PEGASUS R/B

PEGASUS R/B is a spent rocket body associated with United States, launched on 1998-10-23 from Esrange, Sweden on the SCD-2 launch. With over 28 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 716 km and 748 km with an inclination of 25.0°. It travels at approximately 26,968 km/h (7.49 km/s), completing one full orbit every 99 minutes — that’s roughly 14.48 orbits per day. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~25–100 years. Spent rocket bodies like PEGASUS R/B are among the largest pieces of uncontrolled space debris and are priority targets for collision avoidance manoeuvres and future active debris removal efforts.

PEGASUS R/B orbits at an average altitude of 732 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 PEGASUS R/B’s average altitude, there are currently 353 active payloads and 1,868 tracked debris or rocket body fragments — notable neighbours include TERRA, AQUA, LANDSAT 9. With an inclination of 25.0°, PEGASUS R/B passes over latitudes between 25.0°N and 25.0°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 12,413 active satellites in total, of which 142 share a similar altitude band with PEGASUS R/B.