DELTA 4 R/B

DELTA 4 R/B is a spent rocket body associated with United States, launched on 2009-06-27 from Cape Canaveral, Florida on the GOES O launch. After 17 years in orbit, it continues to be tracked by global surveillance networks. It orbits in Medium Earth Orbit (MEO) at altitudes between 6,628 km and 35,085 km with an inclination of 13.2°. It travels at approximately 13,774 km/h (3.83 km/s), completing one full orbit every 12 hours 25 minutes — that’s roughly 1.93 orbits per day. Its orbital eccentricity of 0.5226 gives it a noticeably elliptical path, with significant altitude variation between perigee and apogee. 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 20,857 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 3 active payloads and 14 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 13.2°, DELTA 4 R/B passes over latitudes between 13.2°N and 13.2°S, concentrating coverage over equatorial and near-equatorial regions. Low-inclination orbits maximise revisit rates over specific tropical zones. United States operates approximately 12,413 active satellites in total, of which 3 share a similar altitude band with DELTA 4 R/B.