IRAS

Infra Red Astronomy Satellite

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General

Designation	13777 / 83004A
Launch date	26 Jan 1983
Country of origin	Netherlands, United Kingdom and United States
Mission	Scientific: IR astronomy
Perigee/Apogee	884/903 km
Inclination	99°
Period	102.9 min
Launch vehicle	Thor Delta #166

It mapped 250,000 IR sources in the 300 days before its helium coolant was exhausted.

On 29 Jan 2020 IRAS had a near miss with Poppy 5B, less than 100 meters appart.

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End of life

Out of service

23 Nov 1983

Technical data

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Specifications

Industrial responsabilities	Netherlands Aerospace Agency (bus) NASA Ames Research Center, JPL (telescope) SERC (TT&C and data collection) Prime contractors: ICIRAS (bus) Ball Aerospace (telescope) Perkin-Elmer (optics)
Mass at launch	1077 kg
Telescope mass	810 kg
Diameter	2.2 m
Height	3.6 m
Solar array	5 m² (2 panels)
Stabilization	3-axis
DC power	EOL: 500 W
Design lifetime	11 months

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Payload

Ritchey-Chretien-type reflecting telescope with a local plane array of 62 IR detectors surrounded by a dewar containing 475 l of liquid helium. Plus 2 photometers and a low-resolution spectrometer.

Telescope diameter	0.57 m
Focal length	5.5 m
Field of view	30 arcmin

Spectral range:

IR Telescope	(band 1) 8.5-15 µm (band 2) 19-30 µm (band 3) 40-80 µm (band 4) 83-119 µm
Spectrometer	7.4-23 µm
Short wavelength photometer	4.1-8 µm

Cooling system by evaporated helium

Temperature control	2 K
Telemetry/data	S-band (1 Mbps)

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