Wide Field Infrared Explorer

Infobox_Spacecraft
Name = Wide Field Infrared Explorer


Caption =
Organization = NASA
Major_Contractors =
Mission_Type = Surveyor
Flyby_Of =
Satellite_Of = Earth
Orbital_Insertion_Date =
Launch = 1999
Launch_Vehicle = Pegasus rocket
Decay =
Mission_Duration =
NSSDC_ID = 1999-011A
Webpage = [http://nssdc.gsfc.nasa.gov/database/MasterCatalog?sc=1999-011A]
Mass =
Power =
Orbital_elements =
Semimajor_Axis =
Eccentricity =
Inclination =
Orbital_Period =
Apoapsis =
Periapsis =
Orbits =

The Wide Field Infrared Explorer (WIRE) is a satellite launched in 1999 by a Pegasus rocket into a polar orbit between 409 km and 426 km above the Earth's surface. WIRE was intended to be a four-month infrared survey of the entire sky, specifically focusing on starburst galaxies and luminous protogalaxies. The science team was based at the Infrared Processing and Analysis Center in Pasadena, California. Flight operations, integration, and testing were from Goddard Space Flight Center in Maryland. The telescope and cryo-assembly were built by Space Dynamics Laboratories in Utah.

A design flaw in the spacecraft control electronics caused the telescope dust cover to eject prematurely in its first few hours on-orbit, exposing the telescope to the Earth. In normal operations the telescope would avoid pointing at the Earth as well as the Sun because the heat load was too high for the cryogenic cooling. At this early stage in the mission, the telescope was deliberately pointed at the Earth for safety reasons under the assumption that the dust cover was present. The influx of power into the telescope caused the solid hydrogen cryostat to boil off all of its cryogen. As a result, the cryostat vent, now expelling gas at rates orders of magnitude higher than designed, acted as a tiny thruster rocket overwhelming the attitude control system and ultimately spinning the spacecraft up as high as 60 rpm. After the hydrogen was exhausted, spacecraft engineers were able to re-establish attitude control. However, with the cryogen gone, the science instrument was no longer functional and the science mission ended.

Spacecraft operations have been redirected to use the onboard star tracker for long-term monitoring of bright stars in support of an asteroseismology program. This technique aims to measure oscillations in nearby stars to probe their structure. The star tracker has poor spatial resolution, having been designed primarily for a wide field of view and detection of the brightest stars. However, it is above the atmosphere and thus avoids scintillation, enabling high-precision photometry.

See the WIRE Home Page [http://www.ipac.caltech.edu/wire/] at IPAC for more information.

External links

* cite web
url = ftp://ftp.hq.nasa.gov/pub/pao/reports/1999/wire_summary.pdf
title = WIRE Mishap Investigation Board Report
format = PDF
publisher = NASA
accessmonthday = June 8
accessyear = 1999