Interface Region Imaging Spectrograph

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IRIS (Explorer 94)
IRIS (Explorer 94)
Type: Space telescope
Country: United StatesUnited States United States
Operator: National Aeronautics and Space AdministrationNASA NASA
COSPAR-ID : 2013-033A
Mission dates
Dimensions: 200 kg
Begin: June 28, 2013, 02:27 UTC
Starting place: Vandenberg Air Force Base /
Western Air Drop Zone (WADZ)
Launcher: Pegasus-XL
Status: in orbit
Orbit data
Orbit inclination : 97.9 °
Apogee height :  596 km
Perigee height :  666 km

Interface Region Imaging Spectrograph ( IRIS ) is a space telescope for exploring the solar atmosphere . IRIS is a satellite in the Explorer program of NASA . After reaching orbit, IRIS was given the additional designation Explorer 94 .

task

IRIS was selected from six candidates on June 19, 2009 along with the later deleted Gravity and Extreme Magnetism SMEX for the SMEX (Small Explorer) program. The Lockheed Martin Solar and Astrophysics Laboratory (LMSAL) was in charge of IRIS . The satellite was built by the Lockheed Martin Solar and Astrophysics Laboratory (LMSAL) and is operated jointly by NASA's Ames Research Center .

The task of IRIS is to research the outer areas of the solar atmosphere. IRIS is the energy and plasma flow through the Chromosphere and the transition region (engl. Interface region ) in the solar corona in the ultraviolet range and examine by means of Figure spectrometry. This provides information about the energy transport into the corona and the solar wind , which contribute to an understanding of this dynamic region of the sun and other stars, which has not been investigated in detail so far.

The telescope can only cover about one percent of the sun's surface per image, but achieves a spatial resolution of 240 km. IRIS thus complements the images from the Solar Dynamics Observatory (SDO) research satellite, which provides complete images of the sun in lower resolution, for example to investigate active regions.

The UV telescope enables the observation of solar matter in the temperature range from 5000  K to 65,000 K and solar flares up to 10 million K. This range was chosen in order to record material in the photosphere, the transition layer and the chromosphere. The instrument takes an image every five to ten seconds and spectra every one to two seconds.

construction

Structure of the IRIS satellite

The IRIS satellite consists of a disc-shaped satellite structure that contains the systems for power supply, communication, control and attitude regulation and carries the UV telescope. The energy is supplied by two fold-out solar cell arms . These are aligned with the entire satellite via three-axis stabilization towards the sun. The data is transmitted to the ground station via an X-band radio link at a data transmission rate of up to 10 Mbit / second . With a mass of 200 kg, the satellite has a height of 2.1 m and with unfolded solar cell arms a span of 3.7 m.

The IRIS-satellite has only a research tool: an imaging UV - spectrometer with 20 cm aperture and a high frame rate. It delivers one image per second with a spatial resolution of 0.3 arc seconds and a spectral resolution  in the sub- Ångström range. The telescope was provided by the Smithsonian Astrophysical Observatory , while the spectrometer and imaging UV camera were designed and built by LMSAL.

A guide telescope is also mounted parallel to the main instrument for precise alignment of the observatory .

Mission history

The satellite was delivered to Vandenberg Air Force Base in California on April 16, 2013 and mounted on the Pegasus XL launcher on May 29 . An L-1011 TriStar from Orbital Sciences with the designation Stargazer served as the carrier aircraft . The carrier aircraft took off at 01:27 UTC from Vandenberg Air Force Base on June 28 (or June 27 local time) and flew to the Point Arguello Western Air Drop Zone (WADZ) at 36 ° 0 ′  N , 123 ° 0 ′  W . There the Pegasus rocket was dropped at 02:27 UTC from an altitude of 39,000  ft (approx. 11,900  m ), the engines fired five seconds later. The three-stage Pegasus took about 13 minutes to bring the satellite into its intended orbit and successfully launch it there. The first image of the probe was published on July 25, 2013.

Originally it was only supposed to operate for two years, but the mission was extended to September 2018 in September 2016.

  • IRIS preparing for launch

  • The Pegasus XL rocket is being prepared for IRIS

  • IRIS is mounted on the launcher

Web links

Commons : Interface Region Imaging Spectrograph  - collection of images, videos and audio files

Individual evidence

  1. ^ NASA Selects Small Explorer Investigations for Concept Studies. NASA, May 29, 2008, accessed July 23, 2013 .
  2. ^ NASA Awards Two Small Explorer Development Contracts. NASA, June 19, 2009, accessed July 23, 2013 .
  3. ↑ NASA IRIS Homepage - Overview. NASA, June 5, 2013, accessed July 23, 2013 .
  4. ↑ a b c NASA IRIS Homepage - IRIS Spacecraft. NASA, June 5, 2013, accessed July 23, 2013 .
  5. ^ William Graham: Orbital's Pegasus XL successfully lofts IRIS spacecraft. nasaspaceflight.com, June 27, 2013, accessed on July 1, 2013 (English, due to the time difference between the USA and UTC, the article is still dated June 27).
  6. ↑ Karen C. Fox: NASA's IRIS Telescope Offers First Glimpse of Sun's Mysterious Atmosphere. NASA, July 25, 2013, accessed July 30, 2013 .
  7. ↑ Chris Bergin, William Graham: IRIS mission gains extension and Chilean cooperation. nasaspacerflight.com, September 19, 2016, accessed September 20, 2016 .