SPICA: A 3.5Â m space infrared telescope for mid- and far-infrared astronomy

The Space Infrared Telescope for Cosmology and Astrophysics (SPICA) mission is a Japanese astronomical infrared satellite project optimized for mid- to far-infrared observations. It will be launched at ambient temperature and cooled down on orbit by mechanical coolers on board with an efficient radiative cooling system, a combination of which allows us to have a 3.5-m class cooled (4.5 K) telescope in space. SPICA will give us deep insights into a number of key problems in present-day astronomy, ranging from the star-formation history of the universe to the formation of planets, owing to its high spatial resolution and unprecedented sensitivity in the mid- to far-infrared. We have made successful progress in the development of mechanical coolers, whereas silicon carbide and carbon-fiber reinforced silicon carbide have been extensively investigated as primary candidates for the SPICA telescope mirrors. We present the current status of the SPICA project as well as the results of technology developments.