This page no longer updated from 31 October 2001. Latest version can be found at www.astronautix.com

astronautix.com WIRE


Other Designations: Wide Field Infrared Explorer. Class: Astronomy. Type: Infrared. Nation: United States. Agency: NASA, JPL. Manufacturer: NASA Goddard Space Flight Center.

WIRE was one of two missions selected in 1994 as part of NASA's Small Explorer Program (SMEX). The spacecraft will survey the celestial sky in the infrared bands and will build on the results of the IRAS mission. The specific objectives of the WIRE mission are to: (1) determine what fraction of the luminosity of the universe at a redshift of 0.5 and beyond is due to starburst galaxies; (2) determine whether luminous protogalaxies are common at redshifts 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 m. Spacecraft: Small Explorer bus.3-axis stabilised, momentum biased control system with 2 arc-minutes pointing. Uses reaction wheels, gyros, star tracker, torque rods, sun-sensors. Non-articulated solar array provides 170 W orbit average power using GaAs cells. One 9 AHr Super NiCd battery.80386 processor with 88 MBytes memory. Uplink at 2 kbps, downlink at 18.75, 900, and 1800 kbps using 5 W S-Band transponder. Payload: A 30 cm aperture Cassegrain telescope, diffraction limited at 25 m, with no moving parts or reimaging optics. Two 128 x 128 Si: As BIB focal plane arrays. Optics are cooled to less than 19 Kelvin and detectors are cooled to less than 7.5 Kelvin using 3 kg solid hydrogen. Instrument power is 35 watts, with average data rate of 9 kbps. Each exposure lasts 32 - 128 seconds.
Financial/Operational:
Contract for 2 units + option on April 17 1995.


Specification

Design Life: 4 months.


WIRE Chronology


17 April 1995 WIRE contract issued
05 March 1999 WIRE Launch Site: Vandenberg . Launch Vehicle: Pegasus XL. Perigee: 537 km. Apogee: 582 km. Inclination: 97.5 deg.

NASA's long-delayed WIRE (Wide Field Infrared Explorer) astronomy satellite was the fifth Small Explorer (SMEX) mission managed by NASA-Goddard. The L-1011 Stargazer launch aircraft took off from Vandenberg's runway 30/12 at 01:55 GMT on March 2 for the first launch attempt. The planned 02:56 GMT launch was cancelled at T-46 seconds due to a problem with the tail fin release mechanism of the Pegasus XL launch vehicle. The second attempt was successful, with the Pegaus XL being dropped at 36 degrees N x 123 degrees W over the Pacific Ocean at 02:56 GMT. However the WIRE ran into serious trouble shortly after orbit injection. The cover of the solid hydrogen telescope ejected prematurely, and the cryogenic coolant evaporated and vented, spinning the satellite out of control. WIRE was going to make an infrared photometry survey, generating a large catalog of galaxies and quasars.



Bibliography:



Back to Index
Last update 12 March 2001.
Contact Mark Wade with any corrections or comments.
Conditions for use of drawings, pictures, or other materials from this site..
© Mark Wade, 2001 .