Weather Satellites: NIMBUS IV

NIMBUS IV

Launch date: April 8, 1970

Launch site: Vandenberg Air Force Base, California

Launch vehicle: Thorad-Agena D

PROGRAM OBJECTIVE:

Continuation of research, development and testing of new meteorological sensors, systems and systems configurations to measure atmospheric temperature, water vapor and ozone. Those sensors which could be used in operational weather analysis and prediction were to be added to the TIROS/ESSA operational weather satellite program.

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.

The craft was placed in sun synchronous orbit and transmission of data from all of the experiments was completed as scheduled. NIMBUS IV remained operational over 10 years until it was deactivated on September 30, 1980.

PARTICIPANTS:

NASA, General Electric, ESSA, US Weather Bureau, USAF Air Weather Service, Oxford University, University of Wisconsin, University of Maryland.