Weather Satellites: NIMBUS III

NIMBUS III

Launch date: April 13, 1969

Launch site: Vandenberg Air Force Base, California

Launch vehicle: Thorad-Agena D

PROGRAM OBJECTIVE:

NIMBUS III was a replacement for NIMBUS B which was destroyed in a launch failure. NIMBUS III was the first US weather satellite to make day and night global measurements from space of temperatures at varying levels in the atmosphere. Other mission objectives included providing support for international programs designed to gather vital oceanographic data, and large-scale atmospheric data for use in newly designed computer prediction models of the atmosphere.

SATELLITE DESCRIPTION:

The spacecraft was designed and configured the same as the NIMBUS I and II crafts. Seven new experiments were on board this craft (identical to those on the aborted NIMBUS B) making the total weight of the spacecraft the largest ever for a meteorological satellite-1269 pounds.

The craft contained an Infrared Interferometer Spectrometer (IRIS) to measure atmospheric temperature, water vapor, and ozone in the vertical. A Satellite Infrared Spectrophotometer (SIRS) was used to take similar temperature readings as the IRIS for comparison purposes. An Interrogation Recording and Location System (IRLS) was used to locate, identify and relay transmissions from data gathering buoys on the surface of the Earth. A Monitor of Ultraviolet Solar Energy (MUSE) was used to measure the amount of ultraviolet radiation reaching the atmosphere from the sun. The Image Dissector Camera (IDC) replaced the old vidicon cameras which had been used to provide APT to surface ground stations. A High Resolution and Medium Resolution Infrared radiometer (HRIR and MRIR) were used to provide infrared images at night as on the previous NIMBUS series satellites. 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 III remained operational until January 22, 1972.

PARTICIPANTS:

NASA, General Electric, ITT, ESSA, Woods Hole Oceanographic Institute, US Weather Bureau, USAF Air Weather Service, Bureau of Commercial Fisheries, Nuclear Regulatory Commission.