VEGA 4th Stage Direct Re-Entry Survivability Analysis and Casualty Risk Assessment

A key task in launch vehicle (LV) system design process consists in the estimation of upper stage fragmentation during atmospheric re-entry once accomplished the launcher mission, and the related probability of making on-ground casualties. As a European launcher operating from French Guyana, VEGA has to abide by ESA debris mitigation rules, and by the French Law on Space Operations (LOS). The second flight of VEGA aims at demonstrating the versatility of the launcher by performing a multi-payload launch with different target orbits. From a safety point of view, the compliance of VEGA to the LOS will also be extended through the performance of the direct deorbiting of its upper stage, the AVUM, at the end of its mission. Indeed, during the qualification flight, VEGA had submitted to the safety authorities the derogation envisaged by the LOS: under certain conditions, it allows the indirect re-entry of the launcher's upper stage, provided it shall do so in less than 25 years.