Lunar Surface Exploration
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Bendix Technical Journal The Bendix Technical Journal publishes noteworthy results of scientific and engineering work accomplished by the people of The Bendix Corporation. EDITORIAL STAFF Joseph Rutkowski, Editor Lenore R. Stevens, Associate Editor Barbara E. Waterbury, Secretary to .the Editors ADVISORY BOARD E. C. Johnson, Chairman J. H. Leggett R. E. Esch J. B. Tierney W. E. Kock A. B. Van Rennes L. J. Larsen L. B. Young TECHNICAL CONSULTANTS for this Issue B. J. Rusky, Issue Coordinator Aerospace Systems Division P. S. Curry Aerospace Systems Division E. S. VanValkenburg Aerospace Systems Division The cover photograph of the Apollo 15 Lunar Surface Experi ments Package was made by Astronauts David Scott and Jim Irwin prior to lift-off from the lunar surface. Published three times a year by The Bendix Corporation. A. P. Fontaine, Chairman and Chief Executive Officer; W. M. Blumenthal, President and Chief Operating Officer. Sub scriptions: $5.00 per year; individual copies: $2.00. Address all correspondence to: The Editor, Bendix Technical Journal, The Bendix Corporation Executive Offices, Bendix Center, Southfield, Michigan 48076. ©copyright 1971 by The Bendix Corporation. The material in this Journal may be reproduced in whole or in part provided that the source is acknowledged. Microfilmed by University Microfilms, Inc., 301 North Zeeb Road, Ann Arbor, Michigan 48106. BENDIX TECHNICAL JOURNAL LUNAR SURFACE EXPLORATION CONTENTS Volume 4 Number 2 Summer/Autumn 1971 GUEST EDITORIAL iii Colonel James A. McDivitt PAPERS ALSEP: The Scientific Voice of the Moon L. R. Lewis Some Aspects of ALSEP Structural/Thermal Design 11 J. L. McNaughton The ALSEP Central Station Data Subsystem 20 W.M. Tosh The Passive Seismic Experiment 28 D. K. Breseke and J. Lewko, Jr. The Active Seismic Experiment 40 J. R. McDowell The Charged-Particle Lunar Environment Experiment 52 A. D. Robinson and L. D. Ferguson The Lunar Heat Flow Experiment 64 B. D. Smith The Laser-Ranging Retroreflector 81 J. M. Brueger ALSEP Human-Engineering Design Criteria 94 R. L. Redick ALSEP Data Management 100 C. R. Murtaugh, W. K. Stephenson, and B. L. Sharpe NOTES The Lunar Ejecta and Meteorites Experiment 109 L. Galan The Lunar Mass Spectrometer Experiment 114 R. D. Ormsby and C. E. DeHaven, Jr. The Lunar Seismic Profiling Experiment 118 J.E.Dye The Lunar Surface Gravimeter Experiment 122 H. K. Hsi and W. E. Crosmer AUTHORS 127 KEY TO ABBREVIATIONS AND ACRONYMS 131 Future Issues: Pollution Detection and Control Image Data Processing Automation GUEST EDITORIAL James A. McDivitt Colonel, United States Air Force Manager, Apollo Spacecraft Program Office NASA Manned Spacecraft Center The Apollo program, which has taken man further in his exploration of his surroundings than any previous endeavor in history, began with a spark of imagination in 1959. It was obvious that this spark would ignite an expansive family of technical and engineering innovations required to accomplish such a feat. Much has been discussed and published regarding the extraordinary nature of the Apollo vehicle and booster programs, the related operations facilities, and the associated philosophical and social issues. There is one area in particular, however, that very clearly and distinctively underlines the basic intent of the Apollo program, that demonstrates the inventiveness sparked by the program, and that is even now providing a wealth of knowledge, the impact of which will extend far into the history of man. This area is the scientific exploration of the lunar surface implemented by the Apollo Lunar Surface Experiments Package, commonly referred to as ALSEP. At the outset of the Apollo program, it was quickly recognized that - in addition to the attention that would necessarily be focused on transportation systems -- attention should be given to the development of methods and equipment for detailed lunar exploration and evaluation. The major goal was a completely self-contained science station to be deployed and activated by the Apollo astronauts and left to operate on the lunar surface for some time after astronaut departure. During the initial years of the program, many concepts were reviewed and many potential instruments evaluated. These actions resulted in the basic definition of the ALSEP. It is easy to imagine the variety of issues that required recognition, the problems that had to be solved, and the inventiveness that was required to provide and operate an ALSEP. How, for example, was a complex system of experiments to be contained and located in the Apollo vehicles for transportation? How could instruments be constructed to operate for extensive periods on the lunar surface in the face of extreme temperature variations and limited size and power? How could these same instruments be made easily deployable by the astronauts? How was electric power to be generated to permit the system to operate for years? These and many other questions have been successfully answered by combining the wealth of experience gained in past development programs with new techniques developed specifically for the ALSEP program. The ALSEP has now been completed and demonstrated. The system was conceived, designed, developed, fabricated, and put into operation on the moon's surface within very little more than three years after the actual start of hardware development. Although the original experiments package was intentionally limited in size and complexity to be consistent with the objectives of the Apollo 11 mission, it provided history-making insight into the lunar environment and structure. The full-sized packages emplaced on the Apollo 12, 14, and 15 missions have since provided an absolutely unprecedented amount of information concerning lunar atmosphere, magnetic fields, particle and plasma impingement, physical structure, and meteorite impacts. These ALSEP systems have also verified that such equipment can be produced to operate over very long periods of time in extremely severe environments. Although the Apollo 11 system was required to operate for only one lunar day, it did in fact continue to operate for four and one-half months. The Apollo 12 system, designed to operate for up to one year, is still providing data. The Apollo 14 and Apollo 15 systems are also performing with no operational problems. With the additional ALSEP systems planned for the Apollo 16 and 17 flights, it should be possible to develop a relatively complete picture of the moon, its surroundings, and its relationships to the earth and the sun. This network of instruments, emplaced in various locations on the front face of the moon, will once again demonstrate man's capability to implement his most imaginative ideas and to continue to expand his knowledge of the universe. BENDIX TECHNICAL JOURNAL SUMMER/AUTUMN 1971 iii ALSEP: The Scientific Voice of the Moon L. R. LEWIS A network of scientific stations is today continuously relaying long-term science data to earth from the lunar surface. The data are transmitted from scientific experiments deployed on the moon as a part of Apollo missions 12, 14, and 15. Similar packages are to be deployed on Apollo missions 16 and 17. This paper presents an overview of Apollo Lunar Surface Experiments Package (ALSEP) design and development, with particular emphasis on con straints imposed on the system and on those aspects ofALSEP design that are unique to this system among space systems. The status of experiments deployed on Apollo missions 12 and 14 is discussed briefly. The individual experiments are described in detail in subsequent papers. INTRODUCTION The objectives of lunar surface exploration as it March 1966, we at this facility were selected by the was to be carried out as a part of the Apollo program NASA Manned Spacecraft Center as prime contractor were defined by the National Academy of Sciences for the design, integration, test, and systems manage Space Science Board and by National Aeronautics ment of the scientific exploration system known as and Space Administration Lunar Exploration and the Apollo Lunar Surface Experiments Package Science Conferences during the time period 1963 to (ALSEP). ALSEP instruments are carried to the 1965. The activity assigned highest priority for early moon on the Apollo spacecraft and set up on the Apollo landings was the collection of the greatest lunar surface by the Apollo crew. Using a self feasible number and variety of lunar samples. Second contained power supply and communications equip in priority was the emplacement of lunar surface ment, each ALSEP collects and transmits to earth observatories for long-term scientific investigation. scientific and engineering data for extended periods The basic science data to be obtained by the observa of time following astronaut departure. The system tories were to define has flown on Apollo 12 and all subsequent missions. • the internal structure and composition of the A variation of the ALSEP, known as the Early moon; Apollo Scientific Experiments Package (EASEP), was • heat flow from the lunar interior; flown on Apollo II, the first flight to land on the • tectonic processes and meteorite impacts, with moon. Deployment of this package, an abbreviated an assessment of their importance in the genesis version of the ALSEP, is shown in Figure 1; it differs of surface features; from the ALSEP in that solar panels were used in • near-surface geologic structure; place of a radioisotope thermoelectric generator • the existence and nature of the moon's magnetic (RTG) to generate electric power, and simplified