2-2 were taken from 40M33627D, "Interface Control Document Definition of Saturn SA-511, 512 and 514 Flight Sequence Program" and from the AS-512 Postlaunch Operational Trajectory (OT). The postlaunch operational trajectory, MSFC Memorandum S&E-AERO-MFT-200-72, correcting the earlier OT for the adjusted flight azimuth, was used because of the launch delay.
[edit] 2.2 Variable time and command switch selector events
Table 2-3 lists the switch selector events which were issued during the flight, but were not programmed for specific times.