![]() Artist's conception of Akari | |
Mission type | Infrared telescope |
---|---|
Operator | JAXA |
COSPAR ID | 2006-005A |
SATCAT no. | 28939 |
Website | global |
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 | 21:28,21 February 2006(UTC) [1] |
Rocket | M-V, mission M-V-8 |
Launch site | M-V Pad, Uchinoura Space Center |
End of mission | |
Disposal | decommissioned |
Deactivated | 24 November 2011 |
Orbital parameters | |
Reference system | Geocentric |
Regime | Sun-synchronous |
Semi-major axis | 6,884 km (4,278 mi) [2] |
Eccentricity | 0.0129527 [2] |
Perigee altitude | 423.9 km (263.4 mi) [2] |
Apogee altitude | 602.3 km (374.3 mi) [2] |
Inclination | 98.2 degrees [2] |
Period | 94.7 minutes [2] |
RAAN | 305.9392 degrees [2] |
Argument of perigee | 124.2012 degrees [2] |
Mean anomaly | 354.1441 degrees [2] |
Mean motion | 15.1995622 rev/day [2] |
Epoch | 9 July 2015, 13:43:21 UTC [2] |
Revolution no. | 50455 [2] |
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. [3]
Its designed lifespan, of far- and mid-infrared sensors, was 550 days, limited by its liquid helium coolant. [4]
Its telescope mirror was 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 in the coolant lifespan estimate being shortened to about 500 days from launch. However, after JAXA estimated the remaining helium during early March 2007, observation time was 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]
A limited observation 'warm' programme continued with just NIR.
In May 2011, Akari suffered a major electrical failure and the batteries could not take full charge from the solar panels. As a result, its science instruments were rendered inoperable when the satellite was 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]
A space telescope or space observatory is a telescope in outer space used to observe astronomical objects. Suggested by Lyman Spitzer in 1946, the first operational telescopes were the American Orbiting Astronomical Observatory, OAO-2 launched in 1968, and the Soviet Orion 1 ultraviolet telescope aboard space station Salyut 1 in 1971. Space telescopes avoid the filtering and distortion (scintillation) of electromagnetic radiation which they observe, and avoid light pollution which ground-based observatories encounter. They are divided into two types: Satellites which map the entire sky, and satellites which focus on selected astronomical objects or parts of the sky and beyond. Space telescopes are distinct from Earth imaging satellites, which point toward Earth for satellite imaging, applied for weather analysis, espionage, and other types of information gathering.
Infrared astronomy is a sub-discipline of astronomy which specializes in the observation and analysis of astronomical objects using infrared (IR) radiation. The wavelength of infrared light ranges from 0.75 to 300 micrometers, and falls in between visible radiation, which ranges from 380 to 750 nanometers, and submillimeter waves.
The Infrared Astronomical Satellite (IRAS) was the first space telescope to perform a survey of the entire night sky at infrared wavelengths. Launched on 25 January 1983, its mission lasted ten months. The telescope was a joint project of the United States (NASA), the Netherlands (NIVR), and the United Kingdom (SERC). Over 250,000 infrared sources were observed at 12, 25, 60, and 100 micrometer wavelengths.
The Spitzer Space Telescope, formerly the Space Infrared Telescope Facility (SIRTF), was an infrared space telescope launched in 2003. Operations ended on 30 January 2020. Spitzer was the third space telescope dedicated to infrared astronomy, following IRAS (1983) and ISO (1995–1998). It was the first spacecraft to use an Earth-trailing orbit, later used by the Kepler planet-finder.
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The Herschel Space Observatory was a space observatory built and operated by the European Space Agency (ESA). It was active from 2009 to 2013, and was the largest infrared telescope ever launched until the launch of the James Webb Space Telescope in 2021. Herschel carries a 3.5-metre (11.5 ft) mirror and instruments sensitive to the far infrared and submillimetre wavebands (55–672 µm). Herschel was the fourth and final cornerstone mission in the Horizon 2000 programme, following SOHO/Cluster II, XMM-Newton and Rosetta.
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Wide-field Infrared Survey Explorer is a NASA infrared astronomy space telescope in the Explorers Program. It was launched in December 2009, and placed in hibernation mode in February 2011, before being re-activated in 2013 and renamed the Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE). WISE discovered thousands of minor planets and numerous star clusters. Its observations also supported the discovery of the first Y-type brown dwarf and Earth trojan asteroid.
2456 Palamedes is a large Jupiter trojan from the Greek camp, approximately 90 kilometers in diameter. It was discovered on 30 January 1966, by astronomers at the Purple Mountain Observatory in Nanking, China. The assumed C-type asteroid has a rotation period of 7.24 hours and belongs to the 50 largest Jupiter trojans. It was named after Palamedes from Greek mythology.
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3544 Borodino (prov. designation: 1977 RD4) is a stony background asteroid from the inner regions of the asteroid belt, approximately 9 kilometers (5.6 miles) in diameter. It was discovered on 7 September 1977, by Soviet astronomer Nikolai Chernykh at the Crimean Astrophysical Observatory in Nauchnij, on the Crimean peninsula. The likely elongated S-type asteroid has a rotation period of 5.44 hours. It was named for the Russian village of Borodino where the Battle of Borodino took place.
4007 Euryalos is a larger Jupiter trojan from the Greek camp, approximately 48 kilometers in diameter. It was discovered on 19 September 1973, by Dutch astronomers Ingrid and Cornelis van Houten at Leiden, and Tom Gehrels at Palomar Observatory in California. The likely spherical Jovian asteroid is the principal body of the proposed Euryalos family and has a rotation period of 6.4 hours. It was named after the warrior Euryalus from Greek mythology.
4754 Panthoos is a Jupiter trojan from the Trojan camp, approximately 53 kilometers in diameter. It was discovered during the third Palomar–Leiden Trojan survey on 16 October 1977, by Ingrid and Cornelis van Houten at Leiden, and Tom Gehrels at the Palomar Observatory in California. It is likely spherical in shape and has a longer-than-average rotation period of 27.68 hours. The assumed C-type asteroid is one of the 80 largest Jupiter trojans. It was named after Panthous (Panthoos) from Greek mythology.
Hitomi, also known as ASTRO-H and New X-ray Telescope (NeXT), was an X-ray astronomy satellite commissioned by the Japan Aerospace Exploration Agency (JAXA) for studying extremely energetic processes in the Universe. The space observatory was designed to extend the research conducted by the Advanced Satellite for Cosmology and Astrophysics (ASCA) by investigating the hard X-ray band above 10 keV. The satellite was originally called New X-ray Telescope; at the time of launch it was called ASTRO-H. After it was placed in orbit and its solar panels deployed, it was renamed Hitomi. The spacecraft was launched on 17 February 2016 and contact was lost on 26 March 2016, due to multiple incidents with the attitude control system leading to an uncontrolled spin rate and breakup of structurally weak elements.
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