IMP-6 (IMP-I or Explorer 43, NSSDC ID: 71-019A) was a 16-sided drum-shaped
spacecraft of dimensions: 1.8212 meter high and 1.3564 meter in diameter.
Its mass was 635 kg. The spacecraft spin axis was ... perpendicular to the
ecliptic plane with a spin rate of 5 rpm, giving it a spin period of
12 seconds. IMP-6 continued the study, begun by earlier IMPs, of the
interplanetary and outer magnetospheric regions by measuring energetic
particles, plasma, and electric and magnetic fields. A radio astronomy
experiment was also included in the spacecraft payload. The initial
apogee point was near the earth-sun line. The solar-cell and chemical-
battery powered spacecraft carried two transmitters. One continuously
transmitted PCM encoder data at a 1600-bps information bit rate. The
second transmitter was used for transmission of VLF data and for ranging
information. Three orthogonal pairs of dipole antennas were used for
the electric fields experiments, and one of these pairs was also used
for the radio astronomy experiment. The members of the antenna pair
along the spacecraft spin axis extended 2.9 meter, the members of the
antennal pair used in both the electric field and radio astronomy
experiments extended 45.5 meter, and the members of the third pair were
slightly unbalanced, extending 24.4 meter and 27.6 meter, respectively.
All four elements perpendicular to the spin axis were to have extended
45.5 meter. The spacecraft reentered the earth's atmosphere on October 2,
1974, after a highly successful mission. The IMP (Interplanetary
Monitoring Platform) spacecraft exploration program was carried out by
the United States.
Entry taken from:
Hills, H. K., R. G. Littlefield, N. J. Schofield and
J. I. Vette: 'Data Catalog Series for Space Science and
Applications Flight Missions', Vol. 3A, NSSDC/WDC-A,
NASA / Goddard Space Flight Center, September 1982.
Fairfield, D. H., Journal of Geophysical Research, 79, 1368, 1974.
Frank, L. A. et al., Journal of Geophysical Research,
82, 129, 1977.
Armstrong, T. and S. M. Krimigis, Journal of Geophysical
Research, 81, 677, 1976.
Williams, D. J., NOAA Technical Report, ERL 393-SEL 40,
U.S. Department of Commerce, Boulder, Colorado, USA,