Jump to content

Wide-field Infrared Survey Explorer

From Wikipedia, the free encyclopedia
This is an old revision of this page, as edited by CStyle (talk | contribs) at 02:15, 11 August 2010 (change tense). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.
Wide-Field Infrared Survey Explorer (WISE)
COSPAR ID2009-071A Edit this at Wikidata
SATCAT no.36119Edit this on Wikidata
Websitewise.ssl.berkeley.edu
Start of mission
Launch date2009-12-14 14:09:33 UTC

Wide-Field Infrared Survey Explorer (WISE) is a NASA-funded infrared-wavelength astronomical space telescope launched on 14 December 2009.[1][2][3] The Earth-orbiting satellite carries a 40-centimetre (16 in) diameter infrared-sensitive telescope, which surveyed the entire sky over the course of six months through images made in the 3 to 25 μm wavelength range. The telescope's image detectors are designed to make the survey at least 1,000 times more sensitive to infrared sky features than the sky surveys of previous major infrared space survey telescopes such as the Infrared Astronomical Satellite (IRAS), AKARI and COBE.[4] According to the principal investigator for WISE, the telescope is finding dozens of previously unknown asteroids every day.[5]

The complete mission will create 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 will be placed in a 525 km (326 mi), circular, polar, sun-synchronous orbit for its 10 month mission, during which it will take 1.5 million images, one every 11 seconds.[6] Each image will cover a 47-arcminute field of view. Each area of the sky will be scanned 10 times.[7] The image library produced will contain data on the local Solar System, the Milky Way Galaxy, and the more distant universe. Among the objects WISE will study are asteroids, cool, dim stars such as brown dwarfs, and the most luminous infrared galaxies.

Construction of the WISE telescope was divided between Ball Aerospace & Technologies Corp. (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.

WISE will also serve as a replacement for the Wide Field Infrared Explorer (WIRE) spacecraft, which failed within hours of reaching orbit in March 1999.[8]

Spacecraft

The WISE spacecraft was built by Ball Aerospace and Technologies Corp. in Boulder, Colorado. 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 (1,175 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.

Science mission

WISE will survey 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 microjanskies (µJy) at 3.3, 4.7, 12, and 23 microns.[4] 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 micron 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 microns.[4]

  • Band 1 – 3.4 microns—broad-band sensitivity to stars and galaxies
  • Band 2 – 4.6 microns—detect thermal radiation from the internal heat sources of sub-stellar objects like brown dwarfs
  • Band 3 – 12 microns—detect thermal radiation from asteroids
  • Band 4 – 22 microns—sensitivity to dust in star-forming regions (material with temperatures of 70–100 kelvins)
A scaffolding structure built around WISE allowed engineers to freeze its hydrogen coolant

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.[9]

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 Object (NEO) survey program. The prospect of using WISE was proposed by NASA officials.[10]

NASA officials told Committee staff that NASA plans to use WISE to detect near-Earth objects in addition to performing its science goals. It is projected that WISE could detect 400 NEOs (or roughly 2 percent of the estimated NEO population of interest) within its one-year mission.

WISE will not be able to detect Kuiper belt objects, as their temperature is too low.[11] It will be able to detect any objects with an internal heat source: 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.[11] A larger object of 2–3 Jupiter masses would be visible at a distance of up to seven to ten light years.[11]

WISE will 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 will detect each typical Solar system object 10-12 times over about 36 hours with the interval of 3 hours.[7]

Results

As of May 27, 2010, WISE has discovered 12,141 previously unknown asteroids, of which 64 are considered near-Earth, and 11 new comets.[12][13] Two unambiguous brown dwarfs have been detected, although their distances are unknown, as well as some brown dwarf candidates.[14]

The WISE mission's numbered minor planet discoveries are:

Project milestones

The WISE Mission is led by Dr. Edward L. Wright of the University of California, Los Angeles. The mission has a long history under Dr. 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 Laboratory at Utah State University 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 AB78.[15]
  • 11 February 2010 - WISE detects a previously unknown comet, designated P/2010 B2 (WISE).[16]
  • 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.[17] About half of the sky will be mapped again before the instrument's block of solid hydrogen coolant is exhausted.

Status

The launch of the Delta II 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.[18] 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 above the Earth.[3]

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.[19] 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 microns, respectively.[20] On January 14, 2010, the WISE mission started its official sky survey.[21] A planned release of survey data (as and overlapping set of 4 megapixel images) expected in April 2010, has been delayed until early 2011. The WISE group's bid for continued funding for an extended "warm mission" was recently 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 micron 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.

  • An infrared image of the launch of WISE on December 14, 2009, from Vandenberg Air Force Base.
    An infrared image of the launch of WISE on December 14, 2009, from Vandenberg Air Force Base.
  • This first light image is a false color infrared image of the sky in the direction of the Carina constellation.
    This first light image is a false color infrared image of the sky in the direction of the Carina constellation.
  • This sharp, wide-field view features infrared light from the spiral Andromeda Galaxy (M31).
    This sharp, wide-field view features infrared light from the spiral Andromeda Galaxy (M31).
  • Andromeda Galaxy seen by the longest-wavelength infrared detectors with 12-micron light color coded orange, and 22-micron light, red.
    Andromeda Galaxy seen by the longest-wavelength infrared detectors with 12-micron light color coded orange, and 22-micron light, red.

See also

References

  1. ^ Ray, Justin (2008-12-14). "Mission Status Center: Delta/WISE". Spaceflight Now. Retrieved 2009-12-26.
  2. ^ Rebecca Whatmore; Brian Dunbar (14 December 2009). "WISE". NASA. Retrieved 2009-12-26.{{cite web}}: CS1 maint: multiple names: authors list (link)
  3. ^ a b Clavin, Whitney (14 December 2009). "NASA's WISE Eye on the Universe Begins All-Sky Survey Mission". NASA Jet Propulsion Laboratory. Retrieved 2009-12-26.
  4. ^ a b c Mainzer, Amanda K.; Eisenhardt, Peter; Wright, Edward L.; Liu, Feng-Chuan; Irace, William; Heinrichsen, Ingolf; Cutri, Roc; Duval, Valerie (August 10, 2005). MacEwen, Howard A. (ed.). "Preliminary design of the Wide-Field Infrared Survey Explorer (WISE)" (PDF). Proceedings of the SPIE - UV/Optical/IR Space Telescopes: Innovative Technologies and Concepts II. vol.5899: 262–273. Retrieved 2010-03-05. {{cite journal}}: Cite journal requires |journal= (help)
  5. ^ "An Avalanche of Dark Asteroids". NASA SMD. 2010-03-26.
  6. ^ Griggs, Brandon (14 December 2009). "NASA launches infrared telescope to scan entire sky". CNN. Turner Broadcasting. Retrieved 2009-12-26.
  7. ^ a b Posting on Minor Planet Mailing List by Amy Mainzer, principal investigator (WISE NEO Section)
  8. ^ William Graham (2009-12-14). "ULA Delta II Successfully Launches with WISE". NASASpaceFlight.com. Retrieved 2009-12-26.
  9. ^ Rebecca Whatmore (10 December 2009). "NASA's Wide-field Infrared Survey Explorer". NASA Jet Propulsion Laboratory. Retrieved 2009-12-26.
  10. ^ United States House Committee on Science and Technology (7 November 2007). "Hearing Charter: Near-Earth Objects: Status of the Survey Program and Review of NASA's 2007 Report to Congress". SpaceRef Canada. Retrieved 2009-12-25.
  11. ^ a b c Lakdawalla, Emily (27 August 2009). "The Planetary Society Blog: "WISE Guys"". The Planetary Society. Retrieved 2009-12-26.
  12. ^ "MPC/MPO/MPS Archive". IAU Minor Planet Center. 5 June 2010. Retrieved 5 June 2010.
  13. ^ Alan Chamberlin (5 June 2010). "WISE NEA/Comet Discovery Statistics". NASA. Retrieved 5 June 2010.
  14. ^ John Matson (May 27, 2010). "WISE satellite already spots two brown dwarfs". Scientific American. Retrieved 4 June 2010.
  15. ^ Michael Cooney (26 January 2010). "NASA space telescope spots asteroid". Techworld. Retrieved 10-02-21. {{cite news}}: Check date values in: |accessdate= (help)
  16. ^ "WISE Spies a Comet with its Powerful Infrared Eye". NASA. Retrieved 10-02-11. {{cite web}}: Check date values in: |accessdate= (help)
  17. ^ NASA's WISE Mission to Complete Extensive Sky Survey
  18. ^ Whitney Clavin (December 10, 2009). "Mission News: WISE Launch Rescheduled for December 14". NASA. Retrieved 2009-12-23.
  19. ^ Whitney Clavin (29 December 2009). "NASA's WISE Space Telescope Jettisons Its Cover". NASA. Retrieved 2009-12-29.
  20. ^ "WISE 'First-Light' Image". NASA. 6 January 2010. Retrieved 2010-01-06.
  21. ^ "WISE - News & Events". NASA. 11 February 2010. Retrieved 2010-02-21.
Wikimedia Commons has media related to Wide-field Infrared Survey Explorer.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Wide-field_Infrared_Survey_Explorer&oldid=378290048"