Long Term Evolution of Earth Orbiting Objects

The evolution of the orbiting debris population larger than 1 mm has been simulated for 100 yr assuming four diierent space policy scenarios. The study was made possible by the development of two speciic software codes, including the relevant source and sink mechanisms and several model options. A sensitivity analysis has shown that the results are relatively insensitive to the adoption of diierent, and reasonable, models and parameters, with at most a diierence of a factor 2 in the total number of particles generated. However, the space policy measures endorsed worldwide may affect signiicantly, in qualitatitive and quantitative terms, the orbital debris long term evolution in the near Earth space. The simulations performed show that maintaining the current launch rate and operational practices will produce in the next century not only an increase of spent rocket bodies and dead spacecraft, but also a dramatic increase (by a factor 20 or larger) in the number of small particles. The most eeective way to slow down this undesired trend would be to stop as soon as possible all explosions in space; however, the only way to reverse the critical density conditions already observed in the most crowded regions of the near Earth space would imply the adoption of much more drastic actions , as the deorbiting of upper stages and spacecraft at the end of their operational life.