at the rate of 1°F per hour (see Figures 5-5 and 5-6). (For top hat and shroud temperatures. see Figures 5-7 and 5-8.) on. The P channel accumulator pulse, point 11, did not appear during the inadvertent turnWith the P channel on, as the battery voltages indicated, there are two possible reasons for not seeing the accumulator pulse: 1) 2) The sequencer power supply input voltage did not rise above -20 volts for the first part of the turn-on, delaying the start of the sequencer timing count such that it would not appear on Frame 3 point 11. The sequencer power supply input voltage dropped to less than 5 volts for 10 ms or longer, which reset the sequencer such that a full count was not completed during this turn-on. From the above data, it seems reasonable to conclude that the batteries experienced a load that was at least equivalent to TV warmup during all or part of the questionable period. Due to the recovery time of the batteries (which is dependent upon temperature and actual duration of load) it is conceivable that return of the batteries to their no load voltage level would not have been evident if the load was removed before the end of the 67 seconds. 2. Terminal Mode The terminal mode operation of the TV Subsystem started with the clock turning on the F channel at 33:09:05:42 GMT. The F channel voltage dropped 1. 25 volts (150 mv on telemetry point No. 5) indicating a load had been applied to the F battery. (See Table 5-5 and Figure 5-4.) The first RTC-7 command was sent at 33:09:08:00 GMT and the P battery voltage dropped 0.8 volt (100 mv on telemetry point No. 6) indicating a load on the P battery. During the subsequent frame of Channel 8, telemetry point 11 went from 0 to 4.5 volts indicating that the sequencer 5 minute timer was counting time. The F and P channels were expected to go into full power at 33:09: 11:00 and 33:09: 14:00 respectively. No RF carrier was received from either channel by the Goldstone tracking station. Two more RTC-7 commands were sent and verified at 33:09: 16: 10 and 33:09:21:00. This should have caused the P channel to send emergency telemetry for approximately 4 minutes and then transmit video along with the F channel for the remaining part of the flight. However, no video nor emergency telemetry was received during any part of the terminal mode. At approximately 23 seconds after the third B-20 event, indicating the third RTC-7 command had been received by the spacecraft, a small increase in the noise amplitude was noted on the data points but not on the zero reference or the baseline. This lasted for 1 minute and 42 seconds. There is no obvious explanation for this. 5-8 The lowest telemetry readings for both batteries occurred between 33:09:08 and 33:09: 18, after which time both battery telemetry points showed a very slight increase. 3. Flight Simulation Test The Ranger 9 TV Subsystem was tested at RCA in the thermal vacuum chamber under conditions simulating the RA-6 flight. The analog telemetry data was evaluated with the following results during the terminal mode: 1) There was little or no change in the battery or shroud temperatures. 2) 3) The F battery telemetry (point No. 5) dropped 100 mv (0.8 v actual)* at The P battery telemetry voltage dropped 150 mv (1.25 v actual) at the start On the basis of the appearance of the sequencer pulse and the drop in the battery voltages in the flight data it was concluded that there was only partial response of the TV Subsystem to the turn-on command at terminal. The apparent inversion with the loads shown for similar events during the terminal phase of the RA-6 flight are not significant, but are due to unequal charge and discharge characteristics of the respective batteries. |