IMP Series Report/Bibliography

IMP Series Report/Bibliography DECEMBER 1971 n,<,t, t * ? * ' 1 ! S' NATIONAL SPACE SGIENCE D&FA CENTER NATIONAL AERONAUTICS AND SPACE ADMINISTRATION - GODDAR0 SPACE FLIGHT CENtER, NSSDC 71-21 IMP SERIES REPORT/BIBLIOGRAPHY Prepared By Joseph H. King National Space Science Data Center Goddard Space Flight Center National Aeronautics and Space Administration Greenbelt, Maryland 20771 December 1971 Page intentionally left blank FOREWORD The National Space Science Data Center (NSSDC) has been charged with the tasks of acquiring space science data from satellite experiments and of making the acquired data^ along with adequate documenta- tion, available to members of the space science community for further scientific study. In fulfilling these tasks, NSSDC has become an information center as well as a data center. This document, containing the scientific results of and information about the Interplanetary Monitoring Platform (IMP) spacecraft series, has been generated using the NSSDC information base and, particularly, the Technical Reference File (TRF) maintained at NSSDC. The TRF is a part of the NSSDC information base and contains references to published papers and unpublished reports related to space science experiments. Some of the spacecraft-related information presented here was provided to NSSDC by IMP project personnel at Goddard Space Flight Center at the time of the generation of this document. For this we are grate- ful. We would also like to acknowledge the cooperation of personnel in the IMP Project Office and of those IMP experimenters who reviewed pre- liminary versions of the spacecraft and experiment descriptions and the bibliographic entries and abstracts in December of 1970. It is anticipated that subsequent editions of this IMP report will be published as sufficiently more published papers using IMP data become available. iii Page intentionally left blank CONTENTS FOREWORD ill I. INTRODUCTION 1 II. SPACECRAFT 3 Nomenclature 3 General Characteristics 3 Spacecraft Attitude 4 Time Coverage 5 Spatial Coverage 5 Bibliography and Abstracts for Spacecraft-Related Papers 11 IMP A ll IMP B 14 IMP C , 15 IMP D 16 IMP E 19 IMP F 20 IMP G 22 III. EXPERIMENTS 23 General Information 23 Brief Descriptions of IMP Experiments 34 Magnetic Field Experiments 34 Electric Field Measurements 39 Plasma Experiments ...; 40 Energetic Particle Experiments 48 Other Experiments 68 Bibliography and Abstracts for Experiment-Related Papers . 1 70 Magnetic Field Experiments 70 Plasma Experiments , 134 Energetic Particle Experiments 155 Other Experiments 236 INDEXES , ; 237 Index to Abstracts and Brief Descriptions 239 Index to Authors 241 LIST OF TABLES Table Title Page 1 IMP Spacecraft Names and Launch Dates 3 2 IMP Spacecraft Spin Directions and Rates 5 3 IMP Spacecraft Orbital Parameter Variations 8 4 IMP Spacecraft Values of a and 3 10 5 IMP Experiments Grouped by Phenomenon Measured .. 24 6 Co-Investigators for IMP Experiments 28 7 IMPs A - G Experiment Summary 29 LIST OF FIGURES Figure title Page 1 IMP Spacecraft Data Coverage 6 2 IMP D Spacecraft Orbital Parameters 7 3 IMP Spacecraft Local Time Apogee 9 4 IMPs A - G Magnetic Field Data Coverage 30 5 IMPs A - G Plasma Data Coverage 31 6 IMPs A - G Proton and Electron Count Rate Data Coverage 32 vi I. INTRODUCTION Through detailed measurements of the near interplanetary environ- ment, the IMP series of spin-stabilized spacecraft has been highly suc- cessful in furthering our understanding of solar-terrestrial physics. Nearly continuous interplanetary measurements of magnetic fields j plas- mas, and energetic solar and galactic particles have been obtained since November 1963; solar X-ray data have been obtained since July 1966. In addition, measurements taken in distant magnetospheric regions, the bow shock, the magnetosheath, the magnetopause, and the magnetotail have been crucial to our understanding of those regions. It is the purpose of this document to summarize the main characteristics of the IMP spacecraft and experiments from a scientific rather than technological point of view and to present the scientific knowledge gained from this series of spacecraft in the form of abstracts of scientific papers using IMP data. The document is divided into two parts. In the first part, spacecraft characteristics, including temporal and spatial coverages, are presented and are followed by a bibliography containing abstracts from spacecraft-related papers. In the second part, experiments on all IMPs (including prelaunch IMPs -H and -J) are described. Figures are presented showing the time histories, through the end of 1970, of magnetic field, plasma, and energetic particle experiments. A bibliography containing abstracts is presented for each experiment on each spacecraft from IMP A through IMP G. Wherever possible, the abstracts given here for spacecraft- and experiment-related papers are by the originating authors. II. SPACECRAFT Nomenclature Because the entire IMP series of spacecraft is a subset of the Explorer series and; because two of the IMPs were to have been anchored to a lunar orbit, the names of.the IMP spacecraft may be somewhat con- fusing. For clarification, a list of names and launch dates is presented in Table 1. Table 1 - IMP Spacecraft Names and Launch Dates IMP Explorer IMP AIMP AIMP Launch (UT) A 18 1 11/27/63 B 21 2 10/04/64 C 28 3 05/29/65 D 33 D 1* 07/01/66 E 35 E 2** 07/19/67 F 34 4 05/24/67 G 41 5 06/21/69 I 43 6 03/13/71 H planned 72 J planned 73 *Lunar orbit intended but not achieved. **Lunar orbit achieved. Before launch, IMP spacecraft are known by their letter codes; after launch, an Explorer number and an IMP (or AIMP) number is assigned. In many cases, a spacecraft is referred to by its prelaunch designation even after launch. Because the prelaunch designations, constitute the most continuous sequence of names in the IMP series, reference to indi- vidual spacecraft by their prelaunch designations is made throughout this report. General Characteristics The IMP spacecraft have been grouped here by their characteristics, with IMPs A, B, C, D, and E forming one group, IMPs F and G another, and IMPs I, -H, and -J a third. IMPs A through E shared numerous characteristics. Each weighed about 62 kg and utilized about 38 w average power provided by solar cells and chemical batteries. Slight differences existed among indi- vidual spacecraft. Exclusive of appendages (antennas, experiment booms, etc.), each spacecraft was shaped as an octagonal drum 71 cm across; IMPs A through C were about 30.5 cm high, while IMPs D and E were only 18 cm high. Each spacecraft except IMP D carried seven active experiments; IMP D carried six active experiments. The PFM data telemetry bit rate was increased from about 10 bps on IMPs A, B, and C to about 28 bps on IMPs D and E. Of. these spacecraft, IMP E continues to operate. IMPs F and G were more complex than IMPs A through E, carrying 11 and 12 active experiments, respectively. Their configurations and their power consumptions were similar to those of the IMPs A through C. They weighed 74 and 80 kg, respectively, and the telemetry bit rate for both was 100 bps. IMP F entered the earth's atmosphere in May 1969; IMP G continues to operate. IMP I represents the most significant increase in complexity in the IMP series. This spacecraft is a 16-sided drum, 135 cm across and 183 cm high. It weighs about 278 kg, uses about 110 w average power, and has a 1600-bps data telemetry rate. It carries 12 active experiments. IMPs -H and -J will be similar in configuration to IMP I. Spacecraft Attitude All IMP spacecraft were spin stabilized and used an optical aspect system for determining spin rate, spin phase, and spin axis direction. In addition, each spacecraft beginning with IMP D had a sun pulse gen- erator to yield spin phase information required for the onboard sector- ing of data on some experiments. The optical aspect systems and the sun pulse generators worked well throughout the useful life of each IMP, except on IMP F (failure occurred 2 months before spacecraft reentry). The intended spin axis directions were achieved within reasonable limits for each IMP except IMP B. The spin axis of IMP D lay approximately in the ecliptic plane, while the spin axes of IMPs E, G, and I are approximately normal to the ecliptic plane, as was the spin axis of IMP F. Table 2 indicates the ranges, in degrees, over which the IMP spin axes have varied in the customary inertial earth-equatorial coordinate system. Also included in Table 2 are the corresponding angular ranges in inertial ecliptic coordinates. The two coordinate systems share a common X axis (i.e. , from the earth to the sun at the time of the vernal equinox). Note that the declination angle, in ecliptic coordinates, measures the extent to which the spin vector lies outside of ecliptic plane. Table 2 also shows the approximate limits within which the IMP spin rates have varied over spacecraft lifetimes. Table 2 - IMP Spacecraft Spin Directions and Rates Right Right Ascension Declination Ascension Declination (equatorial) (equatorial) (ecliptic) (ecliptic) Spin Rate IMP (deg) (deg) (deg) (deg) (rpm) A 117 to 107 -24 to -31 111 to 125 -44 to -52 22.0 to 25.8 B 44 to 49 47 to 58 57 to 62 29 to 39 14.4 to 18.0 C 65 to 77 - 9 to -14 61 to 74 -32 to -36 17.4 to 27.5 D 215 to 246 -21 to -15 219 to 258 - 6 to 15 17.5 to 26.5 E 74 to 107 -55 to -73 0 to 360 -83 to -89 24.5 to 26.4 F 79 to 95 -62 to -69 0 to 360 -83 to -89 23.2 to 22.5 G 103 to 119 -61 to -68 156 to 206 -78 to -85 27.5 to 27.0 I* 90 -66 -90 5.4 — *The angles are nominal initial values; the spin rate is as observed.

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