Forecasting numbers of post-mission satellites of major constellations, and mitigation methods

Abstract Surprisingly large numbers of post-mission satellites will be decaying towards re- entry at any time, after the mega-constellations are highly populated and one mission lifetime has expired. This study shows calculations that there will be many thousands at one time. And these post-mission satellites will have substantial additional issues for astronomers. Mitigation methods to be considered include a larger satellite in each orbital ring, to service or de-orbit Internet satellites that have failed or depleted their propellant, as well as joint research projects to develop and mature subsystems to deploy drag balloons, drag tethers, or other methods to de- orbit more rapidly. Proposals include the potential for a joint research facility at an appropriate existing space research centre.