SATELLITE DESCRIPTION:
The spacecraft was designed and configured the same as all previous
NIMBUS satellites. The total weight of the spacecraft was the
largest ever for a meteorological satellite-1366 pounds. The excess
weight of NIMBUS IV was due to a piggyback TOPO I experiment
designed to test transponders and antennas for space-ground
triangulation exercises for the US Army for ground tactical
positioning, and the addition of four new experiments to the seven
flown on NIMBUS III.
The new experiments included a backscatter ultraviolet
spectrometer, a filter wedge spectrometer, a selective chopper
radiometer, and a temperature, humidity and infrared radiometer.
The SIRS, HRIR and MRIR flown on NIMBUS III were removed from
NIMBUS IV to make room for the new experiments. The craft was
powered by 10,500 solar cells and two SNAP-19 nuclear powered
generators.