Thermite-for-Demise (T4D): Experimental analysis of heat transfer principles and preliminary sizing of an application

The use of exothermic reactions to aid satellite demise during re-entry is under investigation. An energetic material, if stored on board, could passively ignite thanks to the heat load experienced by the spacecraft during re-entry, and ease its complete ablation. Thermites are good candidates for this application because of their high energy density and relative stability. Their effectiveness is strictly related to the heat transfer efficiency between the ignited powder and its confining vessel. Experiments in non-relevant environment were conducted for Al+Fe2O3 thermite to quantify this value. The average heat transfer efficiency was quantified at 60%, with respect to the theoretical heat release of the mixture. A novel numerical model implementing a T4D application, named TRANSIT (TRANsatmosferic SImulation Tool), is presented and verified with respect to two commercial software packages. In particular, literature data for SAM and dedicated simulations for SCARAB have been used in this phase. TRANSIT is then employed to preliminarily size a thermite charge to aid spacecraft demise during re-entry for three simple re-entering objects. A genetic algorithm is employed to optimize the thermite to spacecraft mass ratio, assuring complete demise.