The Infrared Astronomical Satellite (
Dutch: ''Infrarood Astronomische Satelliet'') (IRAS) was the first
space telescope to perform a
survey
Survey may refer to:
Statistics and human research
* Statistical survey, a method for collecting quantitative information about items in a population
* Survey (human research), including opinion polls
Spatial measurement
* Surveying, the techniq ...
of the entire
night sky
The night sky is the nighttime appearance of celestial objects like stars, planets, and the Moon, which are visible in a clear sky between sunset and sunrise, when the Sun is below the horizon.
Natural light sources in a night sky include ...
at
infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
wavelength
In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats.
It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, tro ...
s. Launched on 25 January 1983,
its mission lasted ten months.
The telescope was a joint project of the United States (
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research.
NASA was established in 1958, succeeding t ...
), the Netherlands (
NIVR), and the United Kingdom (
SERC). Over 250,000 infrared sources were observed at 12, 25, 60, and 100 micrometer wavelengths.
Support for the processing and analysis of data from IRAS was contributed from the
Infrared Processing and Analysis Center at the
California Institute of Technology. Currently, the
Infrared Science Archive at IPAC holds the IRAS archive.
The success of IRAS led to interest in the 1985
Infrared Telescope
An infrared telescope is a telescope that uses infrared light to detect celestial bodies. Infrared light is one of several types of radiation present in the electromagnetic spectrum.
All celestial objects with a temperature above absolute zero ...
(IRT) mission on the Space Shuttle, and the planned Shuttle Infrared Telescope Facility which eventually transformed into the Space Infrared Telescope Facility, SIRTF, which in turn was developed into the
Spitzer Space Telescope
The Spitzer Space Telescope, formerly the Space Infrared Telescope Facility (SIRTF), was an infrared space telescope launched in 2003. Operations ended on 30 January 2020. Spitzer was the third space telescope dedicated to infrared astronomy, f ...
, launched in 2003. The success of early infrared space astronomy led to further missions, such as the
Infrared Space Observatory
The Infrared Space Observatory (ISO) was a space telescope for infrared light designed and operated by the European Space Agency (ESA), in cooperation with ISAS (now part of JAXA) and NASA. The ISO was designed to study infrared light at wavelengt ...
(1990s) and the
Hubble Space Telescope
The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most versa ...
NICMOS
The Near Infrared Camera and Multi-Object Spectrometer (NICMOS) is a scientific instrument for infrared astronomy, installed on the Hubble Space Telescope (HST), operating from 1997 to 1999, and from 2002 to 2008. Images produced by NICMOS contain ...
instrument.
Mission
IRAS was the first observatory to perform an all-sky survey at infrared wavelengths. It mapped 96% of the sky four times, at 12, 25, 60 and 100 micrometers, with resolutions ranging from 30 arcseconds at 12 micrometers to 2 arcminutes at 100 micrometers. It discovered about 350,000 sources, many of which are still awaiting identification. About 75,000 of those are believed to be
starburst galaxies, still enduring their
star-formation stage. Many other sources are normal stars with disks of dust around them, possibly the early stage of
planetary system
A planetary system is a set of gravitationally
In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interacti ...
formation. New discoveries included a dust disk around
Vega
Vega is the brightest star in the northern constellation of Lyra. It has the Bayer designation α Lyrae, which is Latinised to Alpha Lyrae and abbreviated Alpha Lyr or α Lyr. This star is relatively close at only from the Sun, an ...
and the first images of the
Milky Way
The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye ...
core.
IRAS's life, like that of most infrared satellites that followed, was limited by its cooling system. To effectively work in the infrared domain, a telescope must be cooled to cryogenic temperatures. In IRAS's case, of
superfluid helium
Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. ...
kept the telescope at a temperature of , keeping the satellite cool by
evaporation
Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when humidi ...
. IRAS was the first use of superfluids in space. The on-board supply of liquid helium was depleted after 10 months on 21 November 1983, causing the telescope temperature to rise, preventing further observations. The spacecraft continues to orbit the Earth.
IRAS was designed to catalog fixed sources, so it scanned the same region of sky several times. Jack Meadows led a team at Leicester University, including
John K. Davies and
Simon F. Green, which searched the rejected sources for moving objects. This led to the discovery of three
asteroid
An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere.
...
s, including
3200 Phaethon
3200 Phaethon (previously sometimes spelled Phaeton), provisional designation , is an active Apollo asteroid with an orbit that brings it closer to the Sun than any other named asteroid (though there are numerous unnamed asteroids with smaller ...
(an
Apollo asteroid and the parent body of the
Geminid
The Geminids are a prolific meteor shower caused by the object 3200 Phaethon, which is thought to be a Palladian asteroid with a " rock comet" orbit. This would make the Geminids, together with the Quadrantids, the only major meteor showers ...
meteor shower
A meteor shower is a celestial event in which a number of meteors are observed to radiate, or originate, from one point in the night sky. These meteors are caused by streams of cosmic debris called meteoroids entering Earth's atmosphere at extre ...
), six
comet
A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ar ...
s, and a huge dust trail associated with comet
10P/Tempel. The comets included
126P/IRAS,
161P/Hartley–IRAS, and
comet IRAS–Araki–Alcock (C/1983 H1), which made a close approach to the Earth in 1983. Out of the six comets IRAS found, four were long period and two were short period comets.
Discoveries
![IRAS in orbit](https://upload.wikimedia.org/wikipedia/commons/8/8b/IRAS_in_orbit.jpg)
Overall, over a quarter million discrete targets were observed during its operations, both inside and beyond the
Solar System
The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar S ...
.
In addition, new objects were discovered including asteroids and comets.
The observatory made headlines briefly with the announcement on 10 December 1983 of the discovery of an "unknown object" at first described as "possibly as large as the giant planet
Jupiter
Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but ...
and possibly so close to
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
that it would be part of this solar system". Further analysis revealed that, of several unidentified objects, nine were distant galaxies and the tenth was "
intergalactic cirrus".
None were found to be Solar System bodies.
During its mission, IRAS (and later the Spitzer Space Telescope) detected odd infrared signatures around several stars. This led to the systems being targeted by the Hubble Space Telescope's NICMOS instrument between 1999 and 2006, but nothing was detected. In 2014, using new image processing techniques on the Hubble data, researchers discovered
planetary disks around these stars.
IRAS discovered six comets, out of total of 22 discoveries and recoveries of all comets that year.
This was a lot for this period, before the launch of
SOHO
Soho is an area of the City of Westminster, part of the West End of London. Originally a fashionable district for the aristocracy, it has been one of the main entertainment districts in the capital since the 19th century.
The area was develop ...
in 1995, which would allow the discovery of many more comets in the next decade (it would detect 1000 comets in ten years).
Asteroid discoveries
Later surveys
Several infrared space telescopes have continued and greatly expanded the study of the infrared Universe, such as the
Infrared Space Observatory
The Infrared Space Observatory (ISO) was a space telescope for infrared light designed and operated by the European Space Agency (ESA), in cooperation with ISAS (now part of JAXA) and NASA. The ISO was designed to study infrared light at wavelengt ...
launched in 1995, the
Spitzer Space Telescope
The Spitzer Space Telescope, formerly the Space Infrared Telescope Facility (SIRTF), was an infrared space telescope launched in 2003. Operations ended on 30 January 2020. Spitzer was the third space telescope dedicated to infrared astronomy, f ...
launched in 2003, and the
Akari Space Telescope launched in 2006.
A next generation of infrared space telescopes began when NASA's
Wide-field Infrared Survey Explorer
Wide-field Infrared Survey Explorer (WISE, observatory code C51, Explorer 92 and SMEX-6) is a NASA infrared astronomy space telescope in the Explorers Program. It was launched in December 2009, and placed in hibernation mode in February 2011, ...
launched on 14 December 2009 aboard a
Delta II
Delta II was an expendable launch system, originally designed and built by McDonnell Douglas. Delta II was part of the Delta rocket family and entered service in 1989. Delta II vehicles included the Delta 6000, and the two later Delta 7000 va ...
rocket from
Vandenberg Air Force Base. Known as WISE, the telescope provided results hundreds of times more sensitive than IRAS at the shorter wavelengths; it also had an extended mission dubbed
NEOWISE beginning in October 2010 after its coolant supply ran out.
A planned mission is NASA's
Near-Earth Object Surveillance Mission (NEOSM), which is a successor to the NEOWISE mission.
2020 near-miss
On , IRAS was expected to pass as closely as 12 meters from the U.S. Air Force's Gravity Gradient Stabilization Experiment (
GGSE-4 The Gravity Gradient Stabilization Experiment (GGSE-4) was a technology satellite launched in 1967. This was ostensibly the GGSE-1, fourth in a series that developed designs and deployment techniques later applied to the NOSS/Whitecloud reconnaissa ...
) of 1967, another un-deorbited satellite left aloft; the 14.7-kilometer per second pass had an estimated risk of collision of 5%. Further complications arose from the fact that GGSE-4 was outfitted with an 18 meter long stabilization boom that was in an unknown orientation and may have struck the satellite even if the spacecraft's main body did not. Initial observations from amateur astronomers seemed to indicate that both satellites had survived the pass, with the California-based debris tracking organization LeoLabs later confirming that they had detected no new tracked debris following the incident.
See also
*
GGSE-4 The Gravity Gradient Stabilization Experiment (GGSE-4) was a technology satellite launched in 1967. This was ostensibly the GGSE-1, fourth in a series that developed designs and deployment techniques later applied to the NOSS/Whitecloud reconnaissa ...
*
Diffuse Infrared Background Experiment
Diffuse Infrared Background Experiment (DIRBE) was an experiment on NASA's COBE mission, to survey the diffuse infrared sky. Measurements were made with a reflecting telescope with 19 cm diameter aperture.Riccardo Giacconi, Daniela Calzetti, ...
, an infrared sky survey on
COBE (1989)
*
Infrared astronomy
Infrared astronomy is a sub-discipline of astronomy which specializes in the observation and analysis of astronomical objects using infrared (IR) radiation. The wavelength of infrared light ranges from 0.75 to 300 micrometers, and falls in betwee ...
*
List of asteroid-discovering observatories
The list of asteroid-discovering observatories contains a section for each observatory which has discovered one or more asteroids, along with a list of those asteroids.
For each numbered asteroid, the Minor Planet Center lists one or more discov ...
*
List of largest infrared telescopes
The largest infrared telescopes for infrared astronomy are listed in terms of diameter of primary mirror. The infrared spectrum with its longer wavelength than visible light has a number of challenges, especially for ground-based observatories ...
*
*
:IRAS catalogue objects
References
Bibliography
*
External links
IRAS websiteby Caltech
by the Planetary Science Institute
IRAS surveyat WikiSky.org
{{Authority control
Asteroid surveys
Astronomical surveys
*
Minor-planet discovering observatories
Infrared telescopes
Space telescopes
Spacecraft launched in 1983
Satellites of the Netherlands