View source for IRAS

{{Short description|Infrared space observatory}}
{{About|the space telescope||IRAS (disambiguation)}}
{{Infobox spaceflight |auto=all
| name                  = Infrared Astronomical Satellite / Infrarood Astronomische Satelliet
| image                 = File:IRAS testing.jpg
| image_caption         = Infrared Astronomical Satellite in space simulator at JPL, 1982
| image_size            =

| mission_type          = Infrared [[space observatory]]
| operator              = {{plainlist|
*[[NASA]]
*[[Netherlands Agency for Aerospace Programmes|NIVR]]
*[[Science and Engineering Research Council|SERC]]
}}
| COSPAR_ID             = 1983-004A
| SATCAT                = 13777
| website               = {{URL|http://irsa.ipac.caltech.edu/Missions/iras.html}}
| mission_duration      = Final: {{time interval|25 January 1983 21:17|21 November 1983|show=ymd|sep=,}}

| manufacturer          = {{plainlist|
*[[Ball Aerospace & Technologies|Ball Aerospace]]
*[[Fokker#Aerospace|Fokker Space]]
*[[Thales Nederland|Hollandse Signaal]]
}}
| launch_mass           = {{convert|1083|kg|lb|abbr=on}}
| dry_mass              = 
| dimensions            = {{convert|3.60|xx|3.24|xx|2.05|m|ft|abbr=on}}{{sfn|Beichman|1988|p=II-1}}
| power                 = <!--end-of-life power, in watts-->

| launch_date           = {{start-date|25 January 1983, 21:17}}&nbsp;[[UTC]]<ref name="iras-mission">{{cite web |url=http://www.jpl.nasa.gov/missions/infrared-astronomical-satellite-iras/ |title=Infrared Astronomical Satellite |publisher=[[NASA]] |access-date=19 November 2016}}</ref>
| launch_rocket         = [[Delta 3000|Delta 3910]]
| launch_site           = [[Vandenberg Air Force Base|Vandenberg]] [[Vandenberg AFB Space Launch Complex 2|SLC-2W]]
| entered_service       = 9 February 1983<ref name="Neugebauer1984">{{cite journal |title=The Infrared Astronomical Satellite (IRAS) mission |journal=Astrophysical Journal |first1=G. |last1=Neugebauer |first2=H. J. |last2=Habing |first3=R. |last3=van Duinen |first4=H. H. |last4=Aumann |first5=B. |last5=Baud |display-authors=etal |volume=278 |pages=L1–L6 |date=March 1984 |doi=10.1086/184209 |bibcode=1984ApJ...278L...1N|hdl=1887/6453 |url=https://openaccess.leidenuniv.nl/bitstream/handle/1887/6453/ApJ_278_L1_L6.pdf?sequence=1 |hdl-access=free }}</ref>

| disposal_type         = Decommissioned
| deactivated           = {{end-date|21 November 1983}}<ref name="iras-mission" />
| decay_date            = <!--when craft re-entered the atmosphere, not needed if it landed-->

| orbit_reference       = [[Geocentric orbit|Geocentric]]
| orbit_regime          = [[Sun-synchronous orbit|Sun-synchronous]]
| orbit_semimajor       = {{convert|7270.69|km|mi|abbr=on}}
| orbit_eccentricity    = 0.001857
| orbit_periapsis       = {{convert|879.05|km|mi|abbr=on}}
| orbit_apoapsis        = {{convert|906.05|km|mi|abbr=on}}
| orbit_inclination     = 98.95 deg
| orbit_period          = 102.8 min
| orbit_mean_motion     = 14.00 rev/day
| orbit_epoch           = 19 November 2016, 04:15:30&nbsp;[[UTC]]<ref name="heavens-above">{{cite web |url=http://heavens-above.com/orbit.aspx?satid=13777 |title=IRAS - Orbit |work=[[Heavens-Above]] |date=19 November 2016 |access-date=19 November 2016}}</ref>
| apsis                 = gee

| telescope_type        = [[Ritchey–Chrétien telescope|Ritchey–Chrétien]]{{sfn|Beichman|1988|p=II-8}}
| telescope_diameter    = {{convert|57|cm|in|abbr=on}}{{sfn|Beichman|1988|p=II-8}}
| telescope_focal_length= {{convert|545|cm|in|abbr=on}}, {{f/|9.56}}{{sfn|Beichman|1988|p=II-8}}
| telescope_area        = {{convert|2019|cm2|sqin|abbr=on}}{{sfn|Beichman|1988|p=II-8}}
| telescope_wavelength  = Long-wavelength to far-[[infrared]]
| instruments_list      = {{Infobox spaceflight/Instruments
  | acronym1 = SA  | name1 = Survey Array
  | acronym2 = LRS | name2 = Low Resolution Spectrometer
  | acronym3 = CPC | name3 = Chopped Photometric Channel
 }}
}}

The '''Infrared Astronomical Satellite''' ([[Dutch language|Dutch]]: ''Infrarood Astronomische Satelliet'') ('''IRAS''') was the first [[space telescope]] to perform a [[astronomical survey|survey]] of the entire [[night sky]] at [[infrared]] [[wavelength]]s.{{sfn|Beichman|1988|p=I-1}} Launched on 25 January 1983,<ref name="iras-mission" /> its mission lasted ten months.<ref name="springer" /> The telescope was a joint project of the United States ([[NASA]]), the Netherlands ([[Netherlands Agency for Aerospace Programmes|NIVR]]), and the United Kingdom ([[Science and Engineering Research Council|SERC]]). Over 250,000 infrared sources were observed at 12, 25, 60, and 100&nbsp;micrometer wavelengths.<ref name="springer" />

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.<ref>{{cite web |url=http://www.ipac.caltech.edu/project/15 |title=Infrared Astronomical Satellite |work=Infrared Processing and Analysis Center |publisher=[[Caltech]] |access-date=19 November 2016 |archive-date=6 June 2016 |archive-url=https://web.archive.org/web/20160606065714/http://www.ipac.caltech.edu/project/15 |url-status=dead }}</ref><ref>{{cite web |url=http://irsa.ipac.caltech.edu/Missions/iras.html |title=Infrared Astronomical Satellite (IRAS) |work=NASA/IPAC Infrared Science Archive |publisher=Caltech |access-date=19 November 2016}}</ref>

The success of IRAS led to interest in the 1985 [[STS-51-F|Infrared Telescope]] (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]], launched in 2003.<ref>{{cite web |url=http://www.spitzer.caltech.edu/info/66-Early-History |title=Early History |series=Spitzer Space Telescope |publisher=NASA |access-date=30 November 2016 |archive-date=2 August 2020 |archive-url=https://web.archive.org/web/20200802010257/http://www.spitzer.caltech.edu/info/66-Early-History |url-status=dead }}</ref> The success of early infrared space astronomy led to further missions, such as the [[Infrared Space Observatory]] (1990s) and the [[Hubble Space Telescope]]{{'s}} [[Near Infrared Camera and Multi-Object Spectrometer|NICMOS]] instrument.

== Mission ==
{{multiple image |align=left |direction=vertical |width=200
 |image1  = IRAS launch USAF-1369th audiovisual squadron-(MAC).jpg
 |caption1= Launch of IRAS in 1983
 |image2  = Comet IRAS-Araki-Alckock-1983.jpg
 |caption2= False color image of [[comet IRAS–Araki–Alcock]] by IRAS
 |image3  = IRAS all-sky infrared survey.jpg
 |caption3= Infrared all-sky survey by IRAS
}}

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&nbsp;micrometers, with resolutions ranging from 30&nbsp;arcseconds at 12&nbsp;micrometers to 2&nbsp;arcminutes at 100&nbsp;micrometers. It discovered about 350,000 sources, many of which are still awaiting identification.  About 75,000 of those are believed to be [[starburst galaxy|starburst galaxies]], still enduring their [[star formation|star-formation]] stage.  Many other sources are normal stars with disks of dust around them, possibly the early stage of [[planetary system]] formation.  New discoveries included a dust disk around [[Vega]] and the first images of the [[Milky Way]]{{'s}} 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, {{convert|73|kg|lb|sp=us}} of [[superfluid]] [[helium]] kept the telescope at a temperature of {{convert|2|K|C F|sigfig=3|lk=on}}, keeping the satellite cool by [[evaporation]]. IRAS was the first use of superfluids in space.<ref>{{cite book
 | last = Rowan-Robinson
 | first = Michael
 | author-link = Michael Rowan-Robinson
 | title = Ripples in the Cosmos
 | publisher = W. H. Freeman and Company
 | date = 1993
 | pages = 75
 | isbn = 0-7167-4503-8}}</ref> 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 (astronomer)|John K. Davies]] and [[Simon F. Green]], which searched the rejected sources for moving objects. This led to the discovery of three [[asteroid]]s, including [[3200 Phaethon]] (an [[Apollo asteroid]] and the parent body of the [[Geminids|Geminid]] [[meteor shower]]), six [[comet]]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.<ref name="springer" />

The Supplemental IRAS Minor Planet Survey (SIMPS) would also later use the archived data to search for more [[minor planet]]s, asteroids.<ref name="SIMPS"> {{cite web
|url= http://www.psi.edu/pds/resource/imps.html
|author= Tedesco
|display-authors= etal
|title= Supplemental IRAS Minor Planet Survey (SIMPS)
|access-date= 29 December 2008
|work= IRAS-A-FPA-3-RDR-IMPS-V6.0
|publisher= [[Planetary Data System]]
|date= 2004
|archive-url= https://web.archive.org/web/20090817051318/http://www.psi.edu/pds/resource/imps.html
|archive-date= 17 August 2009
}} </ref>

== Discoveries ==
[[File:IRAS in orbit.jpg|thumb|IRAS made its observations from Earth orbit in 1983]]
Overall, over a quarter million discrete targets were observed during its operations, both inside and beyond the [[Solar System]].<ref name="springer" /> In addition, new objects were discovered including asteroids and comets.<ref name="springer" />
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]] and possibly so close to [[Earth]] that it would be part of this solar system".<ref>{{cite news |url=http://web.ipac.caltech.edu/staff/tchester/iras/washington_post_mystery_object.html |title=Mystery Heavenly Body Discovered |newspaper=[[The Washington Post]] |first=Thomas |last=O'Toole |page=A1 |date=30 December 1983 |archive-url=https://web.archive.org/web/20100201211608/http://web.ipac.caltech.edu/staff/tchester/iras/washington_post_mystery_object.html |archive-date=1 February 2010}}</ref><ref>{{cite news |url=https://news.google.com/newspapers?id=Za80AAAAIBAJ&pg=6060,3461403 |title=Mystery heavenly body found close to Earth |work=[[Montreal Gazette|The Gazette]] |agency=[[Washington Post]] |page=A-1 |date=30 December 1983 |access-date=16 October 2012}}</ref> Further analysis revealed that, of several unidentified objects, nine were distant galaxies and the tenth was "[[infrared cirrus|intergalactic cirrus]]".<ref name="Chester-Caltech">{{cite web |url=http://web.ipac.caltech.edu/staff/tchester/iras/no_tenth_planet_yet.html |title=No Tenth Planet Yet From IRAS |publisher=Caltech |first=Thomas J. |last=Chester |date=5 May 1998 |archive-url=https://web.archive.org/web/20100202054332/http://web.ipac.caltech.edu/staff/tchester/iras/no_tenth_planet_yet.html |archive-date=2 February 2010}}</ref> None were found to be Solar System bodies.<ref name="Chester-Caltech"/><ref name="PlanetX">{{cite web |url=http://www.badastronomy.com/bad/misc/planetx/science.html |title=The Planet X Saga: Science |work=Bad Astronomy |first=Phil |last=Plait |author-link=Phil Plait |date=17 November 2010 |access-date=5 March 2011}}</ref>

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 [[debris disk|planetary disks]] around these stars.<ref>{{cite web |url=https://www.nasa.gov/press/2014/april/astronomical-forensics-uncover-planetary-disks-in-nasas-hubble-archive/ |title=Astronomical Forensics Uncover Planetary Disks in NASA's Hubble Archive |publisher=NASA |first1=J. D. |last1=Harrington |first2=Ray |last2=Villard |date=24 April 2014 |access-date=30 November 2016 |id=NASA Release 14-114}}</ref>

IRAS discovered six comets, out of total of 22 discoveries and recoveries of all comets that year.<ref name="springer" /><ref>{{Cite journal|url=http://adsabs.harvard.edu/full/1986QJRAS..27..102M|title=1986QJRAS..27..102M Page 102|journal=Quarterly Journal of the Royal Astronomical Society|bibcode=1986QJRAS..27..102M|access-date=2019-09-30|last1=Marsden |first1=B. G. |year=1986 |volume=27 |page=102 }}</ref> This was a lot for this period, before the launch of [[Solar and Heliospheric Observatory|SOHO]] in 1995, which would allow the discovery of many more comets in the next decade (it would detect 1000 comets in ten years).<ref>{{Cite web|url=https://www.nasa.gov/vision/universe/solarsystem/1000comet.html|title=NASA - History's Greatest Comet Hunter Discovers 1,000th Comet|website=www.nasa.gov|language=en|access-date=2019-09-30|archive-date=2020-04-23|archive-url=https://web.archive.org/web/20200423200505/https://www.nasa.gov/vision/universe/solarsystem/1000comet.html|url-status=dead}}</ref>

=== Asteroid discoveries ===
{| class="wikitable"
|+ [[Minor planet]]s discovered: 4<ref name="MPC-Discoverers" />
|-
| [[3200 Phaethon]] || 11 October 1983|| {{small|{{LoMP|3200|list}}}}
|-
| [[3728 IRAS]] || 23 August 1983|| {{small|{{LoMP|3728|list}}}}
|-
| {{mp|(10714) 1983 QG}} || 31 August 1983|| {{small|{{LoMP|10714|list}}}}
|-
| {{mp|(100004) 1983 VA}} || 1 November 1983|| {{small|{{LoMP|100004|list}}}}
|}

=== Comet discoveries ===
{| class="wikitable" style="font-size: 0.9em; width: 270px;"
|+ [[Comet]]s discovered: 6
|-
| [[C/1983 H1 (IRAS–Araki–Alcock)]] || 25 April 1983 || {{M+J|C/1983+H1}}
|-
| [[C/1983 J2 (IRAS)]] || 18 May 1983 || {{M+J|C/1983+J2}}
|-
| [[C/1983 N1 (IRAS)]] || 14 July 1983 || {{M+J|C/1983+N1}}
|-
| [[126P/IRAS]] || 28 July 1983 || {{M+J|126P}}
|-
| [[C/1983 O2 (IRAS)]] || 4 August 1983 || {{M+J|C/1983+O2}}
|-
| [[161P/Hartley–IRAS]] || 4 November 1983 || {{M+J|161P}}
|}

== Later surveys ==
Several infrared space telescopes have continued and greatly expanded the study of the infrared Universe, such as the [[Infrared Space Observatory]] launched in 1995, the [[Spitzer Space Telescope]] launched in 2003, and the [[Akari (satellite)|Akari]] Space Telescope launched in 2006.

A next generation of infrared space telescopes began when NASA's [[Wide-field Infrared Survey Explorer]] launched on 14 December 2009 aboard a [[Delta II]] 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 {{#time:j F Y, H:i:s e|2020-01-29T23:39:35.707+00:00}},<ref>{{cite tweet|user=LeoLabs_Space|number=1222304111527374853|date=29 January 2020|title=Our latest data on the IRAS / GGSE 4 event}}</ref> IRAS was expected to pass as closely as 12 meters <ref>{{cite tweet |user=LeoLabs_Space |number=1222547865567887361 |date = 29 January 2020 |title= Our latest update this morning for IRAS / GGSE 4 }}</ref> from the U.S. Air Force's Gravity Gradient Stabilization Experiment ([[GGSE-4]]) of 1967, another un-deorbited satellite left aloft; the 14.7-kilometer per second pass<ref>{{Cite web|url=https://www.space.com/satellite-near-collision-miss-over-pittsburgh.html|title=2 satellites will narrowly avoid colliding at 32,800 MPH over Pittsburgh on Wednesday|website=[[Space.com]] |date=28 January 2020}}</ref> 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.<ref>{{cite tweet |user=LeoLabs_Space |number=1222547875797880832 |date = 29 January 2020 |title= Adjusted calculations for larger object size }}</ref> 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.<ref>{{cite tweet|user=juliancd38|number=1222670217601601540|date=29 January 2020 |title=Trails of both IRAS and GGSE4 continue unimpeded after intersection}}</ref><ref>{{cite tweet|user=LeoLabs_Space|number=1222702184711757825|date=29 January 2020|title=Latest data following the event shows no evidence of new debris}}</ref>

== See also ==
*[[GGSE-4]]
* [[Diffuse Infrared Background Experiment]], an infrared sky survey on [[Cosmic Background Explorer|COBE]] (1989)
* [[Infrared astronomy]]
* [[List of asteroid-discovering observatories]]
* [[List of largest infrared telescopes]]
* {{section link|List of minor planet discoverers|Discovering dedicated institutions}}
*[[:Category:IRAS catalogue objects]]

== References ==
{{Reflist |35em |refs=
<ref name="springer">{{cite book |title=Dictionary of Minor Planet Names |url=https://archive.org/details/dictionaryminorp00schm |url-access=limited |publisher=[[Springer Berlin Heidelberg]] |last=Schmadel |first=Lutz D. |chapter=(3728) Iras |page=[https://archive.org/details/dictionaryminorp00schm/page/n328 315] |date=2007 |doi=10.1007/978-3-540-29925-7_3725 |isbn=978-3-540-00238-3}}</ref>

<ref name="MPC-Discoverers">{{cite web |url=http://www.minorplanetcenter.net/iau/lists/MPDiscsNum.html |title=Minor Planet Discoverers |work=Minor Planet Center |date=4 September 2016 |access-date=11 November 2016}}</ref>

}}

=== Bibliography ===
* {{cite book |url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19890004823.pdf |title=Infrared Astronomical Satellite (IRAS): Catalogs and Atlases |series=Volume 1: Explanatory Supplement |publisher=NASA Scientific and Technical Information Division |edition=2nd |editor1-first=C. A. |editor1-last=Beichman |editor2-first=G. |editor2-last=Neugebauer |editor3-first=H. J. |editor3-last=Habing |editor4-first=P. E. |editor4-last=Clegg |editor5-first=T. J. |editor5-last=Chester |date=1988 |ref={{sfnRef|Beichman|1988}}}}

== External links ==
{{Commons category|Infrared Astronomical Satellite}}
* [http://irsa.ipac.caltech.edu/Missions/iras.html IRAS website] by Caltech
* [http://sbn.psi.edu/pds/resource/imps.html IRAS Minor Planet Survey archive] by the Planetary Science Institute
* [http://wikisky.org/?img_source=IRAS IRAS survey] at WikiSky.org

{{Space observatories}}
{{Jet Propulsion Laboratory}}
{{Orbital launches in 1983}}
{{Astronomical Surveys}}
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[[Category:Asteroid surveys]]
[[Category:Astronomical surveys]]
[[Category:Discoveries by IRAS|*]]
[[Category:Minor-planet discovering observatories]]
[[Category:Infrared telescopes]]
[[Category:IRAS catalogue objects| ]]
[[Category:Space telescopes]]
[[Category:Spacecraft launched in 1983]]
[[Category:Satellites of the Netherlands]]