'THE INTERPLANETARY 'PIONEERS VOLUME II: SYSTEM DESIGN AND DEVELOPMENT (NASA-SP-279-Vol-2) THE INTERPLANETARY PIONEERS. VOLUME 2: SYSTEM DESIGN AND DEVELOPMENT (NASA) 312 p MF. $0.95; SOD HC$2.5 N73-1788 CSCL 22C. N"' 73' 111/3 Unclas 62187 m0 I- U~~ NASA SP-279 THE INTERPLANETARY PIONEERS VOLUME II: SYSTEM DESIGN AND DEVELOPMENT by William R. Corliss Scientific and Technical Information Office 1972 NATIONAL AERONAUTICS AND SPACE ADMINISTRATION Washington, D.C. For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 Price $2.50 Stock Number 3300-0452 Library of Congress Catalog Card Number 74-176234 Foreword SOME EXPLORATORY ENTERPRISES start with fanfare and end with a quiet burial; some start with hardly a notice, yet end up significantly ad- vancing mankind's knowledge. The Interplanetary Pioneers more closely fit the latter description. When the National Aeronautics and Space Administration started the program a decade ago it received little public attention. Yet the four spacecraft, designated Pioneers 6, 7, 8, and 9, have faithfully lived up to their name as defined by Webster, "to discover or explore in advance of others." These pioneering spacecraft were the first to systematically orbit the Sun at widely separated points in space, collecting information on conditions far from the Earth's disturbing influence. From them we have learned much about space, the solar wind, and the fluc- tuating bursts of cosmic radiation of both solar and galactic origin. These Pioneers have proven to be superbly reliable scientific explorers, sending back information far in excess of their design lifetimes over a period that covers much of the solar cycle. This publication attempts to assemble a full accounting of this remarkable program. Written by William R. Corliss, under contract with NASA, it is organized as Volume I: Summary (NASA SP-278); Volume II: System Design and Development (NASA SP-279); and Volume III: Operations and Scientific Results (NASA SP-280). In a sense it is necessarily incomplete, for until the last of these remote and faithful sentinels falls silent, the final word is not at hand. HANS MARK Director Ames Research Center National Aeronautics and Space Administration III Contents Page Chapter 1. DEFINING THE PIONEER SYSTEM ..................... 1 Motivation for Pioneer ....................................... 1 Desiderata and Constraints: Some Early Thoughts ................. 2 A Hierarchy of Systems ................... 5...................5 A Model of the Spacecraft System ............................. 7 The Proper Order of Things .................................. 8 A Look at the STL Feasibility Study ............................. 10 Some Constraints on the Feasibility Study ........................ 11 A New Flight Concept ....................................... 12 Escaping the Earth's Gravitational Field ......................... 14 Communications Reliability ................................... 14 Getting Rid of Waste Heat ................................... 15 Onboard Data Storage ..................................... 15 An Early Weight Breakdown .................................. 15 Experiments Suggested by STL ................................ 16 Impact of the Feasibility Study ................................ 17 Reference ................. ............................... 17 Chapter 2. PIONEER LAUNCH TRAJECTORY AND SOLAR ORBIT DESIGN. 19 Specific Mission Objectives: A Scientist's View .................... 19 Other Factors Involved in Pioneer Trajectory and Orbit Design ....... 20 Pioneer 9 Trajectory Analysis ................................. 27 Pioneer Orbit Parameters .................................... 34 Spacecraft Orientation ...................................... 35 Reference ................. ............................... 38 Chapter 3. SPACECRAFT DESIGN APPROACH AND EVOLUTION ..... 39 Spacecraft Design Approach ................................. 39 Evolution of the Spacecraft Design ............................. 49 References ................................................. 53 Chapter 4. THE SPACECRAFT SUBSYSTEMS ...................... 55 The Communication Subsystem ................................ 55 The Data Handling Subsystem ................................ 68 The Command Subsystem .................................... 91 The Electric Power Subsystem ................................. 100 PRECED G' A -':.....,;-:i L..i :."' VI THE INTERPLANETARY PIONEERS Page The Orientation Subsystem ................................... 111 The Thermal Control Subsystem .............. ............... 121 The Structure Subsystem ..................................... 128 Overall Weight Breakdown .................................. 134 References ................................................ 136 Chapter 5. SCIENTIFIC INSTRUMENTS ........................... 137 Scientific Objectives ..................... ................... 137 Applications of Pioneer Data ................................. 139 Instrument Interfaces and Specifications ......................... 139 Instrument Selection ...................................... .. 140 The Goddard Magnetometer (Pioneers 6, 7, and 8) ............... 142 The Ames Magnetometer (Pioneers 9 and E) ..................... 145 MIT Faraday-Cup Plasma Probe (Pioneers 6 and 7) .............. 148 Ames Plasma Probe (Pioneers 6, 7, 8, 9, and E) .................. 152 The Chicago Cosmic Ray Experiment (Pioneers 6 and 7) ........... 160 The GRCSW Cosmic Ray Experiments (Pioneers 6, 7, 8, 9, and E) ..... 165 Minnesota Cosmic Ray Detector (Pioneers 8, 9, and E) ............. 170 The Stanford Radio Propagation Experiment (Pioneers 6, 7, 8, 9, and E) ................................................. 171 The TRW Systems Electric Field Detector (Pioneers 8, 9, and E) ...... 176 The Goddard Cosmic Dust Experiment (Pioneers 8, 9, and E) ....... 181 The JPL Celestial Mechanics Experiment (Pioneers 6, 7, 8, 9, and E).. 188 References ................................................ 188 Chapter 6. THE PIONEER TEST AND GROUND SUPPORT PROGRAM... 191 Test Specifications .......................................... 192 Spacecraft Models ......................................... 192 Test Facilities .............................................. 196 Spacecraft Integration and Test Procedures ..................... 202 Electrical Ground Support Equipment ........................... 205 Typical Test Results ......................................... 207 References ................................................ 210 Chapter 7. THE DELTA LAUNCH VEHICLE ........................ 211 Why the Delta2. ............................................ 211 The Evolution of the Delta .................................... 211 The Delta Spacecraft Interface ............................... 216 Other Interfaces ........................................... 224 Trajectory Design .......................................... 224 Primary Launch Objectives ................................... 229 The Launch Sequence ....................................... 231 CONTENTS VII Page A Typical Weight Breakdown ................................ 235 References ................................................ 236 Chapter 8. TRACKING AND COMMUNICATING WiTH PIONEER SPACECRAFT ...................................... 237 Tracking the First Pioneers ................................... 237 Some Generalities About Tracking and Data Acquisition ........... 239 General Deep Space Network Capabilities ..................... 241 Specific Pioneer Network Configurations ........................ 263 Telemetry Capabilities ...................................... 267 Command Capabilities ...................................... 267 References ................................................ 273 Chapter 9. PIONEER DATA-PROCESSING EQUIPMENT .............. 277 Pioneer Off-Line Data-Processing System ....................... 277 Tape Processing Station ..................................... 278 Pioneer Off-Line Direct-Coupled System ........................ 280 Data Processing at TRW Systems .............................. 283 Reference ................................................ 283 BIBLIOGRAPHY .............................................. 285 PIONEER SPECIFICATIONS ..................................... 289 Appendix. RELIABILITY AND QUALITY ASSURANCE ................ 293 CHAPTER 1 Defining the Pioneer System MOTIVATION FOR PIONEER HE SCIENTIFIC MISSION of Pioneers 6 through 9 was the synoptic measurement of the interplanetary milieu as it is affected by the Sun. The Pioneers measured and transmitted back to Earth data on solar plasma, cosmic radiation, magnetic and electric fields, and the specks of cosmic dust that drift through interplanetary space. All of these physical phenom- ena are dominated by the Sun. The Pioneer spacecraft described here were akin to weather satellites, except that they were artificial planets of the Sun rather than satellites of the Earth. Spotted strategically around the Sun in the plane of the ecliptic, they monitored the ever-changing fluxes and fields that wax and wane with solar activity. Solar activity follows an eleven-year cycle of sunspot numbers-a periodic phenomenon felt throughout the solar system. In 1962, when NASA began to formulate its "follow-on" Pioneer Program, which would extend the earlier International Geophysical Year (IGY) Pioneers (Pio- neers 1-5), scientists around the world were organizing an investigation of solar problems to take place during the solar minimum expected