HALCA (MUSES B)

HALCA (MUSES B) is an active satellite operated by Japan, launched on 1997-02-12 from Uchinoura, Japan. With over 29 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Medium Earth Orbit (MEO) at altitudes between 522 km and 21,123 km with an inclination of 31.2°. It travels at approximately 17,334 km/h (4.81 km/s), completing one full orbit every 6 hours 14 minutes — that’s roughly 3.85 orbits per day. Its orbital eccentricity of 0.5991 gives it a noticeably elliptical path, with significant altitude variation between perigee and apogee. It is part of the Ses constellation group. Orbital Radar tracks HALCA (MUSES B) in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

HALCA (MUSES B) orbits at an average altitude of 10,823 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 HALCA (MUSES B)’s average altitude, there are currently 2 active payloads and 5 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 31.2°, HALCA (MUSES B) passes over latitudes between 31.2°N and 31.2°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.