DELTA 1 R/B

DELTA 1 R/B is a spent rocket body associated with United States, launched on 1983-05-26 from Vandenberg SFB, California on the Exosat launch. With over 43 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Medium Earth Orbit (MEO) at altitudes between 760 km and 2,514 km with an inclination of 72.3°. It travels at approximately 25,399 km/h (7.06 km/s), completing one full orbit every 119 minutes — that’s roughly 12.10 orbits per day. Its orbital eccentricity of 0.1095 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 DELTA 1 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.

DELTA 1 R/B orbits at an average altitude of 1,637 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 DELTA 1 R/B’s average altitude, there are currently 23 active payloads and 141 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 72.3°, DELTA 1 R/B passes over latitudes between 72.3°N and 72.3°S, covering most populated land masses in both hemispheres. This mid-inclination band balances global coverage with efficient launch energy requirements. United States operates approximately 12,413 active satellites in total.