KOMPSAT-3

KOMPSAT-3 (Korean Multi-purpose Satellite-3), also known as Arirang-3, is a South Korean multipurpose Earth observation satellite. It was launched from Tanegashima Space Center, Japan at 16:39 UTC on 17 May 2012. Like the earlier KOMPSAT-1 and KOMPSAT-2 satellites, it takes its name from the popular Korean folk song Arirang. Its launch was the culmination of a project begun in 1995.

KOMPSAT-3 orbits at a height of 685.1 km, circling the Earth 14 times per day, and is expected to maintain that orbit for 4 years. It weighs 980 kg. The satellite carries an Advanced Earth Imaging Sensor System (AEISS), which can distinguish to a 70-cm resolution, allowing the identification of individual vehicles on the ground.

The satellite was succeeded by KOMPSAT-5 and KOMPSAT-3A, which were launched on 2013 and 2015 respectively.

History
South Korea started the KOMPSAT programme in 1995 to nurture its national Earth-imaging industry and supply services for remote-sensing applications. The South Korean KOMPSAT-3 Earth-imaging satellite was developed by Korea Aerospace Industries (KAI) and Korea Aerospace Research Institute (KARI), in partnership with EADS Astrium, to assure continuity with the KOMPSAT-2 satellite launched in 2006. KOMPSAT-3 was orbited on 17 May 2012 by a launch vehicle from Tanegashima Space Center, Japan. SI Imaging Services is the worldwide exclusive distributor of KOMPSAT imagery since November 2012.

Orbit
KOMPSAT-3 operates in a near-polar, circular Sun-synchronous orbit. The orbital parameters are:
 * Mean altitude: 685.1 km
 * Mass: 980 kg
 * Inclination: 98.13° (Sun-synchronous orbit)
 * Orbital period: 98.5 minutes
 * Orbital cycle: 28 days

Instruments
KOMPSAT-3's instruments are designed to acquire high- and very-high-resolution imagery with a footprint of 16.8 km. The satellite has the capacity to acquire 20 minutes of imagery on each orbit and it can steer its sensors both ways out to 30° off track. Panchromatic and multispectral images can be acquired at the same time.

KOMPSAT-3 radiometer features:

Ground receiving stations
Two receiving stations deliver KOMPSAT-3 imagery 1 to 3 days after acquisition. The Deajeon station in South Korea is responsible for tasking the satellite.

Advantages and applications of KOMPSAT-3 imagery
KOMPSAT-3 is designed for very-high-resolution (VHR) remote-sensing applications, such as:
 * Land planning: to detect and identify features smaller than 1 square meter, e.g. vehicles, street furnishings, roads and bushes
 * Agriculture: to pinpoint crop or tree diseases
 * Urban planning and demographics: to locate detached houses
 * Civil engineering: to plan road, railroad and oil pipeline corridors
 * Defence: to describe high-value assets or military sites

South Korea
It serves along with the existing Kompsat-2 to provide continuous satellite observation of the Korean Peninsula, sending images twice a day at 01:30 and 13:30.