RELAY 1 (A-15)

RELAY 1 (A-15) is an active satellite operated by GSFC (United States), launched on 1962-12-13 from Cape Canaveral Space Force Station, United States. After more than 64 years in orbit, it is one of the longest-surviving objects in the space catalogue. It orbits in Medium Earth Orbit (MEO) at altitudes between 1,329 km and 7,428 km with an inclination of 47.5°. It travels at approximately 21,922 km/h (6.09 km/s), completing one full orbit every 3 hours 5 minutes — that’s roughly 7.78 orbits per day. Its orbital eccentricity of 0.2837 gives it a noticeably elliptical path, with significant altitude variation between perigee and apogee. Orbital Radar tracks RELAY 1 (A-15) in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

RELAY 1 (A-15) orbits at an average altitude of 4,379 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 RELAY 1 (A-15)’s average altitude, there are currently 1 active payload and 2 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 47.5°, RELAY 1 (A-15) passes over latitudes between 47.5°N and 47.5°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. United States operates approximately 13,276 active satellites in total.