Miris: A compact wide–field infrared space telescope

A compact infrared space telescope called MIRIS (Multi-purpose Infra-Red Imaging System) was developed by the Korea Astronomy and Space Science Institute (KASI), and launched onboard the Science and Technology Satellite-3 of Korea (STSAT-3) in 2013 November. The main mission of MIRIS is the Paschen-α emission line survey along the Galactic plane and the cosmic infrared background (CIB) observation, particularly around the north ecliptic pole region. For these missions, a wide field of view (3:67 × 3:67°) with an angular resolution of 51.6″ and wavelength coverage from 0:9 ∼ 2:0 μm have been adopted for MIRIS, having optical components consisting of a 80 mm main lens and four other lenses with F/2 focal ratio optics. The opto-mechanical system was carefully designed to minimize any effects from shock during the launch process and thermal variation. Also, the telescope was designed to use a passive cooling technique to maintain the temperature around 200 K in order to reduce thermal noise. A micro Stirling cooler was used to cool down the Teledyne PICNIC infrared array to 90 K, which was equipped in a dewar with four filters for infrared passbands of I, H, and Paschen-α and a dual-band continuum line filter. MIRIS system was integrated into the STSAT-3 as its primary payload and successfully passed required tests in the laboratory, such as thermal-vacuum, vibration, and shock tests. MIRIS is now operating in sun synchronous orbits for initial tests and has observed its first images successfully.