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Statistical information for the Apollo command module water landings is presented. This information includes the probability of occurrence of various impact conditions, a successful impact, and body X-axis loads of various magnitudes.
The flammability test program for Apollo command module and lunar module mockups is described. The fire safety design of the modules was verified by performing deliberate ignitions at many locations while the interior atmosphere was controlled to simulate realistic flight conditions. The data obtained for each test and restrictions on various materials are discussed.
Analyses were performed to determine the structural loads caused by maneuvers of the docked Apollo command and service module/lunar module (CSM/LM). Results of CSM/LM docked interface loads analyses and service-propulsion-system engine support structure load analyses are compared with the structural allowable loads of the CSM/LM docked interface and the service-propulsion-system engine thrust mount, respectively, for different phases of spaceflight operations. An analysis also was performed to investigate the loads that resulted from the failure case in which the LM descent propulsion system is started in the full-throttle position.
The development of the guidance targeting techniques for the Apollo command module and launch vehicle is discussed for four types of maneuvers: (1) translunar injection, (2) translunar midcourse, (3) lunar orbit insertion, and (4) return to earth. The development of real-time targeting programs for these maneuvers and the targeting procedures represented are discussed. The material is intended to convey historically the development of the targeting techniques required to meet the defined target objectives and to illustrate the solutions to problems encountered during that development.
Calibration curves for the Apollo 16 command service module pulse code modulation downlink and onboard display are presented. Subjects discussed are: (1) measurement calibration curve format, (2) measurement identification, (3) multi-mode calibration data summary, (4) pulse code modulation bilevel events listing, and (5) calibration curves for instrumentation downlink and meter link.
Detailed review of component failure histories, qualification adequacy, manufacturing flow, checkout requirements and flow, ground support equipment interfaces, subsystem interface verification, protective devices, and component design did not reveal major weaknesses in the command service module (CSM) reaction control system (RCS). No changes to the CSM RCS were recommended. The assessment reaffirmed the adequacy of the CSM RCS for future Apollo missions.
Full-scale-model and actual spacecraft were impact tested to define the emergency land-landing capability of the Apollo command module. Structural accelerations and strains were recorded on analog instrumentation, and a summary to these data is included. The landing kinematics were obtained from high-speed photography. Photographs of the structural damage caused during the tests are included. Even though extensive damage can be expected, the crew will receive nothing more than minor injuries during the majority of the probable landing conditions.
The MULTIPAC is a central data system developed for deep-space probes with the distinctive feature that it may be repaired during flight via command and telemetry links by reprogramming around the failed unit. The computer organization uses pools of identical modules which the program organizes into one or more computers called processors. The interaction of these modules is dynamically controlled by the program rather than hardware. In the event of a failure, new programs are entered which reorganize the central data system with a somewhat reduced total processing capability aboard the spacecraft. Emphasis is placed on the evolution of the system architecture and the final overall system design rather than the specific logic design.
System, fabricated of highly-reliable digital logic elements, operates on binary pulse-code-modulated signals and derives internal synchronization from data signal. All-digital implementation of detector develops synchronization from data signal by computer cross-correlation of command modulation signal with its expected forms in sequence and adjusts detector phases in accordance with correlation peaks.
Generator measures period between zero crossings of reference signal and accepts as correct timing points only those zero crossings which occur acceptably close to nominal time predicted from last accepted command. Unidirectional crossover points are used exclusively so errors from analog nonsymmetry of crossover detector are avoided.
Pressure signatures were measured at roll angles ranging from 0 to 180 deg for a .016-scale model of the Apollo Command Module spacecraft at 25 deg angle of attack. The test Mach numbers ranged from 1.50 to 10.02.
The command module television camera monitor exhibited loss of horizontal synchronization during the initial usage. This condition cleared and performance of the monitor was normal until the press conference telecast during the transearth coast phase. At that time, the monitor had the same horizontal synchronization problem reported during the initial usage. The horizontal hold control adjustment would not correct the condition. The monitor was turned off for approximately 5 minutes, then turned back on, after which the monitor's picture was normal. The loss of horizontal synchronization was most likely caused by either an intermittent condition in the precision voltage regulator circuit assembly in the low voltage power supply, or the shift of the stable range of the horizontal potentiometer setting when warming up after turn-on.
A water-landing requirement and two stable flotation attitudes required that a system be developed to ensure that the Apollo command module would always assume an upright flotation attitude. The resolution to the flotation problem and the uprighting concepts, design selection, design changes, development program, qualification, and mission performance are discussed for the uprighting system, which is composed of inflatable bags, compressors, valves, and associated tubing.
An investigation was made into the temporary loss of command module color television picture by the ground station converter at Mission Control Center. Results show the picture loss was caused by a false synchronization pulse that resulted from the inability of the black level clipping circuit to respond adequately to the video signal when bright sunlight suddenly entered the camera's field of view.
The reaction control systems of the Apollo command and service module were developed and modified between July 1961 and July 1969. The successful development of these systems, as part of the Apollo Program, was the result of extensive testing, retesting, and modifications of the hardware to ensure system capability and intrasystem compatibility.
A review of the Apollo command and service module instrumentation subsystem is presented. The measurements provided, design aspects considered, problems encountered, and flight results obtained are discussed.
The Apollo command module crew-couch/restraint and load-attenuation system was required to support and restrain the crewman during mission phases and to limit the load imposed on the crewman during landing. Component designs evolved when requirements changed and tests were conducted. Advancement in the state of the art for energy-absorbing devices and changes in restraint philosophies for impact protection resulted from the efforts and experiences presented.
Various phases of the postflight testing of the command modules used in the Apollo Program are presented. The specific tasks to be accomplished by the task force recovery teams, the National Aeronautics and Space Administration Lyndon B. Johnson Space Center, (formerly the Manned Spacecraft Center) and the cognizant contractors/subcontractors are outlined. The means and methods used in postflight testing and how such activities evolved during the Apollo Program and were tailored to meet specific test requirements are described. Action taken to resolve or minimize problems or anomalies discovered during the flight, the postflight test phase, or mission evaluation is discussed.