NASM Space Artifacts: IRAS Infrared Astronomical Satellite (IRAS) Source: Space History Source: Space History Infrared Astronomical Satellite (IRAS) Full Scale Replica The Infrared Astronomical Satellite was a joint venture between NASA and its counterparts in the Netherlands and Great Britain. In the U.S. the Ball Corporation's Aerospace Systems Division served as the prime contractor for the telescope system and was responsible for many of the aspects of the structural, thermal and flight units. The satellite was launched on January 25, 1983 from Vandenberg Air Force Base on a Delta rocket. The payload was inserted into a near-circular orbit at about 900 km. IRAS produced infrared maps of the sky at 12, 25, 60 and 100 microns during 10 months of operation before its liquid helium was exhausted. The artifact is a full-scale replica constructed by Ball, with assistance from the Jet Propulsion Laboratory, Perkin-Elmer and the Netherlands Aerospace Agency. Reconstruction began in mid-1986 using backup and leftover parts, with some new components. This replica was displayed in several local displays in Colorado prior to shipping to NASM. IRAS was donated to the Museum by the Ball Corporation in April 1987 and was on display in the Stars Gallery from that time until October 1997. Dimensions: D: 172 cm (77 inches) L: 358 cm (142 inches) W: 324 cm (118 inches) with solar panels. Description: Roughly cylindrical satellite with a large asymmetrical sunshield and a single flat solar panel supported on struts. The fore and aft sections of the body of the satellite are covered with metallized (aluminum and gold) insulating blanketing, and the center of the body is painted white. The replica includes an optical telescope assembly with high-definition secondary support structures and baffling. Composition of the materials in the replica not completely known but includes aluminum, magnesium and composite materials. History: Ground based surveys of the sky carried out in the 1960s and 1970s pointed to the existence of many sources of infrared radiation in the cosmos. The presence of substances like water vapor in the Earth's atmosphere, which absorb in the infrared range, constrained data acquisition to relatively small windows in the infrared spectrum. These sky surveys however, created a constituency that pushed for a large infrared telescope in space, and led to the Infrared Astronomical Satellite (IRAS). IRAS was an international joint project involving NASA centers such as the Jet Propulsion Laboratory and the Ames Research Center in the United States, the Netherlands Space Agency and the Science and Engineering Research Council in the United Kingdom. To view the infrared sky, any detector has to be cooler than the object it wants to detect. Therefore infrared detectors need to be cooled not only to increase their sensitivity but to render the objects they seek visible; in the case of IRAS, the entire optical instrument was cooled as well to cut down instrument noise. The entire telescope was placed inside a Dewar-like container filled with 70 kg of pressurized liquid helium keeping the whole assembly at 2 Kelvins (2 degrees above absolute zero). A specially designed sintered metal plug controlled the slow evaporation of helium. The helium supply allowed the instrument to collect useful data for about 300 days. The 62 solid state focal plane detectors provided sensitivity to wavelength bands at 12, 25 60 and 100 microns. Additional instrumentation included two photometers and a low-resolution spectrometer used to obtain spectra of strong point sources over the 7.4 to 23 micron range. The satellite was launched from Vandenberg Air Force Base on January 25, 1983 on a Delta rocket and inserted into a polar orbit designed to minimize accidental exposure to bright sources such as the sun or earth. Observational data were collected by two on-board tape recorders with a combined capacity of 0.9 megabytes. Once each day, data were downloaded to a receiving station in Chilton, England and were then transmitted via communications satellite to the Jet Propulsion Laboratory in California for computer analysis. The infrared map of the celestial sphere produced from IRAS data led to the discovery of more than 250,000 new sources of infrared radiation; this included over 10,000 new galaxies. IRAS provided new data that helped revise theories of star formation since infrared radiation penetrates the gas and dust that hides the process from visual inspection. IRAS led to the discovery of numerous new objects including the first comet, IRAS-Araki-Alcock, to be detected by a satellite, and a new type of quasar that emits more than 90% of its energy as infrared radiation. Data from IRAS provided material for the publication of close to 500 scientific papers and two massive review articles by 1987. References "IRAS," Ball Line Magazine, 1987, Number 2. Soifer, B. T., Houck, J. R., Neugebauer, G., "The IRAS View of the Extragalactic Sky," Ann. Rev. Astron. Astrophys. 25:187-230 (1987). Beichman, C. A., "The IRAS View of the Galaxy and the Solar System," , Ann. Rev. Astron. Astrophys. 25:521-563 (1987). Beichman, C. A., Neugebauer, G., Habing, H. J., Clegg, E., Chester, T. J., eds, IRAS Catalogue and Atlases: Explanatory Supplement. GPO, 1988. "IRAS, Mapping the Infrared Sky," 1997, NASA Facts, NF-139, http://tommy.jsc.nasa.gov/~woodfill/SPACEED/SEHHTML/infra.html DL/DHD 10/1997 Civilian Space ApplicationsGuidance, Navigation, and ControlHumans in SpaceInternational SpaceMilitary SpaceRockets and MissilesSpace ScienceNASM Home Page This page updated: 08/18/99 Author: Space History Division E-mail Inquiries ©1995-2000 Smithsonian, National Air and Space Museum Copyright Information