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science, and the desire to have every flight work, and, I think, overall our flight record has been excellent. I think JPL's record has been outstanding. I think when you look at the troubles we have had with Ranger and compare the successes where one Mariner flight might be worth a very large number of some other type of flight, you can only say that these men have used every bit of care that they possibly could, and that they have realized that if in testing, for instance, they should destroy a spacecraft, you may well destroy a vehicle that would have worked, so we have a very hard decision at all points here.
My view is that the schedules have been pretty hardboiled, they have not been unrealistic, and we have slipped them when it was necessary to gain some real advantage by doing so and JPL knows that. We have never insisted that a schedule be met if in their judgment or ours it was unwise. We have both agreed on the flights.
Mr. KARTH. Are there any further questions?
I want to thank you very much, Mr. Webb and Dr. Seamans. We may submit some questions to you in writing that may have escaped the committee members at this meeting, and if we do we would sincerely request that you respond to them.
Mr. WEBB. We would be happy to come back, or answer your questions at any time, Mr. Chairman.
Mr. KARTH. Thank you very much. The subcommittee is adjourned.
(Whereupon, at 12.23 p.m., the subcommittee adjourned.)
ENGINEERING PLANNING DOCUMENT
RANGER VI FAILURE ANALYSIS AND SUPPORTING INVESTIGATIONS
27 MARCH 1964
RANGER PROJECT MANAGER
JET PROPULSION LABORATORY
Jet Propulsion Laboratory
This is the final report by the Jet Propulsion Laboratory of the RA-6 investigation that was initiated on 2 February 1964 to investigate the reason for the failure in the Ranger 6 mission, and to establish measures to reduce the possibility of such failures in future flights.
The mission of the Ranger 6 flight was to obtain high resolution television pictures of the lunar surface. The RA-6 Spacecraft was launched from Cape Kennedy, AMR, on an Atlas D/Agena-B vehicle on 30 January 1964. Impact with the lunar surface occurred at 09:24:33 GMT on 2 February 1964. The primary objective of the mission was not attained, since no television pictures were received.
The investigation was unable to determine a single simple failure that would account for all of the events. However, the most plausible failure mechanism was the destruction of the transmitter high voltage supplies during an inadvertent turn-on while the spacecraft was in a critical pressure environment. This conclusion was prompted by the unscheduled appearance of telemetry signals on Channel 8 for 67 seconds following booster engine cutoff.
All possible conditions that could have contributed to the cause of failure were investigated and diagnosed. Recommendations related to the area of investigation were made to remedy these potential fault conditions on future flights. The primary recommendation involves a modification of the TV subsystem control circuitry to prevent unscheduled turn-on during the critical phase of flight.
Pertinent Flight Data and Supporting Information
1. Inadvertent Turn-On
TV Subsystem Command/Control Circuit
TV Subsystem Operation in Critical Pressure Environment
C. Preventive Measures
BOOST PHASE ENVIRONMENT AND PREFLIGHT TESTING
B. Boost Phase Vibration
CHANNEL 8 TELEMETRY
B. Pertinent Data and Observations
Analysis and Conclusions
Terminal Mode . .
Flight Simulation Test
1. High Current Voltage Regulator (HCR).
3. Command Control Unit (CCU)
5. Command Functions ....
Command Circuits Ground Lockout
Alternate Switching Technique
1. The 90 Point Telemetry Changes
2. The 15 Point Telemetry Changes
Other Preventive Measures
ANALYSIS OF CHANNEL 8 OPERATION DURING BOOST
Powering the Low Current Regulator (LCR) by Stepping the Command
Cruise Mode Telemetry Turn-On During Launch Phase