Swift Gamma-Ray Burst Mission

Swift Gamma-Ray Burst Mission
Names Explorer-84
MIDEX-3
Mission type Gamma-ray astronomy
Operator NASA / GSFC
COSPAR ID 2004-047A
SATCAT № 28485
Website swift.gsfc.nasa.gov
Mission duration Planned: 2 years[1][2]
Elapsed: 11 years, 2 months and 29 days
Spacecraft properties
Bus LEOStar-3
Manufacturer Spectrum Astro
Launch mass 1,467 kg (3,234 lb)[3]
Dry mass 613 kg (1,351 lb)
Payload mass 843 kg (1,858 lb)
Dimensions 5.6 × 5.4 m (18.5 × 17.75 ft)[4]
Power 2132 W[3]
Start of mission
Launch date November 20, 2004, 17:16 UTC (2004-11-20UTC17:16Z)
Rocket Delta II 7320-10C
Launch site Cape Canaveral SLC-17
Contractor United Launch Alliance
Orbital parameters
Reference system Geocentric
Regime Low Earth
Semi-major axis 6,939 km (4,312 mi)
Eccentricity 0.0011647
Perigee 560.1 km (348.0 mi)
Apogee 576.3 km (358.1 mi)
Inclination 20.5575 degrees
Period 95.9 minutes
RAAN 62.5406 degrees
Argument of perigee 261.5597 degrees
Mean anomaly 98.3516 degrees
Mean motion 15.01896267 rev/day
Epoch July 7, 2015, 09:19:41 UTC[5]
Revolution number 58103
Main telescope
Type BAT: Coded mask
XRT: Wolter type I
UVOT: Ritchey-Chrétien
Diameter XRT: 51 cm (20 in)
UVOT: 30 cm (12 in)
Focal length UVOT: 3.5 m (11 ft)
Collecting area BAT: 5,200 cm2 (810 sq in)
XRT: 135 cm2 (20.9 sq in)
Wavelengths γ-ray / X-ray / UV / Visible


Swift mission patch


Medium Explorer program
 WMAP THEMIS
Animation showing Swift moving into sunlight and past the Earth to end facing out into space

The Swift Gamma-Ray Burst Mission consists of a robotic spacecraft called Swift, which was launched into orbit on November 20, 2004, at 17:16:00 UTC on a Delta II 7320-10C expendable launch vehicle. Headed by Principal Investigator Dr. Neil Gehrels, NASA Goddard Space Flight Center, the mission was developed in a joint partnership between Goddard and an international consortium from the United States, United Kingdom, and Italy. It is part of NASA's Medium Explorer program (MIDEX). The mission is operated at Pennsylvania State University.

Overview

Swift is a multi-wavelength space observatory dedicated to the study of gamma-ray bursts (GRBs). Its three instruments work together to observe GRBs and their afterglows in the gamma-ray, X-ray, ultraviolet, and optical wavebands.

Based on continuous scans of the area of the sky with one of the instrument's monitors, Swift uses momentum wheels to autonomously slew into the direction of possible GRBs. The name "Swift" is not a mission-related acronym, but rather a reference to the instrument's rapid slew capability, and the nimble bird of the same name.[6] All of Swift's discoveries are transmitted to the ground and those data are available to other observatories which join Swift in observing the GRBs.

In the time between GRB events, Swift is available for other scientific investigations, and scientists from universities and other organizations can submit proposals for observations.

The Swift Mission Operation Center (MOC), where commanding of the satellite is performed, is located in State College, Pennsylvania and operated by the Pennsylvania State University and industry subcontractors. The Swift main ground station is located at the Broglio Space Centre near Malindi on the coast of Eastern Kenya, and is operated by the Italian Space Agency. The Swift Science Data Center (SDC) and archive are located at the Goddard Space Flight Center outside Washington D.C. The UK Swift Science Data Centre is located at the University of Leicester.

The Swift spacecraft bus was built by Spectrum Astro, which was later acquired by General Dynamics Advanced Information Systems,[7] which was in turn acquired by Orbital Sciences Corporation.

Instruments

Burst Alert Telescope (BAT)

The BAT detects GRB events and computes its coordinates in the sky. It covers a large fraction of the sky (over one steradian fully coded, three steradians partially coded; by comparison, the full sky solid angle is 4π or about 12.6 steradians). It locates the position of each event with an accuracy of 1 to 4 arc-minutes within 15 seconds. This crude position is immediately relayed to the ground, and some wide-field, rapid-slew ground-based telescopes can catch the GRB with this information. The BAT uses a coded-aperture mask of 52,000 randomly placed 5 mm lead tiles, 1 metre above a detector plane of 32,768 four mm CdZnTe hard X-ray detector tiles; it is purpose-built for Swift. Energy range: 15–150 keV.[8]

X-ray Telescope (XRT)

The XRT can take images and perform spectral analysis of the GRB afterglow. This provides more precise location of the GRB, with a typical error circle of approximately 2 arcseconds radius. The XRT is also used to perform long-term monitoring of GRB afterglow light-curves for days to weeks after the event, depending on the brightness of the afterglow. The XRT uses a Wolter Type I X-ray telescope with 12 nested mirrors, focused onto a single MOS charge-coupled device (CCD) similar to those used by the XMM-Newton EPIC MOS cameras. On-board software allows fully automated observations, with the instrument selecting an appropriate observing mode for each object, based on its measured count rate. The telescope has an energy range of 0.2 - 10 keV.[9]

Ultraviolet/Optical Telescope (UVOT)

After Swift has slewed towards a GRB, the UVOT is used to detect an optical afterglow. The UVOT provides a sub-arcsecond position and provides optical and ultra-violet photometry through lenticular filters and low resolution spectra (170–650 nm) through the use of its optical and UV grisms. The UVOT is also used to provide long-term follow-ups of GRB afterglow lightcurves. The UVOT is based on the XMM-Newton mission's Optical Monitor (OM) instrument, with improved optics and upgraded onboard processing computers.[10]

On November 9, 2011, UVOT photographed the asteroid 2005 YU55 as the asteroid made a close flyby of the Earth.[11] On June 3, 2013, UVOT unveiled a massive ultraviolet survey of the nearby Magellanic Clouds.[12]

Mission goals

The Swift mission has four key scientific objectives:

Mission history

UVOT's "first light" picture.

Swift was launched on November 20, 2004, and reached a near-perfect orbit of 586 × 601 km (364 × 373 mi) altitude, with an inclination of 20°.

On December 4, an anomaly occurred during instrument activation when the Thermo-Electric Cooler (TEC) Power Supply for the X-Ray Telescope did not turn on as expected. The XRT Team at Leicester and Penn State University were able to determine on December 8 that the XRT would be usable even without the TEC being operational. Additional testing on December 16 did not yield any further information as to the cause of the anomaly.

On December 17 at 07:28:30 UT, the Swift Burst Alert Telescope (BAT) triggered and located on board an apparent gamma-ray burst during launch and early operations.[13] The spacecraft did not autonomously slew to the burst since normal operation had not yet begun, and autonomous slewing was not yet enabled. Swift had its first GRB trigger during a period when the autonomous slewing was enabled on January 17, 2005, at about 12:55 UTC. It pointed the XRT telescope to the on-board computed coordinates and observed a bright X-ray source in the field of view.[14]

On February 1, 2005, the mission team released the first light picture of the UVOT instrument and declared Swift operational.

As of May 2010, Swift has detected more than 500 GRBs, X-ray afterglows for more than 90% of them, and optical afterglows for more than 50% of them.[15]

By October 2013 Swift had detected more than 800 GRBs.[16]

As of February 2015, Swift is still functioning well and has 942 GRB detections in total to its credit, with around 15 GRBs detected in 2015 so far.[17]

Notable detections

See also

References

  1. "NASA Swift Mission Extended for 4 More Years". Omitron. Archived from the original on April 8, 2008. Retrieved April 7, 2008.
  2. "Omitron flight operations for NASA Swift mission extended for two additional years". Omitron. February 10, 2009. Retrieved December 13, 2014.
  3. 1 2 "Swift: Space-based Gamma-Ray Observatory" (PDF). Orbital ATK. 2014. Retrieved July 7, 2015.
  4. "Swift Facts and FAQ". Sonoma State University. March 28, 2008. Retrieved July 7, 2015.
  5. "SWIFT Satellite details 2004-047A NORAD 28485". N2YO. July 7, 2015. Retrieved July 7, 2015.
  6. J.D. Myers (September 26, 2007). "Swift Guest Investigator Program Frequently Asked Questions". NASA/GSFC. Retrieved May 2, 2009.
  7. "Swift". Spectrum Astro.
  8. J.D. Myers (February 28, 2006). "Swift's Burst Alert Telescope (BAT)". NASA/ GSFC. Retrieved May 2, 2009.
  9. J.D. Myers (August 15, 2008). "Swift's X-Ray Telescope (XRT)". NASA/ GSFC. Retrieved May 2, 2009.
  10. J.D. Myers (December 14, 2006). "Swift's Ultraviolet/Optical Telescope (UVOT)". NASA / GSFC. Retrieved May 2, 2009.
  11. Swift Captures Flyby of Asteroid 2005 YU55. NASA press release, November 11, 2011. Retrieved November 22, 2011.
  12. . NASA press release. June 3, 2013.
  13. Ed Fenimore (December 17, 2004). "GRB041217: The First GRB Located On-Board Swift". Los Alamos National Laboratory. Retrieved May 2, 2009.
  14. "GCN GRB Observation Report: GRB050117, Swift XRT Position". Gamma-ray Coordinates Network. NASA. January 17, 2005. Retrieved July 7, 2015.
  15. J.D. Myers (May 27, 2011). "The Swift Gamma-Ray Burst Mission". NASA/GSFC. Retrieved July 17, 2011.
  16. "Swift GRB Table Stats". NASA.gov. Retrieved November 10, 2013.
  17. "Swift GRB Table". NASA.gov. Retrieved February 15, 2015.
  18. David Whitehouse (May 11, 2005). "Blast hints at black hole birth". BBC News. Retrieved July 12, 2011.
  19. Bloom, Joshua (May 31, 2005). "Astronomers hot on the trail of nature's exotic flashers". UC Berkeley News. Retrieved July 7, 2015.
  20. Naeye, Robert (May 21, 2008). "NASA's Swift Satellite Catches a Star Going 'Kaboom!'" (Press release). Goddard Space Flight Center. Retrieved May 2, 2009.
  21. Harrington, J. D. (March 20, 2008). "NASA Satellite Detects Naked-Eye Explosion Halfway Across Universe" (Press release). Goddard Space Flight Center. Retrieved May 2, 2009.
  22. "More Observations of GRB 090423, the Most Distant Known Object in the Universe". Universe Today. Retrieved February 23, 2010.
  23. Garner, Robert (September 19, 2008). "NASA's Swift Catches Farthest Ever Gamma-Ray Burst". NASA. Retrieved November 3, 2008.
  24. Reddy, Francis (April 28, 2009). "New Gamma-Ray Burst Smashes Cosmic Distance Record" (Press release). Goddard Space Flight Center. Retrieved May 2, 2009.
  25. Amos, Jonathan (May 25, 2011). "Cosmic distance record 'broken'". BBC News. Retrieved May 25, 2011.
  26. Francis Reddy (April 19, 2010). "NASA's Swift Catches 500th Gamma-ray Burst". Goddard Space Flight Center. Retrieved June 17, 2011.
  27. Alicia Chang (June 16, 2011). "Black Hole Devours Star: Source Of Mysterious Flash In Distant Galaxy Determined". The Huffington Post. Retrieved June 17, 2011.
  28. Agence France-Presse (June 17, 2011). "Black hole eats star, triggers gamma-ray flash". Cosmos. Retrieved June 17, 2011.
  29. Reddy, Francis (October 5, 2012). "NASA's Swift Satellite Discovers a New Black Hole in our Galaxy". Goddard Space Flight Center. Retrieved November 10, 2013.
  30. Sbarufatti, Boris (September 17, 2012). "Swift J174510.8-262411 (to be known as Sw J1745-26): 0.5 Crab and rising". The Astronomer's Telegram. Retrieved November 10, 2013.
  31. Belloni, Tomaso (October 3, 2012). "Swift J174510.8-262411 in the hard intermediate state". The Astronomer's Telegram. Retrieved November 10, 2013.
  32. Young, Monica (May 10, 2013). "A Cosmic Sleight of Hand". Sky & Telescope. Retrieved November 10, 2013.
  33. Reddy, Francis (May 3, 2013). "NASA's Fermi, Swift See 'Shockingly Bright' Burst". NASA.gov. Retrieved November 10, 2013.
  34. Reddy, Francis (September 30, 2014). "NASA's Swift Mission Observes Mega Flares from a Mini Star". NASA/Goddard Space Flight Center. Retrieved March 19, 2015.

Further reading

External links

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