OBSERVER-1A

OBSERVER-1A is an active satellite operated by South Korea, launched on 2023-11-11 from Vandenberg SFB, California. It orbits in Low Earth Orbit (LEO) at altitudes between 444 km and 456 km with an inclination of 97.4°. It travels at approximately 27,520 km/h (7.64 km/s), completing one full orbit every 94 minutes — that’s roughly 15.39 orbits per day. Its near-polar, sun-synchronous orbit means it passes over any given point on Earth at approximately the same local solar time, ideal for consistent Earth observation lighting conditions. Its near-circular orbit (eccentricity close to zero) means it maintains a very consistent altitude throughout each revolution. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~1–3 years. Orbital Radar tracks OBSERVER-1A in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

OBSERVER-1A orbits at an average altitude of 450 km in a sun-synchronous orbit (SSO), a specialised subset of LEO where the orbital plane precesses to maintain a constant angle relative to the Sun. This provides consistent lighting conditions on every pass — essential for Earth observation, weather monitoring and environmental science. Within ±50 km of OBSERVER-1A’s average altitude, there are currently 7,715 active payloads and 165 tracked debris or rocket body fragments — notable neighbours include STARLINK-1008, STARLINK-1012, STARLINK-1017. This makes it one of the more crowded altitude bands, containing roughly 44.3% of all active satellites. With an inclination of 97.4°, OBSERVER-1A passes over latitudes between 97.4°N and 97.4°S, providing near-global coverage including the polar regions. Polar and near-polar orbits are used for reconnaissance, weather monitoring and Earth-observation missions that need to image every part of the planet. South Korea operates approximately 51 active satellites in total, of which 9 share a similar altitude band with OBSERVER-1A.