Interface Region Imaging Spectrograph

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IRIS (Explorer).jpg
The Interface Region Imaging Spectrograph
NamesExplorer 94
Mission typeHeliophysics
COSPAR ID2013-033A
SATCAT no.39197
Mission durationPlanned: 2 years
Elapsed: 8 years, 3 months, 24 days
Spacecraft properties
ManufacturerLockheed Martin
Launch mass183 kg (403 lb)
Start of mission
Launch date28 June 2013, 02:27:46 (2013-06-28UTC02:27:46) UTC
RocketPegasus-XL F42
Launch siteStargazer, Vandenberg
ContractorOrbital Sciences
Orbital parameters
Reference systemGeocentric
Semi-major axis7,015.38 km (4,359.16 mi)
Perigee altitude623 km (387 mi)
Apogee altitude665 km (413 mi)
Inclination97.90 degrees
Period97.47 minutes
Epoch24 January 2015, 02:50:49 UTC[1]

The Interface Region Imaging Spectrograph (IRIS),[2] also called Explorer 94,[3] is a NASA solar observation satellite. The mission was funded through the Small Explorer program to investigate the physical conditions of the solar limb, particularly the interface region made up of the chromosphere and transition region. The spacecraft consists of a satellite bus and spectrometer built by the Lockheed Martin Solar and Astrophysics Laboratory (LMSAL), and a telescope provided by the Smithsonian Astrophysical Observatory. IRIS is operated by LMSAL and NASA's Ames Research Center.

The satellite's instrument is a high-frame-rate ultraviolet imaging spectrometer, providing one image per second at 0.3 arcsecond angular resolution and sub-ångström spectral resolution.

NASA announced on 19 June 2009 that IRIS was selected from six Small Explorer mission candidates for further study,[4] along with the Gravity and Extreme Magnetism (GEMS) space observatory.[5]

The spacecraft arrived at Vandenberg Air Force Base, California, on 16 April 2013[6] and was successfully launched on 27 June 2013 by a Pegasus-XL rocket.[7]

Science results[edit]

Video of IRIS data from a solar flare on 11 March 2015.

IRIS achieved first light on 17 July 2013.[8] NASA noted that "IRIS's first images showed a multitude of thin, fibril-like structures that have never been seen before, revealing enormous contrasts in density and temperature occur throughout this region even between neighboring loops that are only a few hundred miles apart."[8] On 31 October 2013, calibrated IRIS data and images were released on the project website.[9] An open-access article describing the satellite and initial data was published in the journal Solar Physics.[10]

Data collected from the IRIS spacecraft has shown that the interface region of the sun is significantly more complex than previously thought. This includes features described as solar heat bombs, high-speed plasma jets, nano-flares, and mini-tornadoes. These features are an important step in understanding the transfer of heat to the corona.[11]

In 2019 IRIS detected tadpole like jets coming out from the Sun according to NASA.[12]

IRIS team[edit]

Science and engineering team members include:[9]


  1. ^ "IRIS Satellite details 2013-033A NORAD 39197". N2YO. 24 January 2015. Retrieved 25 January 2015.
  2. ^ "Interface Region Imaging Spectrograph (IRIS)". NASA Space Science Data Coordinated Archive. 2013. 2013-033A.
  3. ^ "NASA's Explorer Program Satellites". NASA Space Science Data Coordinated Archive. 2014.
  4. ^ Harrington, J. D. (29 May 2008). "NASA Selects Small Explorer Investigations for Concept Studies".
  5. ^ Harrington, J. D. (19 June 2009). "NASA Awards Two Small Explorer Development Contracts".
  6. ^ Hendrix, Susan; Diller, George (17 April 2013). "NASA'S Newest Solar Satellite Arrives at Vandenberg AFB for Launch".
  7. ^ "IRIS Solar Observatory Launches, Begins Mission". 28 June 2013.
  8. ^ a b Fox, Karen C. (25 July 2013). "NASA's IRIS Telescope Offers First Glimpse of Sun's Mysterious Atmosphere". Retrieved 29 July 2013.
  9. ^ a b "Interface Region Imaging Spectrograph". Lockheed Martin Solar and Astrophysics Laboratory.
  10. ^ De Pontieu, B.; Title, A. M.; Lemen, J.; Kushner, G. D.; Akin, D. J.; et al. (July 2014). "The Interface Region Imaging Spectrograph (IRIS)". Solar Physics. 289 (7): 2733–2779. arXiv:1401.2491. Bibcode:2014SoPh..289.2733D. doi:10.1007/s11207-014-0485-y.
  11. ^ De Pontieu, B.; Rouppe van der Voort, L.; McIntosh, S. W.; Pereira, T. M. D.; Carlsson, M.; et al. (October 2014). "On the prevalence of small-scale twist in the solar chromosphere and transition region". Science. 346 (6207): 1255732. arXiv:1410.6862. Bibcode:2014Sci...346D.315D. doi:10.1126/science.1255732. PMID 25324398.
  12. ^ Garner, Rob (19 February 2019). "Tadpole-Like Jets From Sun Add New Clue to Age-Old Mystery". NASA. Retrieved 10 April 2019.

External links[edit]