As the first geostationary satellite developed in Korea, Cheollian 1 observes the weather and oceans around the Korean Peninsula and provides satellite communication test services. Cheollian 1 was developed to have the capability to build geostationary satellites in Korea and secure mid-sized geostationary satellite technology. Although Korea had acquired the know-how to develop the Arirang satellite, a low Earth orbit satellite, it had none on developing geostationary satellites. Cheollian 1 was designed and assembled in collaboration with Astrium, an overseas partner. KARI acquired geostationary satellite development technology through the development of Cheollian 1 and independently designed and developed the subsequent satellites, Cheollian 2A and 2B.
With the launch of Cheollian 1, Korea became the world’s seventh country to have a meteorological observation satellite after the United States, Europe, Japan, China, India, and Russia. Until then, Korea had received meteorological data from overseas satellites, but the launch of Cheollian 1 enabled obtaining weather observation data generated by its satellite. Cheollian 1 is the first geostationary satellite developed by Korea, and it is performing various missions. As the first meteorological satellite, it is contributing to the improvement of people's living standards by providing weather forecasts reflecting rapidly changing meteorological information.
Cheollian 1 can observe the weather every 15 minutes during normal times and every 8 minutes during extreme weather events such as typhoons. It has performed meteorological missions such as the continuous generation of high-resolution multi-channel meteorological images, calculation of meteorological factors, early detection of unusual meteorological phenomena such as typhoon, concentrated heavy rain, yellow sand, and sea fog, and calculation of long-term sea surface temperature and cloud data. The payload for meteorological missions has a total of five channels: one visible band (resolution 1 km) and four IR band channels (4 km resolution). It can observe the globe, Asia-Pacific region, and Korean Peninsula constantly.
Moreover, Cheollian 1 is the world's first satellite to observe the ocean from the geostationary orbit, monitoring the marine environment around the Korean Peninsula in real time. Marine observation missions include monitoring the marine environment and marine ecology around the Korean Peninsula, estimating marine chlorophyll production, and producing fishery information. The marine payload has eight channels in the visible and near-IR bands, and it can observe a 2,500 ㎞ x 2,500 ㎞ area around the Korean Peninsula at 1-hour intervals during daytime.
Developing Cheollian 1, the world's tenth communication satellite, laid the foundation for the next-generation satellite information and communication system to provide satellite communication, broadcasting, geographic, and traffic information. The communication payload is used for test broadcasting to develop high-resolution video transmission technology and verify public disaster communication functions and methods of resolving poor TV reception. Communication missions include broadband satellite multimedia testing service, domestic communication payload space certification, and geostationary satellite control system localization. The communication payload consists of two reflector antennas with a diameter of 1.1 m and 3 Ka-band communication repeater channels(1 spare channel). It provided test communication and broadcasting services in the geostationary orbit for space certification of the communication payloads developed in Korea.
Cheollian 1 completed its meteorological observation mission in April 2020, and the marine payload mission is expected to end in 2021.