BB4

BB4 is an active satellite operated by US Space Development Agency (United States), launched on 2023-09-02 from Vandenberg Space Force Base, United States on the SDA-0B launch. It orbits in Low Earth Orbit (LEO) at altitudes between 619 km and 633 km with an inclination of 81.0°. It travels at approximately 27,172 km/h (7.55 km/s), completing one full orbit every 97 minutes — that’s roughly 14.84 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~10–25 years. Orbital Radar tracks BB4 in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

BB4 orbits at an average altitude of 626 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 BB4’s average altitude, there are currently 1,020 active payloads and 873 tracked debris or rocket body fragments — notable neighbours include ONEWEB-0050. This makes it one of the more crowded altitude bands, containing roughly 5.5% of all active satellites. With an inclination of 81.0°, BB4 passes over latitudes between 81.0°N and 81.0°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 13,204 active satellites in total, of which 519 share a similar altitude band with BB4.