KOMPSAT-3A

KOMPSAT-3A, also known by its Korean name Arirang-3A, is a South Korean Earth observation satellite operated by the Korea Aerospace Research Institute (KARI). Assigned NORAD catalog ID 40536 and international designator 2015-014A, the spacecraft was launched in March 2015 and continues to orbit Earth as of the time of writing. It represents a significant step in South Korea's ongoing development of domestic space-based remote sensing capabilities, combining high-resolution optical imaging with an infrared sensing capability in a single platform.

Mission and Purpose

The primary mission of KOMPSAT-3A is Earth observation, providing imagery useful for a broad range of civil, scientific, and governmental applications. These typically include land-use monitoring, agricultural assessment, disaster response, environmental surveillance, and cartographic mapping. Such missions rely on the ability to capture detailed imagery across multiple spectral bands, and KOMPSAT-3A addresses this need by carrying both a sub-meter-resolution electro-optical camera, capable of resolving ground features at approximately 55 centimeters, and a dedicated infrared sensor.

The infrared imaging capability meaningfully expands the satellite's operational envelope beyond what visible-light cameras alone can offer. Thermal infrared sensors can detect heat signatures on the Earth's surface, enabling applications such as monitoring of industrial activity, identification of heat anomalies associated with natural disasters or wildfires, and nighttime imaging in conditions where optical systems would otherwise be limited. Together, these two instruments allow KOMPSAT-3A to collect data across a wider range of environmental and operational conditions than its predecessor, KOMPSAT-3, which carried only electro-optical instrumentation.

KOMPSAT-3A was developed entirely within South Korea under the stewardship of KARI, reflecting the country's broader policy objective of achieving self-reliance in critical space technologies. The program builds on a lineage of KOMPSAT satellites—short for Korea Multi-Purpose Satellite—that stretches back to the late 1990s, with each successive generation bringing higher resolution, expanded spectral capability, or improved revisit times. KOMPSAT-3A sits within this developmental arc as one of the program's more capable optical reconnaissance and observation platforms.

The manufacturer of the spacecraft is not recorded in publicly available catalog data. KARI has historically collaborated with international aerospace firms on various KOMPSAT platforms while simultaneously working to increase the domestic content of subsequent satellites, but specific manufacturing details for KOMPSAT-3A are not confirmed in this entry.

Orbit and Tracking

KOMPSAT-3A operates in a sun-synchronous orbit (SSO), a specific class of near-polar, low Earth orbit in which the orbital plane precesses at a rate that keeps it approximately aligned with the Sun-Earth geometry throughout the year. This configuration ensures that the satellite passes over any given location on the ground at a consistent local solar time on each revisit, which is highly advantageous for Earth observation missions. By maintaining roughly constant illumination conditions across successive passes, a sun-synchronous orbit facilitates reliable comparison of imagery taken at different times—an essential property for change-detection applications such as monitoring deforestation, urban expansion, or flood extent.

The current orbital parameters place KOMPSAT-3A at an apogee of 448 km and a perigee of 372 km, giving the orbit a mild eccentricity. The orbital inclination is 97.7°, which is slightly retrograde with respect to Earth's rotation—a characteristic common to sun-synchronous orbits, which require an inclination somewhat greater than 90° to achieve the necessary nodal precession rate. The satellite completes one full orbit approximately every 92.6 minutes, meaning it circles the Earth roughly 15 to 16 times per day.

At these altitudes, KOMPSAT-3A operates within a regime of low Earth orbit that, while broadly stable over medium timescales, is subject to gradual orbital decay caused by residual atmospheric drag. The difference between apogee and perigee—roughly 76 km—is within the normal range for operational LEO payloads and reflects the satellite's orbital history since launch. Despite this, KOMPSAT-3A remains in orbit and continues to be tracked by the U.S. Space Surveillance Network, which maintains its catalog entry under NORAD ID 40536.

The inclination and altitude together determine the satellite's ground track and revisit characteristics. For a high-resolution imager at roughly 400–450 km altitude, the swath width of the imaging sensor and the orbital geometry govern how frequently any given point on Earth can be observed. Users of imagery from sun-synchronous platforms at this altitude typically expect revisit periods on the order of days for mid-latitude locations, depending on off-nadir pointing capability.

Design and Operator

KOMPSAT-3A was developed and is operated by the Korea Aerospace Research Institute, the principal government body responsible for space research and satellite development in South Korea. KARI was established in the 1980s and has progressively grown into a comprehensive space agency responsible for launch vehicle development, satellite design, and mission operations. The KOMPSAT series of satellites has been one of the institute's flagship programs, providing South Korea with a sovereign remote sensing capability that reduces its dependence on foreign sources for satellite imagery.

The satellite was launched on March 25, 2015. It was carried to orbit by a Russian Dnepr rocket from the Dombarovsky launch site in Russia, a launch vehicle frequently used during that period for multi-payload commercial and governmental missions. Following separation and orbit insertion, KOMPSAT-3A was checked out and transitioned to routine operations.

The spacecraft's mass is not publicly confirmed in the available catalog data. Its design, as with many Earth observation satellites of its generation and capability class, would be expected to incorporate attitude control systems sufficient to support precision pointing for sub-meter imaging, onboard data storage for imagery acquired during passes over areas outside ground station contact, and encrypted or secure downlink protocols appropriate for a government-operated observation platform. However, these specifics are not verified in the source catalog and are noted here only as general context for the class of satellite.

KOMPSAT-3A carries a multi-spectral electro-optical camera providing approximately 55 cm ground resolution, placing it firmly in the high-resolution category for governmental Earth observation satellites at the time of its launch. The addition of an infrared imaging channel distinguished it from its direct predecessor and aligned South Korea's remote sensing portfolio more closely with the capabilities of leading international platforms.

Significance and Current Status

The launch and successful operation of KOMPSAT-3A marked an important milestone in the maturation of South Korea's space program. Achieving sub-meter resolution from a domestically managed satellite program placed South Korea among a relatively small group of nations operating sovereign high-resolution imaging satellites—a capability with both civilian and strategic dimensions. For civilian purposes, sub-meter imagery supports precise land management, infrastructure monitoring, and emergency response coordination. The strategic dimensions of such a capability are widely recognized in the international remote sensing community, as imagery of this quality can support a range of national security assessments.

The satellite's inclusion of an infrared sensor further broadened its utility, offering a capacity that is particularly valuable for monitoring the Korean Peninsula's complex environmental and geopolitical landscape, as well as supporting broader regional and global observation needs.

As of the time of writing, KOMPSAT-3A remains in orbit and is presumed to be operational or at least tracked as an active payload, though specific mission status information is not confirmed in the catalog data referenced by this entry. Its continuation in orbit after a decade since launch is notable, as many satellites of this class are designed for operational lifetimes in the range of several years, and longevity depends on factors including fuel reserves for station-keeping, instrument health, and ground segment support.

The KOMPSAT program has continued to evolve since KOMPSAT-3A's launch, with subsequent satellites building on the technological foundation it helped establish. Within the broader context of South Korea's space ambitions—which now encompass indigenous launch vehicles and lunar exploration plans—KOMPSAT-3A stands as one of the program's more capable mid-generation platforms.

How to Spot It

KOMPSAT-3A orbits at a relatively low altitude, between roughly 372 and 448 km above Earth's surface, which places it well within the range at which Earth observation satellites can occasionally be seen with the naked eye under favorable conditions. However, its visibility to ground observers depends heavily on its size, surface reflectivity, and orientation at the time of a given pass—none of which are confirmed in the catalog data for this entry.

As with most low Earth orbit payloads, KOMPSAT-3A will be most visible during twilight hours, when the observer is in darkness but the satellite is still illuminated by sunlight. Passes near sunrise or sunset, when the satellite is high enough in the sky to catch direct sunlight while the ground below is shadowed, offer the best viewing windows. Dedicated satellite-tracking tools, including the real-time tracking features available on this site using NORAD ID 40536, provide precise pass predictions for any given observer location and are the recommended means of planning an observation attempt.