NASA Office of Logic Design

NASA Office of Logic Design

A scientific study of the problems of digital engineering for space flight systems,
with a view to their practical solution.

Some Apollo Experience Reports

Electronic Systems Test Program Accomplishments and Results

Thomas E. Ohnesorge
Manned Spacecraft Center, NASA
March, 1972
NASA Technical Note TN D-6720

This document presents a chronological record of the Electronic Systems Test Program from its conception in May 1963 to December 1969. The original concept of the program, which was primarily a spacecraft/Manned Space Flight Network communications system compatibility and performance evaluation, is described. The evolution of these concepts to include various levels of test detail, as well as systems-level design verification testing, is discussed. Actual implementation of these concepts is presented, and the facility to support the program is described. Test results are given, and significant contributions to the lunar landing mission are underlined. Plans for modifying the facility and the concepts, based on Apollo experience, are proposed.

Lunar Module Display and Control Subsystem

Andrew J. Farkas
Manned Spacecraft Center, NASA
March, 1972
NASA Technical Note TN D-6722

The lunar module display and control subsystem equipment is described, with emphasis on major problems and their solutions. Included in the discussion of each item is a description of what the item does and how the item is constructed.  The development, hardware history, and testing for each item are also presented.

Reliability and Quality Assurance

K. P. Sperber
Manned Spacecraft Center, NASA
September, 1973
NASA Technical Note TN D-7438

The reliability of the Apollo spacecraft resulted from the application of proven reliability and quality techniques and from sound management, engineering, and manufacturing practices. Continual assessment of these techniques and practices was made during the program, and, when deficiencies were detected, adjustments were made and the deficiencies were effectively corrected. The most significant practices, deficiencies, adjustments, and experiences during the Apollo Program axe described in this report. These experiences can be helpful in establishing an effective base on which to structure an efficient reliability and quality assurance effort for future space-flight programs.

Oboard Navigational and Alignment Software

Robert T. Savely and Bedford F. Cockrell
Manned Spacecraft Center, NASA
Samuel Pines, Analytical Mechanics Associates
March, 1972
NASA Technical Note TN D-6741

The onboard navigational and alignment routines used during the nonthrusting phases of an Apollo mission are discussed as to their limitations, and alternate approaches that have more desirable capabilities are presented. This discussion includes a more efficient procedure for solving Kepler's equation, which is used in the calculation of Kepler's problem and Lambert's problem; and a sixth-order predictor (no corrector used) scheme with a Runge-Kutta starter is recommended for numerical integration. Also evaluated are the extension of the rendezvous navigation state to include angle biases and the use of a fixed coordinate system. In general, the discussion reflects the advancement of the state of the art since the design of the Apollo software.

Abort Planning

Charles T. Hyle, Charles E. Foggatt, and Bobbie D. Weber
Manned Spacecraft Center, NASA
NASA Technical Note TN D-6847
June 1972

Definition of a practical return-to-earth abort capability was required for each phase of an Apollo mission. A description of the basic development of the complex Apollo abort plan is presented in this paper. The process by which the return-to-earth abort plan was developed and the constraining factors that must be included in any abort procedure are also discussed. Special emphasis is given to the description of crew warning and escape methods for each mission phase.

The Docking System

Robert D. Langley
Lyndon B. Johnson Space Center, NASA
NASA Technical Note TN D-6854
June 1972
tn-d6854_apollo_docking _system.pdf

The decision to accomplish the lunar landing mission by use of the lunar orbit rendezvous technique required that a docking system be developed to allow (1) spacecraft modules to be structurally joined, (2) intravehicular transfer of the crew and equipment, and (3) separation of the modules. The basic design criteria of the docking system, the evolution process, and the various docking concepts considered for the Apollo Program are presented. Docking systems that were considered for the Apollo Program included both impact and nonimpact systems; a probe and drogue impact system was selected. Physical and functional descriptions of the probe and drogue, the crew transfer tunnel, and docking ring latches are presented for both the early configuration and the present configuration as influenced by the development and qualification test programs. In addition, preflight checkout activity and mission performance of the system are discussed.

Certification Test Program

Joseph H. Levin and Bill J. McCarty
Manned Spacecraft Center, NASA
NASA Technical Note TN D-6857
June 1972

A review of the Apollo Spacecraft Certification (qualification) Test Program is presented. The approach to devising the spectrum of dynamic and climatic environments, the formulation of test durations, and the relative significance of the formal certification test program compared with development testing and acceptance testing are reviewed. Management controls for the formulation of test requirements, test techniques, data review, and acceptance of test results are considered. Significant experience gained from the Apollo Spacecraft Certification Test Program which may be applicable to future manned spacecraft is presented.

Apollo Experience Report - Launch Escape Propulsion Subsystem

Neil A. Townsend
Manned Spacecraft Center, NASA
March, 1973
NASA Technical Note TN D-7083

The Apollo launch escape propulsion subsystem contained three solid rocket motors. The general design, development, and qualification of the solid-propellant pitch-control, tower- jettison, and launch-escape motors of the Apollo launch escape propulsion subsystem were completed during the years 1961 to 1966. The launch escape system components are described in general terms, and the sequence of events through the ground-based test programs and flight-test programs is discussed. The initial ground rules established for this system were that it should use existing technology and designs as much as possible. The practicality of this decision is proved by the minimum number of problems that were encountered during the development and qualification program.

Guidance and Control Systems: Command and Service Module Stabilization and Control System

Orval P. Littleton
Lyndon B. Johnson Space Center, NASA
NASA Technical Note TN D-7785
September 1974

The concepts, design, development, testing, and flight results of the command and service module stabilization and control system are discussed. The period of time covered is from November 1961 to December 1972. Also included are a functional description of the system, a discussion of the major problems, and recommendations for future programs.

Spacecraft Pyrotechnic Systems

M.J. Falbo and R.L. Robinson
March 1973

Pyrotechnic devices were used successfully in many systems of the Apollo spacecraft. The physical and functional characteristics of each device are described.  The development, qualification, and performance tests of the devices and the ground-support equipment are discussed briefly.  Recommendations for pyrotechnic devices on future space vehicles are given.

Command and Service Module Electrical Power Distributions System

R. E. Munford and B. Hendrix
March 1974

A review of the design philosophy and development of the Apollo command and service modules electrical power distribution subsystem, a brief history of the evolution of the total system, and some of the more significant components within the system are discussed. The electrical power distribution primarily consisted of individual control units, interconnecting units, and associated protective devices. Because each unit within the system operated more or less independently of other units, the discussion of the subsystem proceeds generally in descending order of. complexity; the discussion begins with the total system, progresses to the individual units of the system, and concludes with the components within the units

Command and Service Module Reaction Control System

R. J. Taeuber and D.P. Weary
June 1974

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.

Apollo Digital Autopilot Design and Development

K.J. Cox and W.H. Peters
June 1973

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