COMS 1

COMS 1, internationally designated 2010-032A and carrying NORAD catalog ID 36744, is a South Korean multipurpose satellite operating in geostationary orbit. Better known by its Korean name Chollian, the spacecraft was launched on June 25, 2010 and entered operational service the following year, becoming one of South Korea's most capable and versatile orbital assets. Designed to serve simultaneously as a communications relay, an ocean color imager, and a meteorological observer, Chollian represented a significant milestone in South Korea's development of homegrown satellite infrastructure. As of the time of writing, the spacecraft remains in orbit.

Mission and Purpose

Chollian — whose name evokes the Korean concept of vast or boundless sky — was conceived as a three-in-one platform, combining capabilities that are often spread across separate satellites in other national programs. The Korea Aerospace Research Institute (KARI) operated the satellite in service of three distinct but complementary objectives.

The first and perhaps most publicly visible function was meteorological monitoring. Geostationary weather satellites occupy a uniquely valuable role in atmospheric science: because they hover over a fixed point on Earth's surface, they can image the same region continuously rather than making periodic passes like low-orbiting craft. This allows them to track the development of storms, typhoons, and weather fronts in near real time, providing data essential for forecasting services. Chollian's meteorological instrument gave South Korea and the broader Northeast Asian region an additional source of such continuous coverage, complementing international networks of weather satellites that had long been operated by agencies such as NOAA, EUMETSAT, and the Japan Meteorological Agency.

The second mission area was oceanographic observation. The satellite carried an ocean color instrument capable of monitoring sea surface conditions, phytoplankton concentrations, sediment distribution, and related parameters across the waters surrounding the Korean Peninsula and beyond. Ocean color imaging from geostationary altitude is relatively uncommon, as most dedicated ocean observation platforms use lower, sun-synchronous orbits to achieve higher resolution. Operating from geostationary altitude, however, offers the compensating advantage of high temporal frequency — the ability to observe the same patch of ocean many times per day — which is particularly useful for tracking dynamic, fast-changing phenomena like algal blooms or sediment plumes from river outflows.

The third function was communications. While the publicly available catalog record does not specify the nature or extent of the communications payload in detail, a communications capability was part of Chollian's stated multi-mission design from the outset. The satellite's position in geostationary orbit made it inherently well-suited to serve as a relay platform for fixed and potentially mobile users within its coverage footprint.

Operations are understood to have begun on April 1, 2011, roughly nine months after launch — a timeline consistent with the in-orbit testing, calibration, and commissioning procedures that complex multipurpose satellites typically require before they are declared operational.

Orbit and Tracking

COMS 1 occupies a geostationary orbit, one of the most strategically and operationally important orbital regimes in use today. Geostationary orbit lies roughly 35,786 kilometers above the equator — the precise altitude at which an object's orbital period matches Earth's rotation period of approximately 24 hours — causing the satellite to appear stationary relative to observers on the ground. This property is what makes geostationary orbit so valuable for communications and continuous Earth observation.

The tracked orbital parameters for COMS 1 confirm this classification. Its apogee stands at 35,799 km and its perigee at 35,791 km, reflecting an orbit that is nearly perfectly circular and located squarely within the geostationary band. The orbital period is 1,436.2 minutes — just over 23 hours and 56 minutes, which corresponds closely to one sidereal day, the period used to define the geostationary condition. The slight difference from a calendar day arises from the distinction between sidereal and solar time, and is standard for all geostationary objects.

One notable parameter is the satellite's orbital inclination of 4.8°. A perfectly maintained geostationary satellite has an inclination of 0°, meaning its orbit lies exactly in the equatorial plane. As satellites age and active station-keeping maneuvers are reduced or ceased to conserve fuel, gravitational perturbations from the Moon and Sun cause the inclination to drift upward over time. An inclination of 4.8° suggests either that some degree of inclination drift has occurred since launch, that active north-south station-keeping is no longer being performed at full capacity, or some combination of these factors. From the ground, an inclined geostationary orbit causes the satellite to trace a small figure-eight or analemma-like path in the sky over the course of a day rather than remaining at a truly fixed point — a motion that ground antennas with sufficiently narrow beamwidths must compensate for. The current operational status of the satellite is not confirmed in the publicly available catalog record.

Design and Operator

COMS 1 has a launch mass of 2,460 kg, placing it in the medium-to-large class of geostationary communications and observation satellites. The identity of the spacecraft's manufacturer is not recorded in the publicly available catalog data for this entry.

The satellite was operated by the Korea Aerospace Research Institute, the principal government agency responsible for aerospace research, satellite development, and space launch activities in South Korea. KARI, established in the late 1980s, has been the driving force behind South Korea's progressive development of satellite technology, from early remote sensing spacecraft to more ambitious platforms like Chollian. The institute's role as operator of COMS 1 placed it in charge not only of the platform's day-to-day health and station-keeping but also of coordinating the use of its scientific and communications payloads with relevant downstream users — including meteorological services and oceanographic research communities.

The satellite was launched on June 25, 2010, at 8:00 PM Eastern Daylight Time, corresponding to the early hours of June 26 in Korean Standard Time, which accounts for the date sometimes cited as June 26 in Korea-centric reporting. Geostationary satellites of this class are typically delivered to a geostationary transfer orbit by the launch vehicle before firing their own apogee engine to raise the perigee and circularize the orbit at geostationary altitude — a process that can take several weeks and consumes a substantial portion of the onboard propellant budget. The remaining propellant is then available for station-keeping throughout the satellite's operational life.

Significance and Current Status

Chollian holds a meaningful place in the history of South Korean space development. Before its launch, South Korea relied on foreign-operated satellites and international data-sharing arrangements to meet its meteorological and oceanographic satellite data needs. The deployment of a domestically operated, multipurpose geostationary satellite marked a step toward greater national self-sufficiency in space-based Earth observation — particularly valuable for a country with extensive coastlines, a complex maritime environment, and a geographic position in a region prone to significant weather events including typhoons and heavy seasonal precipitation.

The three-in-one architecture of the satellite also demonstrated an approach to maximizing return on the considerable investment required to develop, launch, and operate a geostationary platform. By combining meteorological, oceanographic, and communications capabilities on a single bus, the program could spread costs across multiple user communities and government agencies.

South Korea subsequently developed and launched follow-on satellites building on the experience gained from Chollian, including more advanced geostationary Earth observation and meteorological platforms. In this respect, COMS 1 can be understood not only as an operational asset in its own right but as a stepping stone in a longer national program.

As of the most recent catalog data available to this site, COMS 1 remains in orbit and has not undergone atmospheric reentry. Its inclination of 4.8° is consistent with a satellite that may be in a reduced station-keeping or end-of-life phase, though the current mission status is not confirmed in the public record. Geostationary satellites that have exhausted their station-keeping propellant are typically commanded to a slightly higher "graveyard" orbit above the geostationary belt, where they pose no interference risk to active operational satellites. Whether COMS 1 has been or will be disposed of in this manner is not reflected in the data currently available through this catalog.

How to Observe COMS 1

As a geostationary satellite, COMS 1 does not move across the sky in the way that low Earth orbit satellites do, and it is not visible to the naked eye under ordinary circumstances. Its apparent stationary position makes it undetectable without optical aid for casual observers. However, amateur astronomers and satellite observers equipped with telescopes and precise pointing information can in principle locate geostationary satellites as faint, slow-moving or apparently stationary points of light against the star field. The satellite's inclination of 4.8° means that its apparent sky position traces a slow daily figure-eight, which advanced observers may be able to track. Real-time positioning data for COMS 1 is available through this site's tracking tools.