DELTA 4 R/B

DELTA 4 R/B is a spent rocket body associated with United States, launched on 2011-07-16 from Cape Canaveral, Florida on the GPS SVN 63 launch. After 15 years in orbit, it continues to be tracked by global surveillance networks. It orbits in Medium Earth Orbit (MEO) at altitudes between 20,129 km and 22,149 km with an inclination of 57.0°. It travels at approximately 13,703 km/h (3.81 km/s), completing one full orbit every 12 hours 37 minutes — that’s roughly 1.90 orbits per day. Spent rocket bodies like DELTA 4 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 4 R/B orbits at an average altitude of 21,139 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 4 R/B’s average altitude, there are currently 0 active payloads and 21 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 57.0°, DELTA 4 R/B passes over latitudes between 57.0°N and 57.0°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.