AKARI (ASTRO-F) was an

infrared astronomy Infrared astronomy is a sub-discipline of astronomy which specializes in the astronomical observation, observation and analysis of astronomical objects using infrared (IR) radiation. The wavelength of infrared light ranges from 0.75 to 300 microm ...

satellite A satellite or an artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation ( GPS), broadcasting, scient ...

developed by

Japan Aerospace Exploration Agency The is the Japanese national Aeronautics, air and space agency. Through the merger of three previously independent organizations, JAXA was formed on 1 October 2003. JAXA is responsible for research, technology development and launch of satell ...

, in cooperation with institutes of Europe and Korea. It was launched on 21 February 2006, at 21:28

UTC Coordinated Universal Time (UTC) is the primary time standard globally used to regulate clocks and time. It establishes a reference for the current time, forming the basis for civil time and time zones. UTC facilitates international communica ...

(06:28, 22 February JST) by

M-V rocket The M-V rocket, also called M-5 or Mu-5, was a Japanese solid-fuel rocket designed to launch scientific satellites. It was a member of the Mu family of rockets. The Institute of Space and Astronautical Science (ISAS) began developing the M-V i ...

into Earth

Sun-synchronous orbit A Sun-synchronous orbit (SSO), also called a heliosynchronous orbit, is a nearly polar orbit around a planet, in which the satellite passes over any given point of the planet's surface at the same local mean solar time. More technically, it is ...

. 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 Far infrared (FIR) or long wave refers to a specific range within the infrared spectrum of electromagnetic radiation. It encompasses radiation with wavelengths ranging from 15 μm ( micrometers) to 1 mm, which corresponds to a freque ...

, through its aperture telescope.

Technical design

Its designed lifespan, of far- and mid-infrared sensors, was 550 days, limited by its liquid

helium Helium (from ) is a chemical element; it has chemical symbol, symbol He and atomic number 2. It is a colorless, odorless, non-toxic, inert gas, inert, monatomic gas and the first in the noble gas group in the periodic table. Its boiling point is ...

coolant. Its telescope mirror was made of

silicon carbide Silicon carbide (SiC), also known as carborundum (), is a hard chemical compound containing silicon and carbon. A wide bandgap semiconductor, it occurs in nature as the extremely rare mineral moissanite, but has been mass-produced as a powder a ...

to save weight. The budget for the satellite was ¥13,4 billion (~).

History

By mid-August 2006, AKARI finished around 50 per cent 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 A Sun sensor is a navigational instrument used by spacecraft to detect the position of the Sun. Sun sensors are used for Spacecraft attitude control, attitude control, solar array pointing, gyroscope, gyro updating, and safe mode (spacecraft), fai ...

after the launch, ejection of telescope

aperture In optics, the aperture of an optical system (including a system consisting of a single lens) is the hole or opening that primarily limits light propagated through the system. More specifically, the entrance pupil as the front side image o ...

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. On 11 July 2007, JAXA informed that 90 per cent 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. More than 96 per cent 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 This Daiwa Adrian Prize is an award given by The Daiwa Anglo-Japanese Foundation, a UK charity, to scientists who have made significant achievements in science through Anglo-Japanese collaborative research. Prizes are awarded every third year and ...

in 2004, by the

Daiwa Anglo-Japanese Foundation The Daiwa Anglo-Japanese Foundation () is a United Kingdom-based charity (registered no. 299955) established in 1988 to support closer links between Britain and Japan. It was founded with a benefaction from Daiwa Securities Co Ltd (now known as ...

in recognition of their collaboration. During December 2007, JAXA performed orbit correction manoeuvres to bring AKARI back into its ideal orbit. This was necessary because the boiled off

led to an increase in altitude. If this had continued, the energy supply would have been cut off.

2008–2010

A limited observation 'warm' programme continued with just NIR.

End of mission

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. The operation of satellite was terminated officially on 24 November 2011. The satellite reentered the atmosphere on 11 April 2023 at 04:44 UTC.

Results

*Star formation over three generations in the

nebula A nebula (; or nebulas) is a distinct luminescent part of interstellar medium, which can consist of ionized, neutral, or molecular hydrogen and also cosmic dust. Nebulae are often star-forming regions, such as in the Pillars of Creation in ...

IC4954/4955 in the constellation

Vulpecula Vulpecula is a faint constellation in the northern sky. Its name is Latin for "little fox", although it is commonly known simply as the fox. It was identified in the seventeenth century, and is located in the middle of the Summer Triangle (an ...

. *The first infrared detection of a supernova remnant in the

Small Magellanic Cloud The Small Magellanic Cloud (SMC) is a dwarf galaxy near the Milky Way. Classified as a dwarf irregular galaxy, the SMC has a D25 isophotal diameter of about , and contains several hundred million stars. It has a total mass of approximately 7 bill ...

*Detection of mass-loss from relatively young red-giant stars in the

globular cluster A globular cluster is a spheroidal conglomeration of stars that is bound together by gravity, with a higher concentration of stars towards its center. It can contain anywhere from tens of thousands to many millions of member stars, all orbiting ...

NGC 104 47 Tucanae or 47 Tuc (also designated as NGC 104 and Caldwell 106) is a globular cluster located in the constellation Tucana. It is about from Earth, and 120 light years in diameter. 47 Tuc can be seen with the naked eye, with an apparent magnit ...

*Detection of the molecular gas surrounding the

active galactic nucleus An active galactic nucleus (AGN) is a compact region at the center of a galaxy that emits a significant amount of energy across the electromagnetic spectrum, with characteristics indicating that this luminosity is not produced by the stars. Such e ...

in the ultra

luminous infrared galaxy Luminous infrared galaxies or LIRGs are galaxies with luminosities, the measurement of brightness, above . They are also referred to as submillimeter galaxies (SMGs) through their normal method of detection. LIRGs are more abundant than starburst ...

*The constellation Orion and the winter

Milky Way The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galax ...

at 140

micrometre The micrometre (English in the Commonwealth of Nations, Commonwealth English as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American English), also commonly known by the non-SI term micron, is a uni ...

*Star forming region in the constellation Cygnus *Active star formation viewed from the outside: The peculiar spiral galaxy M101 *Dust processing in the

supernova A supernova (: supernovae or supernovas) is a powerful and luminous explosion of a star. A supernova occurs during the last stellar evolution, evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion ...

remnants in the

Large Magellanic Cloud The Large Magellanic Cloud (LMC) is a dwarf galaxy and satellite galaxy of the Milky Way. At a distance of around , the LMC is the second- or third-closest galaxy to the Milky Way, after the Sagittarius Dwarf Spheroidal Galaxy, Sagittarius Dwarf ...

The AKARI All-Sky Survey Point Source Catalogues was released on 30 March 2010.

Astronomy and Astrophysics ''Astronomy & Astrophysics (A&A)'' is a monthly peer-reviewed scientific journal covering theoretical, observational, and instrumental astronomy and astrophysics. It is operated by an editorial team under the supervision of a board of directors re ...

, Vol. 514 (May 2010) was a feature issue of AKARI's results.

References

External links

JAXA/ISAS AKARI mission information
{{Portal bar, Astronomy, Stars, Spaceflight, Outer space, Solar System Spacecraft launched in 2006 Spacecraft which reentered in 2023 Infrared telescopes Satellites of Japan Space telescopes