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Akari (ASTRO-F) is an infrared astronomy satellite developed by Japan Aerospace Exploration Agency, in cooperation with institutes of Europe and Korea. It was launched on 21 February 2006, at 21:28 UTC (06:28, 22 February JST) by M-V rocket into Earth sun-synchronous orbit. After its launch it was named Akari (明かり), which means light in Japanese. Earlier on, the project was known as IRIS (InfraRed Imaging Surveyor).

Mission typeInfrared telescope
COSPAR ID2006-005A
SATCAT no.28939
Mission duration5 years, 9 months
Spacecraft properties
Launch mass952 kg (2,099 lb)
Dimensions5.5 m × 1.9 m × 3.2 m (18.0 ft × 6.2 ft × 10.5 ft)
Power2006-02-21 21:28
Start of mission
Launch date21:28, February 21, 2006 (UTC) (2006-02-21T21:28UTC) [1]
Launch siteM-V Pad, Uchinoura Space Center
End of mission
DeactivatedNovember 24, 2011 (2011-11-24)
Orbital parameters
Reference systemGeocentric
Semi-major axis6,884 km (4,278 mi)[2]
Perigee423.9 km (263.4 mi)[2]
Apogee602.3 km (374.3 mi)[2]
Inclination98.2 degrees[2]
Period94.7 minutes[2]
RAAN305.9392 degrees[2]
Argument of perigee124.2012 degrees[2]
Mean anomaly354.1441 degrees[2]
Mean motion15.1995622 rev/day[2]
Epoch9 July 2015, 13:43:21 UTC[2]
Revolution no.50455[2]
Diameter0.67 m (2.2 ft)
Focal length4.2 m (14 ft)
Wavelengths1.7 to 180 µm (Infrared)
FIS: Far-Infrared Surveyor
IRC: Infra-Red Camera

Its primary mission was to survey the entire sky in near-, mid- and far-infrared, through its 68.5 cm (27.0 in) aperture telescope.[3]


Technical designEdit

Its designed lifespan, of far- and mid-infrared sensors, is 550 days, limited by its liquid helium coolant.[4]

Its telescope mirror is made of silicon carbide to save weight. The budget for the satellite was ¥13,4 billion (~US$110 million).[5]


By mid-August 2006, Akari finished around 50 percent of the all sky survey.[6]

By early November 2006, first (phase-1) all-sky survey finished. Second (phase-2) all-sky survey started on 10 November 2006.[7]

Due to the malfunction of sun-sensor after the launch, ejection of telescope aperture lid was delayed, resulting the coolant lifespan estimate to be shortened to about 500 days from launch. However, after JAXA estimated the remaining helium during early March 2007, observation time will be extended at least until 9 September.[8]

On 11 July 2007, JAXA informed that 90 percent of the sky was scanned twice. Also around 3,500 selected targets have been observed so far.[9]

On 26 August 2007, liquid-Helium coolant depleted, which means the completion of far- and mid-infrared observation. More than 96 percent of the sky was scanned and more than 5,000 pointed observations were done.[10]

British and Japanese project team members were awarded a Daiwa Adrian Prize in 2004, by The Daiwa Anglo-Japanese Foundation in recognition of their collaboration.[11]

During December 2007, JAXA performed orbit correction manoeuvres to bring Akari back into its ideal orbit. This was necessary because the boiled off helium led to an increase in altitude. If this would have continued energy supply would have been cut off.[12]

In May 2011, Akari suffered a major electrical failure that rendered its science instruments inoperable when the satellite is in the Earth's shadow.[3] The operation of satellite was terminated officially on 24 November 2011.[13]


The Akari All-Sky Survey Point Source Catalogues was released on 30 March 2010.[15][16][17]

Astronomy and Astrophysics, Vol. 514 (May 2010) was a feature issue of Akari's result.[18]

See alsoEdit


  1. ^ Stephen Clark (21 February 2006). "Japanese infrared space observatory goes into orbit". Spaceflightnow. Retrieved 20 February 2010.
  2. ^ a b c d e f g h i j k l "ATRO-F (AKARI) Satellite details 2006-005A NORAD 28939". N2YO. 6 July 2015. Retrieved 6 July 2015.
  3. ^ a b "JAXA Hopes To Keep Akari Going Despite Power Failure". Space News International. 27 May 2011. Retrieved 17 August 2011.
  4. ^ "The Infrared Astronomical Satellite AKARI and Nikon". Nikon. September 2007. Archived from the original on 2 March 2013. Retrieved 26 November 2011.
  5. ^ Editor (28 February 2006). "Fueling trust in rocket science". The Japan Times. Retrieved 16 May 2010.
  6. ^ Issei Yamamura (August 2006). "AKARI Mission Lifetime". AKARI Newsletter. vol. 16. Archived from the original on 25 May 2011. Retrieved 16 May 2010.
  7. ^ "The Infrared Astronomical Satellite AKARI and Nikon". Nikon. September 2007. Archived from the original on 11 May 2010. Retrieved 16 May 2010.
  8. ^ Issei Yamamura (9 March 2007). "AKARI Cryogenic Lifetime". AKARI Newsletter. vol. 18. Archived from the original on 25 May 2011. Retrieved 16 May 2010.
  9. ^ "Current Status of the AKARI Mission After one year of observations". Archived from the original on 31 July 2007. Retrieved 12 July 2007.
  10. ^ Usui, Fumihiko; Kuroda, Daisuke; MÜLler, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; Ishihara, Daisuke; Kataza, Hirokazu; Takita, Satoshi; Oyabu, Shinki; Ueno, Munetaka; Matsuhara, Hideo; Onaka, Takashi (2011). "Asteroid Catalog Using AKARI: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. ISSN 0004-6264.
  11. ^
  12. ^ Issei Yamamura (26 February 2008). "Happy Birthday, AKARI!". AKARI Newsletter. vol. 21. Archived from the original on 25 May 2011. Retrieved 16 May 2010.
  13. ^ "赤外線天文衛星「あかり」(ASTRO-F)の運用終了について" (in Japanese). JAXA. 24 November 2011. Retrieved 24 November 2011.
  14. ^ "AKARI (ASTRO-F) Results". JAXA/ISAS/LIRA. 28 November 2008. Archived from the original on 25 May 2011. Retrieved 16 May 2010.
  15. ^ "新世代の赤外線天体カタログ、日本から世界に公開へ" (Press release) (in Japanese). 30 March 2010. Archived from the original on 2 April 2010. Retrieved 30 March 2010.
  16. ^
  17. ^
  18. ^ "Astronomy and Astrophysics". 514. May 2010.

External linksEdit