OAO 1

OAO 1 is an active satellite operated by GSFC (United States), launched on 1966-04-08 from Cape Canaveral Space Force Station, United States on the OAO A1 launch. After more than 60 years in orbit, it is one of the longest-surviving objects in the space catalogue. It orbits in Low Earth Orbit (LEO) at altitudes between 771 km and 781 km with an inclination of 35.0°. It travels at approximately 26,885 km/h (7.47 km/s), completing one full orbit every 100 minutes — that’s roughly 14.35 orbits per day. 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 ~25–100 years. Orbital Radar tracks OAO 1 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

OAO 1 orbits at an average altitude of 776 km in the mid-LEO band, where atmospheric drag is minimal but radiation exposure remains manageable. Objects at this altitude persist for decades to centuries, making debris mitigation critical. This regime is popular for remote sensing constellations and scientific instruments that need stable, long-duration orbits. Within ±50 km of OAO 1’s average altitude, there are currently 439 active payloads and 2,382 tracked debris or rocket body fragments — notable neighbours include ONEWEB-0455. With an inclination of 35.0°, OAO 1 passes over latitudes between 35.0°N and 35.0°S, covering the tropical and temperate zones where most of the world’s population resides. Low-to-mid inclination orbits are efficient to reach from equatorial and mid-latitude launch sites. United States operates approximately 13,279 active satellites in total, of which 182 share a similar altitude band with OAO 1.