The Earth orbiting space debris

The space debris population is similar to the asteroid belt, since it is subject to a process of high-velocity mutual collisions that affects the long-term evolution of its size distribution. Presently more than 10000 artificial debris particles with diameter larger than 10 cm (and more than 300000 with diameter larger than 1 cm) are orbiting the Earth and are monitored and studied by a large network of sensors around the Earth. Many different kind of objects compose the space debris population, produced by different source mechanisms ranging from high energy fragmentation of large spacecraft to slow diffusion of liquid metal. The impact against a space debris is a now serious risk that every spacecraft must face and can be evaluated with ad-hoc algorithms. The long term evolution of the whole debris population is studied with computer models allowing the simulation of all the known source and sinks mechanisms. One of these codes is described in this paper and the evolution of the debris environment, over the next 100 years, under different traffic scenarios is shown, pointing out the possible measures to mitigate the growth of the orbital debris population.