Jonathan's Space Pages

Space Debris Clouds

Catalog of Space Debris Clouds - Introduction


Many of the tracked space debris objects in Earth orbit belong to specific debris clouds - by which I mean that they originate from a single parent object that broke up, and have broadly similar orbital parameters. Some orbital parameters, such as orbital inclination, usually remain relatively constant over decades, so that even objects discovered long after the originating event can often be associated with a specific cloud with high confidence. The Debris Clouds catalog lists these clouds and their characteristic orbital parameters. The catalog has similarities with the classic source on this issue, Nicholas Johnson's History of On-Orbit Satellite Fragmentations, released by the NASA JSC Orbital Debris Program Office (ODPO) and taken over by Philip Anz-Meador after Nick's retirement. At this writing the History is in its 15th edition; it is available at the ODPO website.


The traditional way to represent a debris cloud graphically is the Gabbard diagram (developed by John Gabbard of NORAD in the 1960s), which charts object perigee and apogee versus orbital period. The ODPO document presents these for each event; rather than replicate those, I have chosen to experiment with different representations, described below. The ODPO document also excludes some apparent debris clouds without explanation; the present catalog therefore does not have exactly the same list of clouds.


I consider four main types of debris cloud:

A fifth case is that of an aerodynamic breakup. As an elliptical orbit satellite approaches reentry, items like solar panels and booms can break off during perigee passages. These breakups don't usually result in large numbers of cataloged debris, and are not included here.