LEO constellations - Quo vadis after end-of-mission?

Constellations in low-Earth orbit (LEO) will increase the number of debris objects if they are not removed from their orbit after end of mission. This paper addresses two issues: the technical aspects dealing with the collision risk during de-orbiting (calculated with the MASTER model) and the political and legal aspects covering the liability question. Prerequisites for a code of conduct are outlined that could be agreed upon internationally to encourage spacecraft operators to de-orbit their spacecraft. If such measures were to be taken, a mass accumulation could be prevented at disposal orbits above 2000 km, thus preserving these regions useful for future generations.