Nimbus 5

Nimbus 5 (also called Nimbus E or Nimbus V) was a meteorological satellite for the research and development of sensing technology. It was the fifth successful launch in a series of the Nimbus program.

Nimbus 5

Mission type	Weather satellite
COSPAR ID	1972-097A
SATCAT no.	06305
Spacecraft properties
Manufacturer	RCA Astrospace
Launch mass	770.0 kg (1,697.6 lb)
Dimensions	3.7 metres (12 ft) tall x 1.5 metres (4 ft 11 in) dia.
Start of mission
Launch date	December 11, 1972 07:56:00 (1972-12-11UTC07:56Z) UTC[1]
Rocket	Delta-900 577/D93
Launch site	Vandenberg SLC-2W
End of mission
Last contact	March 29, 1983 (1983-03-30)[2]
Orbital parameters
Reference system	Geocentric
Regime	Low Earth
Eccentricity	0.0008
Perigee altitude	1,089 kilometers (677 mi)
Apogee altitude	1,101 kilometers (684 mi)
Inclination	99°
Period	107.2 minutes
Nimbus program ← Nimbus 4 Nimbus 6 →

The objective of Nimbus 5 was to test and evaluate advanced sensing technology, and to provide improved photographs of cloud formations.^[3]

Launch

Nimbus 5 was launched on December 11, 1972, by a Delta rocket from Vandenberg Air Force Base in California. The satellite orbited the Earth once every 107 minutes, at an inclination of 99°. Its perigee was 1,089 kilometers (677 mi) and its apogee was 1,101 kilometers (684 mi).

Instruments

There were six science instruments aboard Nimbus 5. The satellite also included Sun sensors, and horizon scanners for navigation.

Infrared Temperature Profile Radiometer (ITPR)

The ITPR was designed to obtain vertical profiles of temperature and moisture in the atmosphere. A 3-dimensional map could then be created with a resolution of 32 km.^[4]

Selective Chopper Radiometer (SCR)

The SCR had three objectives: to observe the global atmospheric temperature structure, to observe the distribution of water vapor, and to measure the density of ice crystals in cirrus clouds. Its sensing resolution was about 25 km.^[5]

Electrically Scanning Microwave Radiometer (ESMR)

Main article: Electrically scanning microwave radiometer

ESMR was used for mapping the microwave radiation from Earth's surface. This information was used to measure the water content of clouds, and to observe sea ice. It was also used to test the use of microwaves to measure soil moisture. The antenna system was deployed after launch, and controlled by an onboard computer.^[7]

Surface Composition Mapping Radiometer (SCMR)

For measuring the thermal emission characteristics of Earth's surface and sea temperatures. A scanning mirror rotated ten times per second to sense sections 800 km wide. SCMR malfunctioned soon after launch.^[8]