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MECHANICAL DESIGN CONSIDERATIONS
To assure a higher level of mechanical integrity of the spacecraft hardware for future missions, a thorough recheck of load paths and structural integrity is underway. In particular, a thorough study is being undertaken on vibration transfer functions of specific payload packages and components that may be critical to certain types and amplitudes of vibration stimuli.
However, For example:
The exact flight environment of the TV Subsystem is not completely known. there are several areas where preventive improvements have been made.
Structural modifications have been made to the DCU to reduce vibration
Modifications to the TV transmitter power supply were made to improve the
Further investigations are being made on a shake table to determine vibration levels and frequencies at which critical components exhibit hazardous modes. Steps have been and will continue to be taken to alleviate or minimize the amplitudes of these modes. In particular, investigations of this type have been initiated on the following components:
In addition, efforts are underway (or have been completed) to reaffirm the integrity of all spot bonding, stiffeners, fasteners, potting, conformal coating, mountings, connectors, cable runs, venting, and insulation of exposed high voltage conductors.
PTM TV SUBSYSTEM FAILURE IN A VACUUM THERMAL TEST
On 27 June 1962, the PTM Ranger TV Subsystem, in the original RA-6 through RA-9 configuration, was operated during a vacuum-thermal test approximately 45 minutes after the
start of chamber pump down. The chamber pressure at the start of the test was 1.2 x 10-4 mm Hg. The sequence of events in Table P-1 occurred during this test.
Tests of individual assemblies following this failure revealed the following:
1) LCVR output to telemetry power supply was 27. 6 v (normal).
Command switch would not step.
All six camera assemblies and the transmitters were not operational
Subsequent investigation concluded that the failure of the PTM in this test was attributable to high voltage DC arcs caused by operation of the TV Subsystem when the pressure in the thermal shield or assemblies was in the critical pressure region. (See Appendix E.)
Power Control Unit
Power spectral density: see Section IV
Proof Test Model: see Section IV
Radio Corporation of America
Real Time Command (from ground station to S/C)
Stored Command (from CC&S to other units in S/C)
Silicon Controlled Rectifier: see Appendix M
Static Phase Error
Establishes warmup/full power interval and sync pulses for
The time of Agena separation
Separation of booster engines from Atlas
Type Approval (testing): see Section IV
Refers to area or maneuver when S/C nears its target
Cable with connector, from S/C to OSE, that separates at launch microsecond(s)