Astro-F (Akari)

Launch data: Designation  28939 / 06005A Launch date  21 Feb 2006 - 21:28 UT Launch site  Uchinoura Launch vehicle  M-5 (2) Mission  Government: Scientific Research Astronomy Sun-Synchronous LEO Earth orbit on: Perigee / Apogee  707 x 716 km Eccentricity  6.35E-04 Inclination  98.2° Period  99.2 min

Description:

ASTRO-F, originally named IRIS (InfraRed Imaging Surveyor), is a 70 cm cooled telescope. It has a much more powerful capability for survey work than the IRAS, owing to the advanced technologies now available:

• ASTRO-F covers wide wavelength range from K-band to 200 µm. ASTRO-F will perform an all-sky survey at wavelengths > 50 µm using high-sensitivity Ge:Ga detector arrays. In the near- and mid-infrared ranges, large-format arrays are employed for a deep sky survey in selected sky regions.
• The sensitivity of ASTRO-F is much higher than that of the IRAS. For example, the ASTRO-F has 50-100 times higher sensitivity at 100 µm and more than 1000 times at mid-infrared wavelengths.
• ASTRO-F has a diffraction-limited angular resolution at wavelengths longer than 10 µm. The pixel sizes of ASTRO-F are less than 1 arcmin even at 100-200 µm, several times smaller than the beam of the IRAS.
• ASTRO-F has capabilities for low-resolution spectroscopy. In the near- and mid-infrared ranges, spectroscopy using prisms is available. The Fourier-transform spectrometer is used for the wavelength range from 50 to 200 µm. This capability is very important for classification of sources detected in the deep survey, rough determination of the redshift, etc.

Mission details:

• Japan launched the ASTRO-F infrared astronomy satellite at 21:28 UTC on Feb 21. ASTRO-F separated from the M-V-8 rocket final stage in a 301 x 718 km x 98.2 deg orbit; it will use an onboard propulsion system to reach its final orbit and then will eject its optics cover. The satellite has been named "Akari" (light). By Mar 3 it was in a 707 x 716 km x 98.2 deg orbit; this had been adjusted to 695 x 710 km by Mar 16. Because of attitude control problems, ejection of the optics cover has been delayed until mid-April.
• Akari carries a 0.67m-diameter liquid-helium-cooled infrared telescope with detectors ranging from the near infrared to 60 and 170 micron channels in the far IR. It will carry out the first far infrared sky survey since IRAS in 1983.