ASTRO-F: Infrared imaging surveyor (IRIS) mission

The Infrared Imaging Surveyor (IRIS) is the second infrared satellite mission of the Institute of Space and Astronautical Science (ISAS), japan. It is scheduled to be launched in the middle of 2003 with the M-V rocket of ISAS. It has a 70-cm aperture telescope of SiC mirrors and is cooled to 6 K with Stirling-cycle coolers and 170 liters of liquid helium. It is planned as a second generation infrared sky survey mission. Two scientific instruments share the focal plane. The infrared camera (IRC) covers the 2 to 26 mum range with large 2-dimensional arrays in the imaging and low-resolution spectroscopic modes. The IRC will perform deep sky surveys of selected areas of the sky with a wide field of view (10' x 10') at unprecedented sensitivity, at least 10 times deeper than ISOCAM, and will also provide low-resolution spectra of a large number of objects. The far-infrared Surveyor (FIS) covers the 50 to 200 mum range, consisting of an imaging scanner and a Fourier transform spectrometer. The FIS will make a whole sky survey in four far-infrared bands, which is higher by more than 10 in sensitivity (20 - 110 mJy), better by several in the spatial resolution (30 " - 50 "), and longer in the spectral coverage (200 mum) than the IRAS survey. IRIS will provide a significant data base for future observatory-type missions, such as SIRTF, SOFIA, FIRST, NGST, and HII/L2. A brief description of the IRIS mission is presented.