Analysis of the space debris environment with SDM 3.0

The Space Debris Mitigation long-term analysis program (SDM) has been originally developed in the early 90s' to study the long-term evolution of orbital debris and to evaluate the effectiveness of the mitigation measures. In the last two years SDM has been significantly upgraded to Version 3.0 under an ESA/ESOC Contract. In the paper the improvements made to the new software are described. With this upgraded tool the long-term evolution of the space debris population with mass larger than 1 mg, from LEO up to 40 000 km of altitude, is studied. Building on a reference up-to-date Business As Usual scenario, several mitigation measures are simulated and their effectiveness is tested. The results show that the passivation of spacecraft and upper stages (in order to prevent future explosions) and the deorbiting or re-orbiting of spacecraft at end-of-life (either to orbits with a limited lifetime or to a super-LEO disposal zone) can stabilise the population of objects larger than 10 cm in LEO for the next century. The effect of different residual lifetimes is discussed in the paper. The sensitivity of the results to the adoption of the new NASA EVOLVE 4 breakup models is then discussed. It is found that with the adoption of this last breakup model the population of objects larger than 10 cm in LEO keeps growing, though slowly, even in the mitigated scenarios. Therefore, if the new NASA models are assumed, the proposed mitigation scenarios are not able to stabilize the population of debris larger than 10 cm in LEO.