Wide-field Infrared Survey Explorer
Encyclopedia
Wide-field Infrared Survey Explorer (WISE) is a NASA
infrared-wavelength
astronomical
space telescope
launched on December 14, 2009, and decommissioned/hibernated on February 17, 2011 when its transmitter was turned off. The mission launched an Earth-orbiting satellite
with a 40 cm (15.7 in) diameter infrared telescope
, which performed an all-sky astronomical survey with images in 3, 5, 12 and 22 μm wavelength range bands, over 10 months. The initial mission length was limited by its hydrogen coolant, but a secondary post-crygenic mission continued for four more months.
By October 2010, WISE hydrogen coolant and original NASA funding ran out, and the proposed WISE warm mission, using remaining functionality, was not approved by NASA. Rather than abandon the spacecraft, the NASA Planetary division stepped in with funding for a shorter fourth month mission extension called NEOWISE, to search for small solar system bodies close to Earth's orbit.
WISE served as a replacement for the Wide Field Infrared Explorer
(WIRE), which failed within hours of reaching orbit in March 1999. In certain measurements, WISE is over 1,000 times more sensitive than prior infrared space surveys such as IRAS
, AKARI
, and COBE
's DIRBE
.
During its active mission it found dozens of previously unknown asteroids every day. Over 33,500 new asteroids and comets were discovered, and over 154,000 solar system objects were observed by WISE by October 2010.
Results of the full survey are scheduled to be released by March 2012.
The first Earth Trojan asteroid
was discovered using WISE data, announced on July 27, 2011.
A new type of star
called Y dwarfs are discovered with WISE, announced August 23, 2011.
was placed in a 525 km (326.2 mi), circular, polar, sun-synchronous orbit
for its 10 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, which was avoided, and its solar cells towards the Sun. Each image covers a 47-arcminute field of view, which means a 6 arcsecond resolution. Each area of the sky was scanned at least 10 times at the equator, 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 Milky Way Galaxy, and the more distant universe. Among the objects WISE studied are asteroids, cool, dim stars such as brown dwarfs, and the most luminous infrared galaxies.
, as their temperature is too low. It was able to detect any objects warmer than 70-100 Kelvins. A Neptune
-sized object would be detectable out to 700 AU
, a Jupiter-mass
object out to one light year (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 seven to ten light years.
At the time of planning, it was estimated that WISE would detect about 300,000 main-belt asteroids, of which approximately 100,000 will be new, and some 700 near-Earth objects including about 300 undiscovered. That translates to ~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 with the interval of 3 hours.
Construction of the WISE telescope was divided between Ball Aerospace & Technologies (spacecraft, operations support), SSG Precision Optronics, Inc. (telescope, optics, scan mirror), DRS
and Rockwell
(focal planes), Lockheed Martin
(cryostat
, cooling for the telescope), and Space Dynamics Laboratory
(instruments, electronics, and testing). The program is managed through the Jet Propulsion Laboratory
.
. The spacecraft is derived from the Ball Aerospace RS-300 spacecraft architecture, particularly the NEXTSat
spacecraft built for the successful Orbital Express
mission launched on March 9, 2007. The flight system has an estimated mass of 560 kg (1,234.6 lb). The spacecraft is three-axis stabilized, with body-fixed solar arrays
. It uses a high-gain antenna
in the Ku band
to transmit to the ground through the TDRSS geostationary system. Ball also performed the testing and flight system integration.
(µJy) at 3.3, 4.7, 12, and 23 micrometres (aka micron
s). 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 micrometres 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 micrometres. On the other hand, IRAS could also observe 60 and 100 micron wavelengths, which WISE does not.
The primary mission lasts ten months: one month for checkout, six months for a full-sky survey, then an additional three months of survey until cryogenic coolant runs out. The partial second survey pass will facilitate the study of changes (e.g. orbital movement) in observed objects.
(NEO) survey program. The prospect of using WISE was proposed by NASA officials.
NASA officials told Committee staff that NASA plans to use WISE to detect near-Earth object
s in addition to performing its science goals. It was projected that WISE could detect 400 NEOs (or roughly 2 percent of the estimated NEO population of interest) within its one-year mission.
By October 2010, over 33,500 new asteroids and comets were discovered, and nearly 154,000 solar system objects were observed by WISE. Out of this total on that date, 136 new NEA, PHA, & Comets were discovered. Out of these, 19 were new potentially hazardous asteroids, celestial objects both more likely to hit Earth and cause significant destruction (not to be confused with the more common but less dangerous Near Earth object (NEO)). As of Oct 2010, there are 1,151 PHA are known, including those found by WISE.
Discovery of an ultra-cool brown dwarf
, WISEPC J045853.90+643451.9
, about 10 to 30 light years away from Earth, was announced in late 2010 based on early data. In July of 2011 it was announced that WISE had discovered the first Earth trojan asteroid
, 2010 TK7
.
of the University of California, Los Angeles
. 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:
rocket carrying the WISE spacecraft was originally scheduled for December 11, 2009. This attempt was scrubbed to correct a problem with a booster rocket steering engine. The launch was then rescheduled for December 14, 2009. The second attempt launched on time at 14:09:33 UTC (06:09 local PST) from Vandenberg Air Force Base
in California
. The rocket successfully placed the WISE spacecraft into the planned polar orbit
at an altitude of 326 miles (524.6 km) above the Earth
.
The WISE spacecraft underwent a month long checkout after launch, which 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 December 29, 2009. The first light image from WISE was released on January 6, 2010. It was an eight-second exposure taken in the direction of the Carina
constellation
showing infrared light in false color from three of WISE's four wavelength bands: Blue, green and red corresponding to 3.4, 4.6, and 12 micrometres, respectively. On January 14, 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 micrometres 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. Rather than see the 320 million dollar spacecraft abandoned, the NASA Planetary Division stepped in as an alternate source of funding in October 2010.
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
infrared-wavelength
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
astronomical
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
space telescope
Space observatory
A space observatory is any instrument in outer space which is used for observation of distant planets, galaxies, and other outer space objects...
launched on December 14, 2009, and decommissioned/hibernated on February 17, 2011 when its transmitter was turned off. The mission launched an Earth-orbiting satellite
Satellite
In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....
with a 40 cm (15.7 in) diameter infrared telescope
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....
, which performed an all-sky astronomical survey with images in 3, 5, 12 and 22 μm wavelength range bands, over 10 months. The initial mission length was limited by its hydrogen coolant, but a secondary post-crygenic mission continued for four more months.
By October 2010, WISE hydrogen coolant and original NASA funding ran out, and the proposed WISE warm mission, using remaining functionality, was not approved by NASA. Rather than abandon the spacecraft, the NASA Planetary division stepped in with funding for a shorter fourth month mission extension called NEOWISE, to search for small solar system bodies close to Earth's orbit.
WISE served as a replacement for the Wide Field Infrared Explorer
Wide Field Infrared Explorer
The Wide Field Infrared Explorer was a satellite launched on 5 March 1999 on the Pegasus XL rocket into a polar orbit between 409 km and 426 km above the Earth's surface...
(WIRE), which failed within hours of reaching orbit in March 1999. In certain measurements, WISE is over 1,000 times more sensitive than prior infrared space surveys such as IRAS
IRAS
The Infrared Astronomical Satellite was the first-ever space-based observatory to perform a survey of the entire sky at infrared wavelengths....
, AKARI
Akari
Akari is a Japanese surname and given name and term meaning "light" or "glimmer". It is also associated with:* AKARI, in astronomy, is an infrared astronomy satellite developed by JAXA, in cooperation with institutes of Europe and Korea...
, and COBE
COBE
The COsmic Background Explorer , also referred to as Explorer 66, was a satellite dedicated to cosmology. Its goals were to investigate the cosmic microwave background radiation of the universe and provide measurements that would help shape our understanding of the cosmos.This work provided...
's DIRBE
Diffuse Infrared Background Experiment
Diffuse Infrared Background Experiment was an experiment on NASA's COBE mission, to survey the diffuse infrared sky. The DIRBE instrument was an absolute radiometer with an off-axis folded-Gregorian reflecting telescope, with 19 cm diameter aperture...
.
During its active mission it found dozens of previously unknown asteroids every day. Over 33,500 new asteroids and comets were discovered, and over 154,000 solar system objects were observed by WISE by October 2010.
Results of the full survey are scheduled to be released by March 2012.
The first Earth Trojan asteroid
Earth Trojan asteroid
Earth trojans are asteroids that orbit in the vicinity of the Earth-Sun Lagrangian points and . They are named after the Trojan asteroids that are associated with the analogous Lagrangian points of Jupiter....
was discovered using WISE data, announced on July 27, 2011.
A new type of star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
called Y dwarfs are discovered with WISE, announced August 23, 2011.
Planned goals
The mission was planned to create infrared images of 99 percent of the sky, with at least eight images made of each position on the sky in order to increase accuracy. The spacecraftSpacecraft
A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....
was placed in a 525 km (326.2 mi), circular, polar, sun-synchronous orbit
Sun-synchronous orbit
A Sun-synchronous orbit is a geocentric orbit which combines altitude and inclination in such a way that an object on that orbit ascends or descends over any given point of the Earth's surface at the same local mean solar time. The surface illumination angle will be nearly the same every time...
for its 10 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, which was avoided, and its solar cells towards the Sun. Each image covers a 47-arcminute field of view, which means a 6 arcsecond resolution. Each area of the sky was scanned at least 10 times at the equator, 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
Solar System
The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
, the Milky Way Galaxy, and the more distant universe. Among the objects WISE studied are asteroids, cool, dim stars such as brown dwarfs, and the most luminous infrared galaxies.
Targets outside the Solar system
Stellar nurseries, which are covered by interstellar dust, are detectable in infrared, since at this wavelength electromagnetic radiation can penetrate the dust. Thus galaxies of the young Universe and interacting galaxies, where star formation is intensive, are bright in infrared. On this wavelength the interstellar gas clouds are also detectable, as well as protoplanetary discs, out of them it was expected to discover some thousand.Targets within the Solar system
WISE was not able to detect Kuiper belt objectsKuiper belt
The Kuiper belt , sometimes called the Edgeworth–Kuiper belt, is a region of the Solar System beyond the planets extending from the orbit of Neptune to approximately 50 AU from the Sun. It is similar to the asteroid belt, although it is far larger—20 times as wide and 20 to 200 times as massive...
, as their temperature is too low. It was able to detect any objects warmer than 70-100 Kelvins. A Neptune
Neptune
Neptune is the eighth and farthest planet from the Sun in the Solar System. Named for the Roman god of the sea, it is the fourth-largest planet by diameter and the third largest by mass. Neptune is 17 times the mass of Earth and is slightly more massive than its near-twin Uranus, which is 15 times...
-sized object would be detectable out to 700 AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
, a Jupiter-mass
Jupiter mass
Jupiter mass , is the unit of mass equal to the total mass of the planet Jupiter . Jupiter mass is used to describe masses of the gas giants, such as the outer planets and extrasolar planets. It is also used in describing brown dwarfs....
object out to one light year (63,000 AU), where it would still be within the Sun's zone of gravitational control
Hill sphere
An astronomical body's Hill sphere is the region in which it dominates the attraction of satellites. To be retained by a planet, a moon must have an orbit that lies within the planet's Hill sphere. That moon would, in turn, have a Hill sphere of its own...
. A larger object of 2–3 Jupiter masses would be visible at a distance of up to seven to ten light years.
At the time of planning, it was estimated that WISE would detect about 300,000 main-belt asteroids, of which approximately 100,000 will be new, and some 700 near-Earth objects including about 300 undiscovered. That translates to ~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
UBV photometric system
UBV photometric system, also called the Johnson system , is a wide band photometric system for classifying stars according to their colors. It is the first known standardized photoelectric photometric system. The letters U, B, and V stand for ultraviolet, blue, and visual magnitudes, which are...
. WISE would detect each typical Solar system object 10-12 times over about 36 hours with the interval of 3 hours.
Construction of the WISE telescope was divided between Ball Aerospace & Technologies (spacecraft, operations support), SSG Precision Optronics, Inc. (telescope, optics, scan mirror), DRS
DRS Technologies
DRS Technologies, Inc. is a US-based defense contractor. Previously traded on the NYSE, the company was purchased by the Italian firm Finmeccanica in October 2008.-History:...
and Rockwell
Rockwell International
Rockwell International was a major American manufacturing conglomerate in the latter half of the 20th century, involved in aircraft, the space industry, both defense-oriented and commercial electronics, automotive and truck components, printing presses, valves and meters, and industrial automation....
(focal planes), Lockheed Martin
Lockheed Martin
Lockheed Martin is an American global aerospace, defense, security, and advanced technology company with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta in March 1995. It is headquartered in Bethesda, Maryland, in the Washington Metropolitan Area....
(cryostat
Cryostat
A cryostat is a device used to maintain cold cryogenic temperatures. Low temperatures may be maintained within a cryostat by using various refrigeration methods, most commonly using cryogenic fluid bath such as liquid helium. Hence it is usually assembled into a vessel, similar in construction...
, cooling for the telescope), and Space Dynamics Laboratory
Space Dynamics Laboratory
Space Dynamics Laboratory is a nonprofit research corporation owned by Utah State University. SDL was founded in 1959 and has been responsible for the design, fabrication, and operation of sensors on over 400 payloads ranging from aircraft and rocket-borne experiments to space shuttle experiments...
(instruments, electronics, and testing). The program is managed through the Jet Propulsion Laboratory
Jet Propulsion Laboratory
Jet Propulsion Laboratory is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. The facility is headquartered in the city of Pasadena on the border of La Cañada Flintridge and Pasadena...
.
Spacecraft
The WISE spacecraft was built by Ball Aerospace and Technologies Corp. in Boulder, ColoradoBoulder, Colorado
Boulder is the county seat and most populous city of Boulder County and the 11th most populous city in the U.S. state of Colorado. Boulder is located at the base of the foothills of the Rocky Mountains at an elevation of...
. The spacecraft is derived from the Ball Aerospace RS-300 spacecraft architecture, particularly the NEXTSat
NEXTSat
NEXTSat, or Next Generation Satellite and Commodities Spacecraft is an American technology demonstration satellite which was operated as part of the Orbital Express programme. It was used as a target spacecraft for a demonstration of autonomous servicing and refuelling operations performed by the...
spacecraft built for the successful Orbital Express
Orbital Express
thumb|Orbital Express: ASTRO and NEXTSatOrbital Express was a space mission managed by the United States Defense Advanced Research Projects Agency and a team led by engineers at NASA's Marshall Space Flight Center...
mission launched on March 9, 2007. The flight system has an estimated mass of 560 kg (1,234.6 lb). The spacecraft is three-axis stabilized, with body-fixed solar arrays
Solar panels on spacecraft
Spacecraft operating in the inner solar system usually rely on the use of photovoltaic solar panels to derive electricity from sunlight. In the outer solar system, where the sunlight is too weak to produce sufficient power, radioisotope thermal generators are used as a power source.-History:The...
. It uses a high-gain antenna
High-gain antenna
A high-gain antenna is an antenna with a focused, narrow radiowave beam width. This narrow beam width allows more precise targeting of the radio signal - also known as a directional antenna...
in the Ku band
Ku band
The Kμ band is a portion of the electromagnetic spectrum in the microwave range of frequencies. This symbol refers to —in other words, the band directly below the K-band...
to transmit to the ground through the TDRSS geostationary system. Ball also performed the testing and flight system integration.
Mission
WISE surveyed the sky in four wavelengths of the infrared band, at a very high sensitivity. Its detector arrays have 5-sigma sensitivity limits of 120, 160, 650, and 2600 microjanskiesJansky
The flux unit or jansky is a non-SI unit of spectral flux density equivalent to 10−26 watts per square metre per hertz...
(µJy) at 3.3, 4.7, 12, and 23 micrometres (aka micron
Micron
Micron can refer to:*Micron, a non-SI name for micrometre*Micron , is the measurement used to express the diameter of a wool fibre.*A small curved diacritic mark above some letters, used to indicate shortness, e.g...
s). 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 micrometres 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 micrometres. On the other hand, IRAS could also observe 60 and 100 micron wavelengths, which WISE does not.
- Band 1 – 3.4 micrometres (microns) — broad-band sensitivity to stars and galaxies
- Band 2 – 4.6 micrometres — detect thermal radiation from the internal heat sources of sub-stellar objects like brown dwarfBrown dwarfBrown dwarfs are sub-stellar objects which are too low in mass to sustain hydrogen-1 fusion reactions in their cores, which is characteristic of stars on the main sequence. Brown dwarfs have fully convective surfaces and interiors, with no chemical differentiation by depth...
s - Band 3 – 12 micrometres — detect thermal radiation from asteroids
- Band 4 – 22 micrometres — sensitivity to dust in star-forming regionsStar formationStar formation is the process by which dense parts of molecular clouds collapse into a ball of plasma to form a star. As a branch of astronomy star formation includes the study of the interstellar medium and giant molecular clouds as precursors to the star formation process and the study of young...
(material with temperatures of 70–100 kelvinKelvinThe kelvin is a unit of measurement for temperature. It is one of the seven base units in the International System of Units and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all...
s)
The primary mission lasts ten months: one month for checkout, six months for a full-sky survey, then an additional three months of survey until cryogenic coolant runs out. The partial second survey pass will facilitate the study of changes (e.g. orbital movement) in observed objects.
Congressional hearing
On November 8, 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 ObjectNear-Earth object
A near-Earth object is a Solar System object whose orbit brings it into close proximity with the Earth. All NEOs have a perihelion distance less than 1.3 AU. They include a few thousand near-Earth asteroids , near-Earth comets, a number of solar-orbiting spacecraft, and meteoroids large enough to...
(NEO) survey program. The prospect of using WISE was proposed by NASA officials.
NASA officials told Committee staff that NASA plans to use WISE to detect near-Earth object
Near-Earth object
A near-Earth object is a Solar System object whose orbit brings it into close proximity with the Earth. All NEOs have a perihelion distance less than 1.3 AU. They include a few thousand near-Earth asteroids , near-Earth comets, a number of solar-orbiting spacecraft, and meteoroids large enough to...
s in addition to performing its science goals. It was projected that WISE could detect 400 NEOs (or roughly 2 percent of the estimated NEO population of interest) within its one-year mission.
Results
By May 27, 2010, WISE discovered 12,141 previously unknown asteroids, of which 64 were considered near-Earth, and 11 new comets. This grew to 113 near-Earth asteroids and 16 comets by August 26, 2010. Two unambiguous brown dwarfs have been detected, although their distances are unknown, as well as some brown dwarf candidates.By October 2010, over 33,500 new asteroids and comets were discovered, and nearly 154,000 solar system objects were observed by WISE. Out of this total on that date, 136 new NEA, PHA, & Comets were discovered. Out of these, 19 were new potentially hazardous asteroids, celestial objects both more likely to hit Earth and cause significant destruction (not to be confused with the more common but less dangerous Near Earth object (NEO)). As of Oct 2010, there are 1,151 PHA are known, including those found by WISE.
Discovery of an ultra-cool brown dwarf
Brown dwarf
Brown dwarfs are sub-stellar objects which are too low in mass to sustain hydrogen-1 fusion reactions in their cores, which is characteristic of stars on the main sequence. Brown dwarfs have fully convective surfaces and interiors, with no chemical differentiation by depth...
, WISEPC J045853.90+643451.9
WISEPC J045853.90+643451.9
CharacteristicsWhole systemApparent magnitude 18.34 ± 0.07Apparent magnitude 17.47 ± 0.05Apparent magnitude 17.41 ± 0.06Component ASpectral typeT8.5...
, about 10 to 30 light years away from Earth, was announced in late 2010 based on early data. In July of 2011 it was announced that WISE had discovered the first Earth trojan asteroid
Trojan asteroid
The Jupiter Trojans, commonly called Trojans or Trojan asteroids, are a large group of objects that share the orbit of the planet Jupiter around the Sun. Relative to Jupiter, each Trojan librates around one of the planet's two Lagrangian points of stability, and , that respectively lie 60° ahead...
, 2010 TK7
2010 TK7
2010 TK7 is the first Earth trojan asteroid to be discovered; it precedes Earth in its orbit around the Sun. Trojan objects are most easily conceived as orbiting at a Lagrangian point, a dynamically stable location 60 degrees ahead of or behind a massive orbiting body, in a type of 1:1 orbital...
.
Project milestones
The WISE Mission is led by Dr. Edward L. WrightEdward L. Wright
Edward L. Wright is an American astrophysicist and cosmologist, well known for his achievements in the COBE project and as a strong Big Bang proponent in web tutorials on cosmology and theory of relativity....
of the University of California, Los Angeles
University of California, Los Angeles
The University of California, Los Angeles is a public research university located in the Westwood neighborhood of Los Angeles, California, USA. It was founded in 1919 as the "Southern Branch" of the University of California and is the second oldest of the ten campuses...
. 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 $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 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 $208 million at this time.
- November 2004 NASA selects the Space Dynamics LaboratorySpace Dynamics LaboratorySpace Dynamics Laboratory is a nonprofit research corporation owned by Utah State University. SDL was founded in 1959 and has been responsible for the design, fabrication, and operation of sensors on over 400 payloads ranging from aircraft and rocket-borne experiments to space shuttle experiments...
at Utah State UniversityUtah State UniversityUtah State University is a public university located in Logan, Utah. It is a land-grant and space-grant institution and is accredited by the Northwest Commission on Colleges and Universities....
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 $300 million.
- 14 December 2009 WISE successfully launched from Vandenberg Air Force Base, California.
- 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 AB782010 AB782010 AB78 is a Near-Earth asteroid discovered in 2010. It's the first discovered by the Wide-field Infrared Survey Explorer space observatory of the many thousands it's expected to discover....
. - 11 February 2010 WISE detects a previously unknown comet, designated P/2010 B2 (WISE).
- 25 February 2010 WISE website reports it has surveyed over a quarter of the sky to a depth of 7 overlapping image frames.
- 10 April 2010 WISE website reports it has surveyed over half of the sky to a depth of 7 overlapping image frames.
- 26 May 2010 WISE website reports it has surveyed over three-quarters of the sky to a depth of 7 overlapping image frames.
- 16 July 2010 Press release announces that total 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 (ie. second scan of sky completed).
- 17 February 2011 WISE Spacecraft transmitter turned off at 12:00 noon PST 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 percent of the sky as seen by WISE.
- 27 July 2011 First Earth Trojan asteroidEarth Trojan asteroidEarth trojans are asteroids that orbit in the vicinity of the Earth-Sun Lagrangian points and . They are named after the Trojan asteroids that are associated with the analogous Lagrangian points of Jupiter....
discovered from WISE data. - 23 Aug 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 25C. Y dwarfs show ammonia absorption, in addition to methane and water absorption bands displayed by T dwarfs.
Status
The launch of the Delta IIDelta II
Delta II was an American space launch system, originally designed and built by McDonnell Douglas. Delta II is part of the Delta rocket family and was in service from 1989 until November 1, 2011...
rocket carrying the WISE spacecraft was originally scheduled for December 11, 2009. This attempt was scrubbed to correct a problem with a booster rocket steering engine. The launch was then rescheduled for December 14, 2009. The second attempt launched on time at 14:09:33 UTC (06:09 local PST) from Vandenberg Air Force Base
Vandenberg Air Force Base
Vandenberg Air Force Base is a United States Air Force Base, located approximately northwest of Lompoc, California. It is under the jurisdiction of the 30th Space Wing, Air Force Space Command ....
in California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
. The rocket successfully placed the WISE spacecraft into the planned polar orbit
Polar orbit
A polar orbit is an orbit in which a satellite passes above or nearly above both poles of the body being orbited on each revolution. It therefore has an inclination of 90 degrees to the equator...
at an altitude of 326 miles (524.6 km) above the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
.
The WISE spacecraft underwent a month long checkout after launch, which 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 December 29, 2009. The first light image from WISE was released on January 6, 2010. It was an eight-second exposure taken in the direction of the Carina
Carina (constellation)
Carina is a constellation in the southern sky. Its name is Latin for the keel of a ship, and it was formerly part of the larger constellation of Argo Navis until that constellation was divided in three.-Stars:...
constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
showing infrared light in false color from three of WISE's four wavelength bands: Blue, green and red corresponding to 3.4, 4.6, and 12 micrometres, respectively. On January 14, 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 micrometres 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. Rather than see the 320 million dollar spacecraft abandoned, the NASA Planetary Division stepped in as an alternate source of funding in October 2010.