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Akari (satellite)

Akari
Mission type Infrared telescope
Operator JAXA
COSPAR ID 2006-005A
SATCAT № 28939
Website global.jaxa.jp/projects/sat/astro_f/
Mission duration 5 years, 9 months
Spacecraft properties
Manufacturer ISAS
Launch mass 952 kg (2,099 lb)
Dimensions 5.5 m × 1.9 m × 3.2 m (18.0 ft × 6.2 ft × 10.5 ft)
Power 2006-02-21 21:28
Start of mission
Launch date 21:28, February 21, 2006 (2006-02-21T21:28)
Rocket M-V-8
Launch site M-V Pad, Uchinoura Space Center
End of mission
Disposal decommissioned
Deactivated November 24, 2011 (2011-11-24)
Orbital parameters
Reference system Geocentric
Regime Sun-synchronous
Semi-major axis 6,884 km (4,278 mi)
Eccentricity 0.0129527
Perigee 423.9 km (263.4 mi)
Apogee 602.3 km (374.3 mi)
Inclination 98.2 degrees
Period 94.7 minutes
RAAN 305.9392 degrees
Argument of perigee 124.2012 degrees
Mean anomaly 354.1441 degrees
Mean motion 15.1995622 rev/day
Epoch 9 July 2015, 13:43:21 UTC
Revolution number 50455
Main
Type Ritchey–Chrétien
Diameter 0.67 m (2.2 ft)
Focal length 4.2 m (14 ft)
Wavelengths 1.7 to 180 µm (Infrared)
Instruments
FIS: Far-Infrared Surveyor
IRC: Infra-Red Camera

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).

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.

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

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

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

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

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.

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.

On 26 August 2007, liquid-Helium coolant depleted, which means the completion of far- and mid-infrared observation. 94 percent of the sky was scanned and more than 5,000 pointed observations were done.

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.


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