PEGASUS R/B

PEGASUS R/B is a spent rocket body associated with United States, launched on 1996-08-21 from Vandenberg Space Force Base, United States on the FAST launch. With over 30 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Medium Earth Orbit (MEO) at altitudes between 343 km and 2,987 km with an inclination of 82.9°. It travels at approximately 25,354 km/h (7.04 km/s), completing one full orbit every 120 minutes — that’s roughly 12.03 orbits per day. Its orbital eccentricity of 0.1645 gives it a noticeably elliptical path, with significant altitude variation between perigee and apogee. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is thousands of 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 1,665 km in Medium Earth Orbit, the region between LEO and GEO (2,000–35,786 km). MEO’s higher altitude gives each satellite a much larger ground footprint than LEO, meaning fewer spacecraft are needed for global coverage — but signal latency is higher and radiation from the Van Allen belts is a significant design constraint. Within ±50 km of PEGASUS R/B’s average altitude, there are currently 23 active payloads and 120 tracked debris or rocket body fragments. This is a relatively sparse altitude band, containing less than 1% of all active satellites. With an inclination of 82.9°, PEGASUS R/B passes over latitudes between 82.9°N and 82.9°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 13,201 active satellites in total, of which 3 share a similar altitude band with PEGASUS R/B.