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Viking '75 Spacecraft Design and Test Summary https://ntrs.nasa.gov/search.jsp?R=19810001592 2020-03-21T16:37:37+00:00Z NASA Reference Publication 1027 Viking '75 Spacecraft Design and Test Summary Volume I - Lander Design Neil A. Holmberg, Robert P. Faust, and H. Milton Holt NOVEMBER 1980 NBSA NASA Reference Publication 1027 Viking '75 Spacecraft Design and Test Summary Volume I Lander Design Neil A. Holmberg, Robert P. Faust, and H. Milton Holt Langley Research Center Hampton, Virginia fOI A National Aeronautics and Space Administration Scientific and Technical Information Branch 1980 PREFACE This publication, in three volumes, discusses the design of the Viking lander and orbiter as well as the engineering test program developed to achieve confidence that the design was adequate to survive the expected mission environ- ments and to accomplish the mission objective. Volume I includes a summary of the Viking Mission and the design of the Viking lander. Volume II consists of the design of the Viking orbiter and Volume III comprises the engineering test program for the lander and the orbiter. The material contained in this report was assembled from documentation pro- duced by the Martin Marietta Corporation (now Martin Marietta Aerospace) and the Jet Propulsion Laboratory during the Viking spacecraft design and test program. Viking Project personnel contributing to the preparation of this publication and their area of contribution are as follows: Lander science design and test ........... Joseph C. Moorman Lander guidance and control design and test ..... Anthony Fontana Lander propulsion design and test .......... Anthony Fontana Lander thermal design and test ........ T. W. Edmund Hankinson Viking orbiter detailed design information: Command and sequencing ............... Carl R. Pearson Computer command subsystem ............. Carl R. Pearson Flight data subsystem ............... Carl R. Pearson Data storage subsystem ............... Carl R. Pearson Visual imaging subsystem .............. Carl R. Pearson Infrared thermal mapper subsystem ........ Carl R. Pearson Mars atmospheric water detector subsystem ..... Carl R. Pearson Temperature control .............. William A. Carmines Structure subsystem .............. William A. Carmines Pyrotechnic subsystem ............. William A. Carmines Cabling subsystem ............... William A. Carmines Propulsion subsystem .............. William A. Carmines Mechanical devices subsystem .......... William A. Carmines Test data and information ............ William A. Carmines iii CONTENTS PREFACE .................................. iii INTRODUC TION ............................... ] VIKING MISSION SUMMARY .......................... ] MISSION CONSTRAINTS ........................... ] MISSION PHASES ............................. 2 MISSION ENVIRONMENTS .......................... 5 DESIGN AND TEST MANAGEMENT APPROACH ................... 6 System Definitions .......................... 6 System Interface Management ...................... 8 Design and Test Reviews ........................ 8 Problem Management .......................... 8 Schedules ............................... 8 VIKING LANDER DESIGN ........................... ] ] FIJNCTIONS AND REQUIREM_TS ....................... ]] Structures and Mechanisms Subs[stem .................. ]3 Thermal Control Subsystem ....................... ]3 Communications Subsystem ....................... ]3 Guidance and Control Subsystem .................... ]4 Power Subsystem ............................ 15 Propulsion Subsystem ......................... ]6 Pyrotechnics Subsystem ........................ ]6 Telemetry and Data Handling Subsystem ................. ]9 Science Subs[stem ........................... ]9 Entry Science ............................ ]9 Landed Science ........................... 20 SUBSYSTEM DESIGN ............................ 2] Structures and Mechanisms Subsystem .................. 2] Bioshield .............................. 2] Aerodecelerator ........................... 23 Lander Body Structure ........................ 25 Landing Legs ............................ 28 High-gain Antenna Deployment Mechanism ............... 29 Venting Assembly .......................... 30 Thermal Control Subsystem ....................... 33 Passive Thermal Control ....................... 33 Active Thermal Control ....................... 34 Operating Modes ........................... 35 Communications Subsystem . ...................... 37 Relay Communications Equipment ................... 37 Direct Communications System .................... 4] V Guidance and Control Subsystem .................... 63 Subsystem Design Concept ...................... 64 Components ............................. 98 Power Subs_{stem ........................... ] 05 Radioisotope Thermoelectric Generator ................ 1 05 Batteries .............................. ] 08 Bioshield Power Assembly ...................... ] ] ] Power Conditioning and Distribution Assembly ............ ] ] 7 Propulsion Subsystem ......................... 128 Pyrotechnics Subsystem ........................ 133 Lander Pyrotechnic Control Assembly ................. 135 Pyrotechnic Devices ......................... ] 37 Pyromechanical Devices ....................... 141 Pyrotechnics Subsystem Interfaces .................. ] 47 Telemetry and Data Handling Subsystem ................. 147 Engineering Data Collection ..................... ] 50 Science Data Collection ....................... 152 Data Storage ........................... 152 Data Storage Memory ......................... ] 52 Tape Recorder ............................ ] 53 Data Transmission .......................... ] 54 Science Subsystem ........................... 1 54 Entry Science ............................ 154 Landed Science ........................... 160 Aerospace Ground Equipment ..................... 182 APPENDIX - ABBREVIATIONS AND SYMBOLS ................... ] 95 REFER_qCE ................................. 207 vi INTRODUCT ION The Viking Project was initiated in ]968 and was climaxed with the launch- ing of two Viking spacecraft in ]975. The first landing on Mars was July 20, ]976, and the second landing was September 3, ]976. Each spacecraft contained an orbiter and a lander. The objective of the Viking Mission was to increase significantly man's knowledge of the planet Mars through orbital observations by the orbiter as well as by direct measurements made by the lander during Martian atmospheric entry, descent, and landing. Particular emphasis was placed on obtaining biological, chemical, and environmental data relevant to the exis- tence of life on the planet at the present time, at some time in the past, or the possibility of life existing at a future date. Orbiter observations con- sisted of radio-science, imaging, thermal, and water-vapor measurements used to assist landing-site selection and the study of the dynamic and physical charac- teristics of Mars and its atmosphere. Lander direct measurements consisted of radio science; atmospheric structure and composition; landing-site imaging; atmospheric pressure, temperature, and wind velocity; identification of the elemental composition of the surface material; physical properties of the sur- face material; the search for evidence of living organisms and organic materi- als; and determination of seismological characteristics of the planet. The Viking scientific return was further expanded by the capability of simultaneous Martian observations from orbit and the surface. This document, divided into three volumes, summarizes the design of the Viking lander and orbiter as well as the engineering test program developed to achieve confidence that the design was adequate to survive the expected mission environments and accomplish the mission objective. The engineering test program covered those aspects of testing prior to delivery of the Viking landers and orbiters to the John F. Kennedy Space Center. Most of the material contained in this document was taken from documentation prepared by Martin Marietta Corpora- tion (now Martin Marietta Aerospace) and the Jet Propulsion Laboratory during the Viking spacecraft design and test program. This volume contains a summary of the Viking Mission and a detailed description of the Viking lander design. All abbreviations and symbols used in this volume are defined in an appendix. Use of trade names in this report does not constitute an official endorse- ment of such products or manufacturers, either expressed or implied, by the National Aeronautics and Space Administration. VIKING MISSION SDq4MARY MISSION CONSTRAINTS The Viking spacecraft like all other NASA planetary spacecraft met the internationally established planetary quarantine requirement. The internation- ally accepted criterion for planetary quarantine is that there be only ] chance in 1000 (0.001 probability) of contamination by terrestrial organisms during the 50-year period beginning January 1, 1969. Becauseother spacecraft maybe exploring Mars during the 50-year period, the Viking sterilization requirements were more stringent: less than ] chance in 10 000 (0.000] probability). In order to avoid Earth organic contamination from invalidating Martian sample analysis, the lander surface sample and organic analysis instruments were cleaned and maintained such that surface samples would contain less than ] ppmof terrestrial organic material. MISSIONPHASES The five phases of the Viking mission, which are described in this section, were launch; cruise; orbital; separation, entry, and landing; and landed. Launch phase: Two Viking
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