ISIS 1 DEB

ISIS 1 DEB is a tracked piece of space debris attributed to Canada, launched on 1969-01-30 from Vandenberg SFB, California on the Isis A launch. After more than 57 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 567 km and 2,556 km with an inclination of 88.4°. It travels at approximately 25,519 km/h (7.09 km/s), completing one full orbit every 117 minutes — that’s roughly 12.27 orbits per day. Its orbital eccentricity of 0.1254 gives it a noticeably elliptical path, with significant altitude variation between perigee and apogee. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is thousands of years. As orbital debris, ISIS 1 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.

ISIS 1 DEB orbits at an average altitude of 1,562 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 ISIS 1 DEB’s average altitude, there are currently 33 active payloads and 241 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 88.4°, ISIS 1 DEB passes over latitudes between 88.4°N and 88.4°S, providing near-global coverage including the polar regions. Polar and near-polar orbits are used for reconnaissance, weather monitoring and Earth-observation missions that need to image every part of the planet. Canada operates approximately 67 active satellites in total.