Fragmentation debris makes up 42% of the cataloged space object population and probably a much larger fraction of the uncataloged population. Since there have been only two confirmed space object breakups to date due to collisions (both intentional military tests), the vast majority of this debris is believed to have been created in explosive breakups of spacecraft and rocket bodies. This population of debris spans all size ranges and is distributed widely, although concentrated near the orbits in which it was created. Figure 7-1 projects how a typical explosion in LEO (producing 300 cataloged objects) could moderately increase the spatial density of cataloged objects in orbits hundreds of kilometers above.

FIGURE 7-1 Predicted effect of satellite breakup at 1000 km. Top curve is initial spatial density distribution with altitude. Time interval between lower curves is 400 years. SOURCE: Kessler, 1991.