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Wide-field Infrared Survey Explorer (WISE, observatory code C51, Explorer 92 and MIDEX-6) was a
NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...
infrared astronomy Infrared astronomy is a sub-discipline of astronomy which specializes in the astronomical observation, observation and analysis of astronomical objects using infrared (IR) radiation. The wavelength of infrared light ranges from 0.75 to 300 microm ...
space telescope A space telescope (also known as space observatory) is a telescope in outer space used to observe astronomical objects. Suggested by Lyman Spitzer in 1946, the first operational telescopes were the American Orbiting Astronomical Observatory, OAO ...
in the Explorers Program launched in December 2009.. . WISE discovered thousands of
minor planet According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''minor ...
s and numerous star clusters. Its observations also supported the discovery of the first Y-type brown dwarf and Earth trojan asteroid. ... . WISE performed an all-sky
astronomical survey An astronomical survey is a general celestial cartography, map or astrophotography, image of a region of the sky (or of the whole sky) that lacks a specific observational target. Alternatively, an astronomical survey may comprise a set of image ...
with images in 3.4, 4.6, 12 and 22 μm wavelength range bands, over ten months using a diameter
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 ...
in Earth orbit. After its solid hydrogen coolant depleted, it was placed in hibernation mode in February 2011. In 2013, NASA reactivated the WISE telescope to search for
near-Earth object A near-Earth object (NEO) is any small Solar System body orbiting the Sun whose closest approach to the Sun ( perihelion) is less than 1.3 times the Earth–Sun distance (astronomical unit, AU). This definition applies to the object's orbit a ...
s (NEO), such as
comet A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or Coma (cometary), coma surrounding ...
s and
asteroid An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...
s, that could collide with Earth. The reactivation mission was called Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE). As of August 2023, NEOWISE was 40% through the 20th coverage of the full sky. Science operations and data processing for WISE and NEOWISE take place at the Infrared Processing and Analysis Center at the
California Institute of Technology The California Institute of Technology (branded as Caltech) is a private research university in Pasadena, California, United States. The university is responsible for many modern scientific advancements and is among a small group of institutes ...
in
Pasadena, California Pasadena ( ) is a city in Los Angeles County, California, United States, northeast of downtown Los Angeles. It is the most populous city and the primary cultural center of the San Gabriel Valley. Old Pasadena is the city's original commerci ...
. The WISE All-Sky (WISEA) data, including processed images, source catalogs and raw data, was released to the public on 14 March 2012, and is available at the Infrared Science Archive. The NEOWISE mission was originally expected to end in early 2025 with the satellite reentering the atmosphere some time after.. However, the NEOWISE mission concluded its science survey on 31 July 2024 with the satellite expected to reenter Earth's atmosphere later the same year (2 November 2024). This decision was made due to increased solar activity hastening the decay of its orbit and the lack of an onboard propulsion system for orbital maintenance. The onboard transmitter was turned off on 8 August, marking the formal decommissioning of the spacecraft.


Mission goals

The mission was planned to create infrared images of 99% of the sky, with at least eight images made of each position on the sky in order to increase accuracy. The spacecraft was placed in a , circular, polar,
Sun-synchronous orbit A Sun-synchronous orbit (SSO), also called a heliosynchronous orbit, is a nearly polar orbit around a planet, in which the satellite passes over any given point of the planet's surface at the same local mean solar time. More technically, it is ...
for its ten-month mission, during which it has taken 1.5 million images, one every 11 seconds. The satellite orbited above the terminator, its telescope pointing always to the opposite direction to the Earth, except for pointing towards the
Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...
, which was avoided, and its solar cells towards the Sun. Each image covers a 47
arcminute A minute of arc, arcminute (abbreviated as arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of a degree. Since one degree is of a turn, or complete rotation, one arcminute is of a tu ...
field of view The field of view (FOV) is the angle, angular extent of the observable world that is visual perception, seen at any given moment. In the case of optical instruments or sensors, it is a solid angle through which a detector is sensitive to elec ...
(FoV), which means a 6
arcsecond A minute of arc, arcminute (abbreviated as arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of a degree. Since one degree is of a turn, or complete rotation, one arcminute is of a tu ...
resolution. Each area of the sky was scanned at least 10 times at the
equator The equator is the circle of latitude that divides Earth into the Northern Hemisphere, Northern and Southern Hemisphere, Southern Hemispheres of Earth, hemispheres. It is an imaginary line located at 0 degrees latitude, about in circumferen ...
; the poles were scanned at theoretically every revolution due to the overlapping of the images. The produced image library contains data on the local
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 "Sola ...
, the
Milky Way The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galax ...
, and the more distant
Universe The universe is all of space and time and their contents. It comprises all of existence, any fundamental interaction, physical process and physical constant, and therefore all forms of matter and energy, and the structures they form, from s ...
. Among the objects WISE studied are asteroids, cool and dim stars such as
brown dwarf Brown dwarfs are substellar objects that have more mass than the biggest gas giant planets, but less than the least massive main sequence, main-sequence stars. Their mass is approximately 13 to 80 Jupiter mass, times that of Jupiter ()not big en ...
s, and the most luminous infrared galaxies.


Targets within the Solar System

WISE was not able to detect Kuiper belt objects, because their temperatures are too low.
Pluto Pluto (minor-planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of Trans-Neptunian object, bodies beyond the orbit of Neptune. It is the ninth-largest and tenth-most-massive known object to directly orbit the Su ...
is the only Kuiper belt object that was detected. It was able to detect any objects warmer than 70–100 K. A
Neptune Neptune is the eighth and farthest known planet from the Sun. It is the List of Solar System objects by size, fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 t ...
-sized object would be detectable out to 700
Astronomical unit The astronomical unit (symbol: au or AU) is a unit of length defined to be exactly equal to . Historically, the astronomical unit was conceived as the average Earth-Sun distance (the average of Earth's aphelion and perihelion), before its m ...
(AU), a Jupiter mass object out to 1
light year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distance, astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by t ...
(63,000 AU), where it would still be within the Sun's zone of gravitational control. A larger object of 2–3 Jupiter masses would be visible at a distance of up to 7–10 light years. At the time of planning, it was estimated that WISE would detect about 300,000
main-belt asteroids The asteroid belt is a torus-shaped region in the Solar System, centered on the Sun and roughly spanning the space between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies called asteroi ...
, of which approximately 100,000 will be new, and some 700 Near-Earth objects (NEO) including about 300 undiscovered. That translates to about 1000 new main-belt asteroids per day, and 1–3 NEOs per day. The peak of magnitude distribution for NEOs will be about 21–22 V. WISE would detect each typical Solar System object 10–12 times over about 36 hours in intervals of 3 hours.


Targets outside the Solar System

Star formation Star formation is the process by which dense regions within molecular clouds in interstellar space—sometimes referred to as "stellar nurseries" or "star-forming regions"—Jeans instability, collapse and form stars. As a branch of astronomy, sta ...
, a process where visible light is normally obscured by interstellar dust, is detectable in
infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those ...
, since at this wavelength electromagnetic radiation can penetrate the dust. Infrared measurements from the WISE astronomical survey have been particularly effective at unveiling previously undiscovered star clusters. Examples of such embedded star clusters are Camargo 18, Camargo 440, Majaess 101, and Majaess 116. In addition, galaxies of the young Universe and interacting galaxies, where star formation is intensive, are bright in infrared. At infrared wavelengths, interstellar gas clouds are also detectable, as well as proto-planetary discs. The WISE satellite was expected to find at least 1,000 proto-planetary discs.


Spacecraft

The WISE satellite bus was built by Ball Aerospace & Technologies in
Boulder, Colorado Boulder is a List of municipalities in Colorado#Home rule municipality, home rule city in Boulder County, Colorado, United States, and its county seat. With a population of 108,250 at the 2020 United States census, 2020 census, it is the most ...
. The spacecraft was derived from the Ball Aerospace & Technologies RS-300 spacecraft architecture, particularly the NEXTSat spacecraft built for the successful Orbital Express mission launched on 9 March 2007. The flight system had an estimated mass of . The spacecraft was three-axis stabilized, with body-fixed solar arrays. It used a high-gain antenna in the Ku-band to transmit to the ground through the Tracking and Data Relay Satellite System (TDRSS) geostationary system. Ball also performed the testing and flight system integration. File:WISE 1.png, WISE spacecraft File:Wide-field Infrared Survey Explorer Instruments.jpg, Scheme of the spacecraft File:Wide-field Infrared Survey Explorer Optics.jpg, Scheme of the telescope File:Wide-field Infrared Survey Explorer Scheme.jpg, Scheme of the instruments


Telescope

Construction of the WISE telescope was divided between Ball Aerospace & Technologies (spacecraft, operations support), SSG Precision Optronics, Inc. (telescope, optics, scan mirror), DRS Technologies and
Rockwell International Rockwell International was a major American manufacturing conglomerate (company), conglomerate. It was involved in aircraft, the space industry, defense and commercial electronics, components in the automotive industry, printing presses, avioni ...
(focal planes),
Lockheed Martin The Lockheed Martin Corporation is an American Arms industry, defense and aerospace manufacturer with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta on March 15, 1995. It is headquartered in North ...
( cryostat, cooling for the telescope), and Space Dynamics Laboratory (instruments, electronics, and testing). The program was managed through the
Jet Propulsion Laboratory The Jet Propulsion Laboratory (JPL) is a Federally funded research and development centers, federally funded research and development center (FFRDC) in La Cañada Flintridge, California, Crescenta Valley, United States. Founded in 1936 by Cali ...
. The WISE instrument was built by the Space Dynamics Laboratory in
Logan, Utah Logan is a city in Cache County, Utah, United States. The 2020 United States Census, 2020 census recorded the population at 52,778. Logan is the county seat of Cache County and the principal city of the Logan metropolitan area, which includes Ca ...
.


Mission

WISE surveyed the sky in four wavelengths of the infrared band, at a very high sensitivity. Its design specified as goals that the full sky atlas of stacked images it produced have 5-sigma sensitivity limits of 120, 160, 650, and 2600 microjanskies (μJy) at 3.3, 4.7, 12, and 23 μm (aka microns). WISE achieved at least 68, 98, 860, and 5400 μJy; 5 sigma sensitivity at 3.4, 4.6, 12, and 22 μm for the WISE All-Sky data release. This is a factor of 1,000 times better sensitivity than the survey completed in 1983 by the IRAS satellite in the 12 and 23 μm bands, and a factor of 500,000 times better than the 1990s survey by the Cosmic Background Explorer (COBE) satellite at 3.3 and 4.7 μm. On the other hand, IRAS could also observe 60 and 100 μm wavelengths. * Band 1 – 3.4 μm (micrometre) – broad-band sensitivity to stars and galaxies * Band 2 – 4.6 μm – detect thermal radiation from the internal heat sources of sub-stellar objects like brown dwarfs * Band 3 – 12 μm – detect thermal radiation from asteroids * Band 4 – 22 μm – sensitivity to dust in star-forming regions (material with temperatures of 70–100
kelvin The kelvin (symbol: K) is the base unit for temperature in the International System of Units (SI). The Kelvin scale is an absolute temperature scale that starts at the lowest possible temperature (absolute zero), taken to be 0 K. By de ...
s) The primary mission lasted 10 months: one month for checkout, six months for a full-sky survey, then an additional three months of survey until the cryogenic coolant (which kept the instruments at 17 K) ran out. The partial second survey pass facilitated the study of changes (e.g. orbital movement) in observed objects.


Congressional hearing - November 2007

On 8 November 2007, the House Committee on Science and Technology's Subcommittee on Space and Aeronautics held a hearing to examine the status of NASA's Near-Earth Object (NEO) survey program. The prospect of using WISE was proposed by NASA officials. NASA officials told Committee staff that NASA planned to use WISE to detect near-Earth objects in addition to performing its science goals. It was projected that WISE could detect 400 NEOs (or roughly 2% of the estimated NEO population of interest) within its one-year mission.


Results

By October 2010, over 33,500 new asteroids and comets were discovered, and nearly 154,000 Solar System objects had been observed by WISE. Discovery of an ultra-cool brown dwarf, WISEPC J045853.90+643451.9, about 10~30 light years away from Earth, was announced in late 2010 based on early data. In July 2011, it was announced that WISE had discovered the first Earth
trojan asteroid In astronomy, a trojan is a small celestial body (mostly asteroids) that shares the orbit of a larger body, remaining in a stable orbit approximately 60° ahead of or behind the main body near one of its Lagrangian points and . Trojans can shar ...
, . Also, the third-closest star system, Luhman 16. As of May 2018, WISE / NEOWISE had also discovered 290 near-Earth objects and comets ''(see section below)''.


Project milestones

The WISE mission is led by Edward L. Wright of the
University of California, Los Angeles The University of California, Los Angeles (UCLA) is a public university, public Land-grant university, land-grant research university in Los Angeles, California, United States. Its academic roots were established in 1881 as a normal school the ...
. The mission has a long history under Wright's efforts and was first funded by NASA in 1999 as a candidate for a NASA Medium-class Explorer (MIDEX) mission under the name ''Next Generation Sky Survey'' (NGSS). The history of the program from 1999 to date is briefly summarized as follows: * January 1999 — NGSS is one of five missions selected for a Phase A study, with an expected selection in late 1999 of two of these five missions for construction and launch, one in 2003 and another in 2004. Mission cost is estimated at US$139 million at this time. * March 1999 — WIRE infrared telescope spacecraft fails within hours of reaching orbit. * October 1999 — Winners of MIDEX study are awarded, and NGSS is not selected. * October 2001 — NGSS proposal is re-submitted to NASA as a MIDEX mission. * April 2002 — NGSS proposal is accepted by the NASA Explorer office to proceed as one of four MIDEX programs for a Pre-Phase A study. * December 2002 — NGSS changes its name to ''Wide-field Infrared Survey Explorer'' (WISE). * March 2003 — NASA releases a press release announcing WISE has been selected for an Extended Phase-A study, leading to a decision in 2004 on whether to proceed with the development of the mission. * April 2003 — Ball Aerospace & Technologies is selected as the spacecraft provider for the WISE mission. * April 2004 — WISE is selected as NASA's next MIDEX mission. WISE's cost is estimated at US$208 million at this time. * November 2004 — NASA selects the Space Dynamics Laboratory at
Utah State University Utah State University (USU or Utah State) is a public university, public land grant colleges, land-grant research university with its main campus in Logan, Utah, United States. Founded in 1888 under the Morrill Land-Grant Acts as Utah's federal ...
to build the telescope for WISE. * October 2006 — WISE is confirmed for development by NASA and authorized to proceed with development. Mission cost at this time is estimated to be US$300 million. File:WISE before mating to its payload adapter.jpg, WISE being connected to its adapter for launch File:Installation of the Payload fairing around WISE.jpg, WISE during the payload fairing installation File:Delta II rocket launches with WISE.jpg,
Delta II Delta II was an expendable launch system, originally designed and built by McDonnell Douglas, and sometimes known as the Thorad Delta 1. Delta II was part of the Delta rocket family, derived directly from the Delta 3000, and entered service in ...
launch vehicle with WISE aboard File:WISE IR launch crop.jpg, Infrared image of WISE's launch from
Vandenberg AFB Vandenberg Space Force Base , previously Vandenberg Air Force Base, is a United States Space Force Base in Santa Barbara County, California. Established in 1941, Vandenberg Space Force Base is a space launch base, launching spacecraft from the ...
* 14 December 2009 — WISE successfully launched from Vandenberg Air Force Base,
California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
. * 29 December 2009 — WISE successfully jettisoned instrument cover. * 6 January 2010 — WISE first light image released. * 14 January 2010 — WISE begins its regular four wavelength survey scheduled for nine months duration. It is expected to cover 99% of the sky with overlapping images in the first 6 months and continuing with a second pass until the hydrogen coolant is exhausted about three months later. * 25 January 2010 — WISE detects a never-before-seen near Earth asteroid, designated 2010 AB78. * 11 February 2010 — WISE detects a previously unknown comet, designated P/2010 B2 (WISE). * 25 February 2010 — WISE website reports it has surveyed over 25% of the sky to a depth of 7 overlapping image frames. * 10 April 2010 — WISE website reports it has surveyed over 50% of the sky to a depth of 7 overlapping image frames. * 26 May 2010 — WISE website reports it has surveyed over 75% of the sky to a depth of 7 overlapping image frames. * 16 July 2010 — Press release announces that 100% sky coverage will be completed on 17 July 2010. About half of the sky will be mapped again before the instrument's block of solid hydrogen coolant sublimes and is exhausted. * October 2010 — WISE hydrogen coolant runs out. Start of NASA Planetary Division funded NEOWISE mission. * January 2011 — Entire sky surveyed to an image density of at least 16+ frames (i.e. second scan of sky completed). ''Hibernation'' * 17 February 2011 — WISE Spacecraft transmitter turned off at 20:00 UTC by principal investigator Ned Wright. The spacecraft will remain in hibernation without ground contacts awaiting possible future use. * 14 April 2011 — Preliminary release of data covering 57% of the sky as seen by WISE. * 27 July 2011 — First Earth trojan asteroid discovered from WISE data. * 23 August 2011 — WISE confirms the existence of a new class of brown dwarf, the Y dwarf. Some of these stars appear to have temperatures less than 300 K, close to room temperature at about 25 °C. Y dwarfs show
ammonia Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the chemical formula, formula . A Binary compounds of hydrogen, stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pu ...
absorption, in addition to
methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The abundance of methane on Earth makes ...
and
water Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...
absorption bands displayed by T dwarfs. * 14 March 2012 — Release of the WISE All-Sky data to the scientific community. * 29 August 2012 — WISE reveals millions of black-holes. * 20 September 2012 — WISE was successfully contacted to check its status. * 21 August 2013 — NASA announced it would recommission WISE with a new mission to search for asteroids. ''Reactivation'' * 19 December 2013 — NASA releases a new image taken by the reactivated WISE telescope, following an extended cooling down phase. The revived NeoWise mission is underway and collecting data. * 7 March 2014 — NASA reports that WISE, after an exhaustive survey, has not been able to uncover any evidence of " planet X", a hypothesized
planet A planet is a large, Hydrostatic equilibrium, rounded Astronomical object, astronomical body that is generally required to be in orbit around a star, stellar remnant, or brown dwarf, and is not one itself. The Solar System has eight planets b ...
within 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 "Sola ...
. * 26 April 2014 — The Penn State Center for Exoplanets and Habitable Worlds reports that WISE has found the coldest known brown dwarf, between −48 °C and −13 °C, 7.2
light year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distance, astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by t ...
s away from the Sun. * 21 May 2015 — NASA reports the discovery of WISE J224607.57-052635.0, the most luminous known galaxy in the
Universe The universe is all of space and time and their contents. It comprises all of existence, any fundamental interaction, physical process and physical constant, and therefore all forms of matter and energy, and the structures they form, from s ...
.


History


Launch

The launch of the Delta II launch vehicle carrying the WISE spacecraft was originally scheduled for 11 December 2009. This attempt was scrubbed to correct a problem with a booster rocket steering engine. The launch was then rescheduled for 14 December 2009. The second attempt launched on time at 14:09:33 UTC from Vandenberg Air Force Base in
California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
. The
launch vehicle A launch vehicle is typically a rocket-powered vehicle designed to carry a payload (a crewed spacecraft or satellites) from Earth's surface or lower atmosphere to outer space. The most common form is the ballistic missile-shaped multistage ...
successfully placed the WISE spacecraft into the planned
polar orbit A polar orbit is one in which a satellite passes above or nearly above both poles of the body being orbited (usually a planet such as the Earth, but possibly another body such as the Moon or Sun) on each revolution. It has an inclination of abo ...
at an altitude of above the Earth. WISE avoided the problem that affected Wide Field Infrared Explorer (WIRE), which failed within hours of reaching orbit in March 1999. In addition, WISE was 1,000 times more sensitive than prior surveys such as
IRAS 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 wavelengths. Launched on 25 Janu ...
, AKARI, and COBE's DIRBE.


"Cold" mission

A month-long checkout after launch found all spacecraft systems functioning normally and both the low- and high-rate data links to the operations center working properly. The instrument cover was successfully jettisoned on 29 December 2009. A first light image was released on 6 January 2010: an eight-second exposure in the Carina
constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...
showing
infrared light Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those o ...
in false color from three of WISE's four wavelength bands: Blue, green and red corresponding to 3.4, 4.6, and 12 μm, respectively. On 14 January 2010, the WISE mission started its official sky survey. The WISE group's bid for continued funding for an extended "warm mission" scored low by a NASA review board, in part because of a lack of outside groups publishing on WISE data. Such a mission would have allowed use of the 3.4 and 4.6 μm detectors after the last of cryo-coolant had been exhausted, with the goal of completing a second sky survey to detect additional objects and obtain parallax data on putative brown dwarf stars. NASA extended the mission in October 2010 to search for near-Earth objects (NEO). By October 2010, over 33,500 new asteroids and comets were discovered, and over 154,000 Solar System objects were observed by WISE. While active it found dozens of previously unknown asteroids every day. In total, it captured more than 2.7 million images during its primary mission.


NEOWISE (pre-hibernation)

In October 2010, NASA extended the mission by one month with a program called ''Near-Earth Object WISE'' (''NEOWISE''). Due to its success, the program was extended a further three months. The focus was to look for asteroids and comets close to Earth orbit, using the remaining post-cryogenic detection capability (two of four detectors on WISE work without cryogenic). In February 2011, NASA announced that NEOWISE had discovered many new objects in the Solar System, including twenty comets. During its primary and extended missions, the spacecraft delivered characterizations of 158,000 minor planets, including more than 35,000 newly discovered objects.


Hibernation and recommissioning

After completing a full scan of the asteroid belt for the NEOWISE mission, the spacecraft was put into hibernation on 1 February 2011. The spacecraft was briefly contacted to check its status on 20 September 2012. On 21 August 2013, NASA announced it would recommission NEOWISE to continue its search for near-Earth objects (NEO) and potentially dangerous asteroids. It would additionally search for asteroids that a robotic spacecraft could intercept and redirect to orbit the Moon. The extended mission would be for three years at a cost of US$5 million per year, and was brought about in part due to calls for NASA to step up asteroid detection after the Chelyabinsk meteor exploded over Russia in February 2013. NEOWISE was successfully taken out of hibernation in September 2013. With its coolant depleted, the spacecraft's temperature was reduced from — a relatively high temperature resulting from its hibernation — to an operating temperature of by having the telescope stare into deep space. Its instruments were then re-calibrated, and the first post-hibernation photograph was taken on 19 December 2013.


NEOWISE (post-hibernation)

The post-hibernation NEOWISE mission was anticipated to discover 150 previously unknown near-Earth objects and to learn more about the characteristics of 2,000 known asteroids. Few objects smaller than in diameter were detected by NEOWISE's automated detection software, known as the WISE Moving Object Processing Software (WMOPS), because it requires five or more detections to be reported. The average
albedo Albedo ( ; ) is the fraction of sunlight that is Diffuse reflection, diffusely reflected by a body. It is measured on a scale from 0 (corresponding to a black body that absorbs all incident radiation) to 1 (corresponding to a body that reflects ...
of asteroids larger than discovered by NEOWISE is 0.14. The telescope was turned on again in 2013, and by December 2013 the telescope had cooled down sufficiently to be able to resume observations. Between then and May 2017, the telescope made almost 640,000 detections of over 26,000 previously known objects including asteroids and comets. In addition, it discovered 416 new objects and about a quarter of those were near-Earth objects classification. As of July 2024, WISE / NEOWISE statistics lists a total of 399 near-Earth objects (NEOs), including and , discovered by the spacecraft: * 365 NEAs (subset of NEOs) * 66 PHAs (subset of NEAs) * 34 comets Of the 365 near-Earth asteroids (NEAs), 66 of them are considered potentially hazardous asteroids (PHAs), a subset of the much larger family of NEOs, but particularly more likely to hit Earth and cause significant destruction. NEOs can be divided into NECs (comets only) and NEAs (asteroids only), and further into subcategories such as Atira asteroids, Aten asteroids, Apollo asteroids, Amor asteroids and the potentially hazardous asteroids (PHAs). NEOWISE has provided an estimate of the size of over 1,850 near-Earth objects. NEOWISE mission was extended for two more years (1 July 2021 – 30 June 2023). NEOWISE's replacement, the next-generation NEO Surveyor, is scheduled to launch in 2028, and will greatly expand on what humans have learned, and continue to learn, from NEOWISE. "As of August 2023 NEOWISE is 40% through the 20th coverage of the full sky since the start of the Reactivation mission."'THE NEOWISE PROJECT'
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End of mission

On 13 December 2023, the Jet Propulsion Laboratory (JPL), announced that the satellite would enter a low orbit causing it to be unusable by early 2025. Increased solar activity as the sun approaches solar maximum during Solar cycle 25 was expected to increase
atmospheric drag In fluid dynamics, drag, sometimes referred to as fluid resistance, is a force acting opposite to the direction of motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers, two solid surfaces, or b ...
causing orbital decay. The satellite was expected to subsequently reenter the earth's atmosphere. On 8 August 2024, the Jet Propulsion Laboratory updated its estimate of orbital decay to sometime in late 2024 and announced that NEOWISE's science survey had ended on 31 July. NEOWISE entered and burnt up in the Earth's atmosphere at 8:49 p.m. EDT on 1 November 2024.


Data releases

On 14 April 2011, a preliminary release of WISE data was made public, covering 57% of the sky observed by the spacecraft. On 14 March 2012, a new atlas and catalog of the entire infrared sky as imaged by WISE was released to the astronomic community. On 31 July 2012, NEOWISE Post-Cryo Preliminary Data was released. A release called AllWISE, combining all data, was released on 13 November 2013. NEOWISE data is released annually. The WISE data include diameter estimates of intermediate precision, better than from an assumed albedo but not nearly as precise as good direct measurements, can be obtained from the combination of reflected light and thermal infrared emission, using a thermal model of the asteroid to estimate both its diameter and its albedo. In May 2016, technologist Nathan Myhrvold questioned the precision of the diameters and claimed systemic errors arising from the spacecraft's design. The original version of his criticism itself faced criticism for its methodology and did not pass
peer review Peer review is the evaluation of work by one or more people with similar competencies as the producers of the work (:wiktionary:peer#Etymology 2, peers). It functions as a form of self-regulation by qualified members of a profession within the ...
, but a revised version was subsequently published. The same year, an analysis of 100 asteroids by an independent group of astronomers gave results consistent with the original WISE analysis.


unWISE and CatWISE

The Allwise co-added images were intentionally blurred, which is optimal for detecting isolated point sources. This has the disadvantage that many sources are not detected in crowded regions. The unofficial, unblurred coadds of the WISE imaging (unWISE) creates sharp images and masks defects and transients. unWISE coadded images can be searched by
coordinates In geometry, a coordinate system is a system that uses one or more numbers, or coordinates, to uniquely determine and standardize the Position (geometry), position of the Point (geometry), points or other geometric elements on a manifold such as ...
on the unWISE website. unWISE images are used for the citizen science projects Disk Detective and Backyard Worlds. In 2019, a preliminary catalog was released. The catalog is called CatWISE. This catalog combines the WISE and NEOWISE data and provides photometry at 3.4 and 4.6 μm. It uses the unWISE images and the Allwise pipeline to detect sources. CatWISE includes fainter sources and far more accurate measurement of the
motion In physics, motion is when an object changes its position with respect to a reference point in a given time. Motion is mathematically described in terms of displacement, distance, velocity, acceleration, speed, and frame of reference to an o ...
of objects. The catalog is used to extend the number of discovered brown dwarfs, especially the cold and faint Y dwarfs. CatWISE is led by Jet Propulsion Laboratory (JPL),
California Institute of Technology The California Institute of Technology (branded as Caltech) is a private research university in Pasadena, California, United States. The university is responsible for many modern scientific advancements and is among a small group of institutes ...
, with funding from NASA's Astrophysics Data Analysis Program. The CatWISE preliminary catalog can be accessed through Infrared Science Archive (IRSA).


Discovered objects

In addition to numerous comets and minor planets, WISE and NEOWISE discovered many
brown dwarfs Brown dwarfs are substellar objects that have more mass than the biggest gas giant planets, but less than the least massive main-sequence stars. Their mass is approximately 13 to 80 times that of Jupiter ()not big enough to sustain nuclear fu ...
, some just a few light years from the solar system; the first Earth trojan; and the most luminous galaxies in the universe.


Nearby stars

Nearby stars discovered using WISE within 30 light years:


Brown dwarfs

The nearest brown dwarfs discovered by WISE within 20 light-years include: Before the discovery of Luhman 16 in 2013, WISE 1506+7027 at a distance of
light-year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astr ...
s was suspected to be closest brown dwarf on the
list of nearest stars This list covers all known stars, white dwarfs, brown dwarfs, and sub-brown dwarfs within of the Sun. So far, 131 such objects have been found. Only List of nearest bright stars, 22 are bright enough to be visible without a telescope, for whi ...
''(also see )''.


Directly-imaged exoplanets

Directly imaged
exoplanet An exoplanet or extrasolar planet is a planet outside the Solar System. The first confirmed detection of an exoplanet was in 1992 around a pulsar, and the first detection around a main-sequence star was in 1995. A different planet, first det ...
s first detected with WISE. See Definition of exoplanets: IAU working definition as of 2018 requires Mplanet ≤ 13 and Mplanet/Mcentral < 0.04006. Mmin and Mmax are the lower and upper mass limit of the planet in Jupiter masses.


Disks and young stars

The sensitivity of WISE in the infrared enabled the discovery of disk around young stars and old
white dwarf A white dwarf is a Compact star, stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very density, dense: in an Earth sized volume, it packs a mass that is comparable to the Sun. No nuclear fusion takes place i ...
systems. These discoveries usually require a combination of optical, near infrared and WISE or Spitzer mid-infrared observations. Examples are the red dwarf WISE J080822.18-644357.3, the brown dwarf WISEA J120037.79-784508.3 and the white dwarf LSPM J0207+3331. The NASA citizen science project Disk Detective is using WISE data. Additionally researchers used NEOWISE to discover erupting young stellar objects.


Nebulae

Researchers discovered a few nebulae using WISE. Such as the type Iax remnant Pa 30. Nebulae around the massive B-type stars BD+60° 2668 and ALS 19653, an obscured shell around the Wolf-Rayet star WR 35 and a halo around the Helix Nebula, a
planetary nebula A planetary nebula is a type of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives. The term "planetary nebula" is a misnomer because they are unrelated to planets. The ...
were also discovered with WISE.


Extragalactic discoveries

Active galactic nuclei (AGN) can be identified from their mid-infrared color. One work used for example a combination of
Gaia In Greek mythology, Gaia (; , a poetic form of ('), meaning 'land' or 'earth'),, , . also spelled Gaea (), is the personification of Earth. Gaia is the ancestral mother—sometimes parthenogenic—of all life. She is the mother of Uranus (S ...
and unWISE data to identify AGNs. Luminous infrared galaxies can be detected in the infrared. One study used SDSS and WISE to identify such galaxies. NEOWISE observed the entire sky for more than 10 years and can be used to find transient events. Some of these discovered transients are Tidal Disruption Events (TDE) in galaxies and infrared detection of
supernovae A supernova (: supernovae or supernovas) is a powerful and luminous explosion of a star. A supernova occurs during the last evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion. The original ob ...
similar to SN 2010jl.


Minor planets

WISE is credited with discovering 3,088 numbered minor planets. Examples of the mission's numbered minor planet discoveries include: * * *


Comet C/2020 F3 (NEOWISE)

On 27 March 2020, the comet Comet NEOWISE, C/2020 F3 (NEOWISE) was discovered by the WISE spacecraft. It eventually became a naked-eye comet and was widely photographed by professional and amateur astronomers. It was the brightest comet visible in the Northern Hemisphere, northern hemisphere since comet Comet Hale–Bopp, Hale-Bopp in 1997.


Gallery


Full sky views by WISE

File:WISE full sky.jpg, A full-sky view with infrared wavelengths rendered in visible light File:PIA15812 - Galaxies burn bright like high-wattage light bulbs (crop).jpg, Same full-sky view, highlighting hot, dust-obscured galaxies


Selected images by WISE

File:WISE- Andromeda.jpg, Wide-field infrared view of the Andromeda Galaxy using all four infrared detectors File:IC 342.jpg, IC 342, a normally obscured galaxy visible through infrared imaging File:WISE2010-040-rotate180.jpg, The green dot is WISEPC J045853.90+643451.9, WISE 0458+6434, which is thought to consist of two T-class brown dwarfs File:Runaway-star-zeta-ophiuchi-110125.jpg, The Stellar kinematics#Runaway stars, runaway star Zeta Ophiuchi and the bow shock formed by this massive star File:Puppis A - WISE - 609623main pia14884-full full.jpg, Puppis A, which is a supernova remnant File:Infrared Rho Ophiuchi Complex.jpg, The Rho Ophiuchi cloud complex File:PIA13451.jpg, IC 2944, Lambda Centauri nebula, a star-forming region in the Milky Way File:Helix Nebula unWISE.jpg, The Helix Nebula, a planetary nebula File:PIA19341-MilkyWayGalaxy-SpiralArmsData-WISE-20150603.jpg, WISE data used to trace the
Milky Way The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galax ...
Spiral galaxy#Spiral arms, spiral arms File:Exposing the Milky Way's "X".jpg, X-shape of the Milky Way Galactic bulge, bulge revealed by WISE


Map with nearby WISE stars


See also

* * Infrared astronomy * List of largest infrared telescopes * Nemesis (hypothetical star) * Tyche (hypothetical planet) * NEO Surveyor, a successor to NEOWISE


References


External links

* * * * * {{Portal bar, Astronomy, Stars, Spaceflight, Outer space, Solar System Wide-field Infrared Survey Explorer, Explorers Program Infrared telescopes NASA space probes Near-Earth object tracking Space telescopes Spacecraft launched by Delta II rockets Spacecraft launched in 2009 Spacecraft decommissioned in 2024 Spacecraft which reentered in 2024