EO 1

EO 1 is an active satellite operated by United States, launched on 2000-11-21 from Vandenberg SFB, California. With over 26 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 656 km and 671 km with an inclination of 98.1°. It travels at approximately 27,099 km/h (7.53 km/s), completing one full orbit every 98 minutes — that’s roughly 14.69 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. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~10–25 years. Orbital Radar tracks EO 1 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

EO 1 orbits at an average altitude of 664 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 EO 1’s average altitude, there are currently 644 active payloads and 1,129 tracked debris or rocket body fragments — notable neighbours include TERRA, AQUA, LANDSAT 9. With an inclination of 98.1°, EO 1 passes over latitudes between 98.1°N and 98.1°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. United States operates approximately 12,360 active satellites in total, of which 280 share a similar altitude band with EO 1.