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Other Designations: Wide Field Infrared Explorer. Class: Astronomy. Type: Infrared. Destination: Sun Synchronous Orbit. Nation: USA. Agency: NASA, JPL. Manufacturer: NASA Greenbelt. WIRE was designed to survey the celestial sky in the infrared bands and build on the results of the IRAS mission. WIRE was one of two missions selected in 1994 as part of NASA's Small Explorer Program (SMEX). The specific objectives of the WIRE mission were to: (1) determine what fraction of the luminosity of the universe at a red shift of 0.5 and beyond was due to starburst galaxies; (2) determine whether luminous protogalaxies were common at red shifts less than 3; (3) amass a catalogue larger than the IRAS Point Source Catalogue; and (4) make a survey more than 500 times fainter than the IRAS Faint Source Survey at 12 and 25 µm. The spacecraft used the Small Explorer bus. It was 3-axis stabilized, using a momentum biased control system with 2 arc-minutes pointing. This used reaction wheels, gyros, a star tracker, torque rods, and sun-sensors. The non-articulated solar array provided 170 W orbit average power using GaAs cells and recharged one 9 AHr Super NiCd battery. The control system used an 80386 processor with 88 MBytes memory. Uplink was at 2 kbps, downlink at 18.75, 900, and 1800 kbps using a 5 W S-Band transponder. Payload was a 30 cm aperture Cassegrain telescope, diffraction limited at 25 µ m, with no moving parts or reimaging optics, feeding two 128 x 128 Si: As BIB focal plane arrays. Optics were cooled to less than 19 Kelvin and detectors were cooled to less than 7.5 Kelvin using 3 kg of solid hydrogen. Instrument power was 35 watts, with an average data rate of 9 kbps. Each exposure lasted 32 - 128 seconds. The contract for 2 units + options was issued on 17 April 1995. Design Life: 4 months. Typical orbit: 400 km, circular, polar, sun-synchronous. WIRE Chronology
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