Interface Region Imaging Spectrograph
IRIS spacecraft model.png
Interface Region Imaging Spectrograph (Explorer 94) satellite
NamesExplorer 94
IRIS
SMEX-12
Mission typeHeliophysics
OperatorNASA / Lockheed Martin
COSPAR ID2013-033A Edit this at Wikidata
SATCAT no.39197
Mission duration2 years (planned)
9 years, 2 months, 21 days (in progress)
Spacecraft properties
SpacecraftExplorer XCIV
Spacecraft typeInterface Region Imaging Spectrograph
BusIRIS
ManufacturerLockheed Martin
Launch mass200 kg (440 lb)
Start of mission
Launch date28 June 2013, 02:27:46 UTC
RocketPegasus-XL (F42)
Launch siteVandenberg, Stargazer
ContractorOrbital Sciences Corporation
Orbital parameters
Reference systemGeocentric orbit
RegimeSun-synchronous orbit
Perigee altitude623 km (387 mi)
Apogee altitude665 km (413 mi)
Inclination97.90°
Period97.47 minutes
Instruments
Interface Region Imaging Spectrograph (IRIS)
Explorer program
← NuSTAR (Explorer 93)
GEMS (Explorer) →
 

Interface Region Imaging Spectrograph (IRIS),[1] also called Explorer 94 and SMEX-12,[2] 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 (SAO). 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,[3] along with the Gravity and Extreme Magnetism (GEMS) space observatory.[4]

Mission

IRIS is intended to advance Sun-Earth connection studies by tracing the flow of energy and plasma into the corona and heliosphere for which no suitable observations exist. To achieve this IRIS obtains a high-resolution UV spectra and images of the sun's chromosphere, specifically on the non-thermal energy that creates the corona and the solar wind. IRIS seeks to determine: (1) the types of non-thermal energy which dominate in the chromosphere and beyond; (2) the means by which the chromosphere regulates mass and energy supply to the corona and heliosphere; and, (3) how magnetic flux and matter rise through the lower solar atmosphere, and the role played by flux emergence in flares and mass ejections. To answer these questions, IRIS utilize a single instrument, a multi-channel imaging spectrograph.[1]

Launch

IRIS launch preparations
IRIS launch preparations

The spacecraft arrived at Vandenberg Air Force Base, California, on 16 April 2013 and was successfully deployed from an Orbital L-1011 carrier aircraft flying over the Pacific Ocean at an altitude of 12,000 m (39,000 ft), roughly 160 km (99 mi) northwest of Vandenberg. The launch vehicle was dropped at 02:27:46 UTC on 28 June 2013 (7:27 p.m. PDT on 27 June 2013) by a Pegasus-XL launch vehicle.[5][6][1]

Experiment

Interface Region Imaging Spectrograph (IRIS)

The IRIS instrument is a multi-channel imaging spectrograph with a 20 cm (7.9 in) ultraviolet telescope. IRIS obtains a spectra along a slit (1/3 arcsecond wide), and slit-jaw images. The charge-coupled device (CCD) detectors has 1/6 arcsecond pixels. IRIS will have an effective spatial resolution between 0.33 and 0.40 arcsecond and a maximum field of view (FoV) of 120 arcseconds. The far-ultraviolet channel covers 133.2-135.8 nm and 139.0-140.6 nm with a 4 nm resolution and an effective area of 2.8 cm2 (0.43 sq in). The near-ultraviolet channel covers 278.5-283.5 nm with a 8 nm resolution and an effective area of 0.3 cm2 (0.047 sq in). Slit-jaw imaging has four passbands: 133.5 nm and 140.0 nm with a 4 nm bandpass each; and 279.6 nm and 283.1 nm with a 0.4 nm bandpass each. IRIS has a high data rate (0.7 Mbit/s on average) so that the baseline cadence is 5 seconds for slit-jaw images and 1 second for six spectral windows, including rapid rastering to map solar regions.[7]

Science results

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

Science and engineering team members include:[9]

See also

References

  1. ^ a b c "Display: IRIS (Explorer 94) 2013-033A". NASA. 28 October 2021. Retrieved 12 December 2021. Public Domain This article incorporates text from this source, which is in the public domain.
  2. ^ "NASA's Explorer Program Satellites". NASA. 22 July 2019. Retrieved 12 December 2021. Public Domain This article incorporates text from this source, which is in the public domain.
  3. ^ Harrington, J. D. (29 May 2008). "NASA Selects Small Explorer Investigations for Concept Studies". NASA. Public Domain This article incorporates text from this source, which is in the public domain.
  4. ^ Harrington, J. D. (19 June 2009). "NASA Awards Two Small Explorer Development Contracts". NASA. Public Domain This article incorporates text from this source, which is in the public domain.
  5. ^ Hendrix, Susan; Diller, George (17 April 2013). "NASA'S Newest Solar Satellite Arrives at Vandenberg AFB for Launch". NASA. Public Domain This article incorporates text from this source, which is in the public domain.
  6. ^ "IRIS Solar Observatory Launches, Begins Mission". NASA. 28 June 2013. Public Domain This article incorporates text from this source, which is in the public domain.
  7. ^ "Experiment: Interface Region Imaging Spectrograph (IRIS)". NASA. 28 October 2021. Retrieved 12 December 2021. Public Domain This article incorporates text from this source, which is in the public domain.
  8. ^ a b Fox, Karen C. (25 July 2013). "NASA's IRIS Telescope Offers First Glimpse of Sun's Mysterious Atmosphere". NASA. Retrieved 29 July 2013. Public Domain This article incorporates text from this source, which is in the public domain.
  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. S2CID 53596913.
  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. S2CID 51601695.
  12. ^ "Tadpole-Like Jets From Sun Add New Clue to Age-Old Mystery". NASA. 19 February 2019. Retrieved 10 April 2019. Public Domain This article incorporates text from this source, which is in the public domain.