The primary payload of STSAT-3 (Science and Technology Satellite 3), 
MIRIS (Multipurpose InfraRed Imaging System), is the first Korean 
infrared space mission to explore the near-infrared sky with a compact 
near-infrared camera. It was successfully launched in last November. The 
8-cm passively cooled telescope with a wide field of view (3.67 deg. x 3.
67 deg.) operates in the wavelength range from 0.9 to 2 um. After the 
performance verification during 3 months, it is performing two large 
area surveys: 10 deg. x 10 deg. survey of the north ecliptic pole (NEP) 
at I and H bands and Pa-alpha survey of the Galactic plane. The NEP 
survey enables us to reveal the nature of degree-scale sky fluctuation 
and to measure the absolute brightness of cosmic infrared background 
(CIB). The Paschen-alpha emission line survey of Galactic plane helps us 
to understand the origin of Warm Ionized Medium (WIM) and to find the 
physical properties of interstellar turbulence.