Observations of the interplanetary medium - Vela 3 and IMP 3, 1965-1967
Interplanetary plasma and magnetic field observations by Vela 3 and Imp 3 satellites
Bame, S. J.↗
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The IMP-H ion composition experiment
A compact mass energy spectrometer to be flown aboard the IMP-H spacecraft is described. Scientific aims include determination of the relative and absolute fluxes of He-4(2+), He-4 (+), 0(6+), and 0(7+), and He-3(2+).
Acuna, M. H.↗
Solar bus regulator and battery charger for IMP's H, I, and J
Interplanetary Monitoring Probe (IMP) spacecrafts H, I, and J utilize a direct energy transfer (DET) type of power system operating from a solar array source. A shunt type of regulator prevents the bus voltage from exceeding a preset voltage level. The power system utilizes a single differential amplifier with dual outputs to control the battery charge/shunt regulator and the discharge regulator. A two-voltage level, current limited, series charger and a current sensor control battery state of charge of the silver-cadmium battery pack. Premature termination of the battery charge is prevented by a power available gate that also initiates charge current to the battery upon availability of excess power.
Paulkovich, J.↗
IMP F and G phase 1 magnetic field analysis
The program developed to analyze magnetic field data from the magnetic field experiment flown in IMP F is reported. The analysis converts the raw X, Y, Z sensor data as received on the magnetic field experiment tape into vector measurements of the ambient magnetic field observed by the experiment. These data are computed for four frames of reference -- apparent, payload, solar ecliptic and solar magnetospheric. In addition 20.45 second statistics are computed for the last three coordinate systems. Finally, a summary tape is produced containing detailed data and sequence statistics as well as the output from the autocorrelation computer, trajectory data and identification information.
Mish, W. H.↗
IMP-I spacecraft final magnetic tests
The increased IMP-I spacecraft spin axis moment resulting from excessive field exposures during environmental testing substantiated the need for a final pre-launch magnetic deperm and measurement. By performing a dc rotation deperm it was possible to reduce this moment below the previous initial test post deperm magnitude. In addition, the magnetic field disturbance at the flight magnetometer diminished to below 0.1 nanotesla (gamma) in all directions.
Harris, C. A.↗
Recent probe measurements of dc electric fields from IMP 1
The measurement of dc electric fields in the magnetosphere by IMP 1 are presented. Electric fields on the order of 1 mV/m in the solar wind, with about a 40% jump at the bow shock were observed. Observational results are graphed.
Aggson, T. L.↗
Magnetospheric substorms in the distant magnetotail observed by Imp 3.
Study of variations of the magnetic field and plasma sheet in the distant magnetotail (20 to 40 earth radii) during magnetospheric substorms on the basis of the Imp 3 magnetic-field and particle data. Depending on the locations of the satellite with respect to the boundary of the plasma sheet, the variations differ greatly. However, the present results and the results of other workers give a clear indication of an increase of the magnitude of the field outside the plasma sheet and of the simultaneous ?thinning' of the plasma sheet during an early phase of substorms. At about the maximum epoch or during the recovery phase of substorms, the plasma sheet expands and appears to be inflated to at least the presubstorm level. Furthermore, a large excessive flux of the magnetic (approximately equal to Z component) field, as compared with the flux of the original dipole field, appears across the neutral sheet.
Meng, C. I.↗
Imp 5 magnetic-field measurements in the high-latitude outer magnetosphere near the noon meridian.
Results of Imp 5 magnetic-field measurements at geomagnetic latitudes up to 75 deg and at distances beyond six earth radii, revealing the permanent existence of a broad depressed field region centered on the polar or dayside cusp. Field strengths at seven earth radii on cusp field lines that connect to the earth are typically only 50 to 70% of that of an undistorted dipole field. The transition region between the magnetosheath and the point where the fields are clearly of dipolar origin is characterized by large-amplitude fluctuations and the lack of a clear magnetopause boundary. Magnetic-field perturbations are observed in the cusp region with magnitudes up to 45 gamma and in directions that are approximately perpendicular to the average field. These perturbations are suggestive of field-aligned currents, and their magnitudes are consistent with the low-altitude measurements obtained on polar-orbiting spacecraft.
Fairfield, D. H.↗
Relativistic electrons from the sun observed by IMP-4.
Evaluation of data obtained from the IMP-4 satellite concerning 0.3- to 12-MeV electrons from the sun between May 24, 1967, and May 2, 1969. Correlations with contemporary proton intensity increases at energies above 1 MeV are studied. The results of this study are the following: (1) the differential electron energy spectrum (0.3 to 12 keV) from solar flares appears to be a constant of the flare process, with the spectral index gamma = (-) 3.0 plus or minus 0.2; (2) particle emission from solar flares contains a prompt component, which is injected into the interplanetary medium beyond the sun and which is responsible for the diffusion characteristics of solar particle events, and a delayed component which is effectively contained in the lower solar atmosphere where it diffuses typically less than or equal to plus or minus 100 deg in longitude and gradually escapes into interplanetary space; the delayed component gives rise to the corotating features commonly observed after the impulsive and diffusive onset from the prompt component; (3) storage of electrons greater than 300 keV and protons greater than 1 MeV is essential to explain emission and propagation characteristics of solar particle events; and (4) the events with low proton/electron ratios all occur at least three weeks after the previous relativistic electron producing flare.
Simnett, G. M.↗
Tesseral resonance on Imp 4 orbit.
The supersynchronous resonance occurred because the orbital period of 4 1/3 days was nearly commensurate with the earth's rotational period. The satellite was launched on May 24, 1967. The perturbation due to commensurability is discussed, giving attention to the ground track of the longitude at perigee passage and the effect of the tesseral harmonic on the time of perigee passage. The measurement of the time of perigee passage of Imp 4 is accurate enough to provide a stringent test of the third-degree tesseral terms in the model of the earth's gravitational field.
Lowrey, B. E.↗
IMP mission
The program requirements and operations requirements for the IMP mission are presented. The satellite configuration is described and the missions are analyzed. The support equipment, logistics, range facilities, and responsibilities of the launching organizations are defined. The systems for telemetry, communications, satellite tracking, and satellite control are identified.
Source record↗
Delta-90 Interplanetary Monitoring Platform-H (IMP-H)
The operations summary for the IMP-H spacecraft is presented. The subjects discussed are: (1) mission objective, (2) description of launch vehicle and spacecraft, (3) mission plan, (4) flight plan, and (5) post launch operations. Details of the mission are presented in drawings and tables of data.
Source record↗
Delta-90 Interplanetary Monitoring Platform-H (IMP-H) flash flight report
The Delta-90 launch vehicle and the IMP-H spacecraft were successfully launched from Pad B, Complex 17, Cape Kennedy Air Force Station, Florida, at 2120:00.559 EDT on September 22, 1972. The countdown proceeded smoothly to liftoff with no major difficulties or unscheduled holds. The Delta-90/IMP-H were launched on a pad azimuth of 115 degrees, the vehicle ten rolled to 95 degrees from the north placing the spacecraft in a highly elliptical transfer orbit. Firing the spacecraft kickmotor at 1136 EDT, September 25, 1972, injected the spacecraft into its final desirable near-circular orbit approximately half way between the planet earth and its moon. Vehicle performance of all stages appeared nominal with all sequenced events occurring at the expected times. Data acquisition from all range stations was very good. Damage to the launch pad caused by liftoff was nominal.
Source record↗
Processing and analysis of data from the University of Chicago experiments on the IMP 4 and 5 spacecraft
Data from the Charged Particle Experiments of the IMP-4 and 5 spacecraft were processed and analyzed from launch through reentry. Approximately 95 percent of all data transmitted was recovered, processed, and analyzed. The computer programming and operational procedures which were developed to perform the processing and analysis of the data are discussed. The scientific results obtained from the analysis of the data are summarized. A bibliography of documents based on these experiments is included.
Simpson, J. A.↗
Imp F/G(4,5)
The development and characteristics of a solid state cosmic ray telescope for use on the IMP F and G missions are discussed. The charged particle telescopes are shown in cross section. The evolution of the telescope from previous instrument developments is described. The performance of the instruments during space missions is analyzed.
Simpson, J. A.↗
Summary of attitude dynamic analysis for IMP-J wire antenna spacecraft
The work is reported in the determination of acceptable deployment sequences, simulation of EFM antenna deployment, and contingency analysis for the IMP-J S/C. The spacecraft, mission profile and deployment sequences are described along with the simulation of EFM deployment and deployment failure.
Bell, L. W.↗
Intensity Oscillation of Low Energy Solar Particles Observed on the IMP 7 Satellite
Solar flare particles in the energy range from 125 to 160 KeV per charge were detected and analyzed by an electrostatic deflection vs. energy instrument on board the Explorer 47 (IMP 7) satellite. A harmonic analysis of the counting rates shows that frequently, the fluctuation of the particle flux can be approximately represented by N(t) = f(t)sin 2 pi nu t where f(t) is a smoothly varying function of t. The oscillation frequency nu varies from flare to flare and is of the order of 2 x .001/sec. The physical implications of the finding are discussed.
Fan, C. Y.↗
Observations of noise bands associated with the upper hybrid resonance by the Imp 6 radio astronomy experiment.
The intense noise bands occurring near the upper hybrid resonance frequency have been observed with the Imp 6 GSFC radio astronomy experiment in the plasmasphere. The identification of the upper hybrid resonance provides an accurate measure of the local electron density and allows the observed noise data to be fit to the scale of characteristic frequencies in the plasma. The data are consistent with earlier theoretical interpretations in which noise is generated between the upper hybrid and plasma frequencies and propagates to region 4 of the CMA diagram, where it is reflected at the L = 0 plasma cutoff.
Mosier, S. R.↗