reorbiting maneuvers; Figure 7-5 shows the approximate number of GEO reorbiting maneuvers compared to the number of spacecraft launched to GEO by year. These reorbiting maneuvers have typically placed spacecraft in orbits from 50 to 1,000 km above GEO, though a few spacecraft have been reorbited to orbits below GEO.

Moving a space object into a disposal orbit reduces the collision hazard in the object's initial orbital region, but increases the collision hazard in its new orbital region. Objects moved to disposal orbits can still contribute to the debris hazard in their original orbit, however, since debris generated through collisions or explosions that take place in disposal orbits may intersect the original orbit. (Increased implementation of passivation measures should, however, result in fewer explosions in future disposal orbits.) This is particularly important in high-altitude regions, where an explosion or collision can send a large number of fragments far above and below their initial orbital altitude. Figure 7-6 shows a prediction of the effect of a spacecraft breakup in GEO on the large object flux in nearby altitudes. (This figure should not be compared with the GEO flux depicted in Figure 4-5 because that figure depicts only the flux due to cataloged [typically larger than 1 m in diameter] objects.) Clearly, the

FIGURE 7-5 GEO spacecraft reorbiting maneuvers. SOURCE: Kaman Sciences Corporation.