Design not to Demise

As the number of spacecraft increases, the sustainability of their end-of-life management is also becoming increasingly important. To date, the majority of such objects, whether actively controlled or passively descending, re-enter the Earth’s atmosphere at the end of their mission, where they burn up partially or almost completely. However, the systematic burning up of spacecraft in the Earth’s atmosphere generates emissions with effects on the climate and the environment that are as yet unforeseeable. Although orbital launch vehicle stages account for only around 20% of all re-entering spacecraft, their mass means they are responsible for around 50% of the total mass, making them a major driver of emissions from burning-up spacecraft. To this end, we are developing the ‘Design not to Demise (Dnot2D)’ concept – that is, upper stage concepts and system designs that enable a controlled and material-conserving re-entry, whilst avoiding or specifically controlling combustion. The aim is to reduce the release of pollutants and particles into the atmosphere and to establish more sustainable end-of-life strategies for space systems. Non-destructive return would also make it possible to establish recycling or partial re-use as a long-term sustainable strategy in spaceflight.

The robustness of a re-entering object can be enhanced, for example, through adjustments to the material, the use of thermal protection systems or changes to its geometry, such as deployable elements. To understand which technologies and concepts could enable this type of re-entry, we are investigating, using existing launch vehicle systems, the loads encountered during re-entry and the potential for adapting their designs whilst minimising the impact of such changes on the primary mission. To this end, we utilise both in-house and external numerical simulation tools. The trajectories and resulting loads are initially calculated using numerical propagation methods. For more detailed investigations, high-resolution flow simulations are also carried out using PICLas. The robustness of the developed designs is finally verified using Finite Element Method (FEM) analyses. 

This research was supported by ArianeGroup as part of a Research Training Group.