M-5 DEB

M-5 DEB is a tracked piece of space debris attributed to Japan, launched on 1997-02-12 from Uchinoura, Japan on the MUSES-B launch. With over 29 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Medium Earth Orbit (MEO) at altitudes between 274 km and 11,172 km with an inclination of 31.4°. It travels at approximately 20,667 km/h (5.74 km/s), completing one full orbit every 3 hours 41 minutes — that’s roughly 6.52 orbits per day. Its orbital eccentricity of 0.4506 gives it a noticeably elliptical path, with significant altitude variation between perigee and apogee. As orbital debris, M-5 DEB poses a potential collision risk to operational satellites in nearby orbits and is continuously monitored by the U.S. Space Surveillance Network and other tracking systems.

M-5 DEB orbits at an average altitude of 5,723 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 M-5 DEB’s average altitude, there are currently 0 active payloads and 6 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 31.4°, M-5 DEB passes over latitudes between 31.4°N and 31.4°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. Japan operates approximately 189 active satellites in total.