ABOUT THE DEMISABILITY OF PROPELLANT TANKS DURING ATMOSPHERIC RE-ENTRY FROM LEO

The concern about the on-ground risk caused by spacecraft fragments surviving atmospheric re-entry has significantly grown during the past decade, resulting in numerous activities of the space community like re-entry simulation tool development, improvement, and validation, as well as research for design-for-demise (D4D). The purpose of the first group is to increase the confidence in numerical re-entry risk predictions, while the second activity aims to develop new spacecraft design techniques which are likely to improve the demise behavior significantly. Standard (Titanium) propellant tanks for LEO (Low Earth Orbit) missions appear regularly within the group of spacecraft (satellite) components causing the highest on-ground risk, i.e. in the order of 20% for a 1-ton class Earth observation satellite. Thus, tanks are one of the primary targets for any D4D activity. Various ideas for demisable propellant tank concepts have been published recently, including aluminum tanks (e.g. based on aluminum-lithium alloys) or composite tanks (e.g. Carbon-fiber overwrapped metallic liners). The demonstration of the actual demisability of such new tank concepts has turned out to be difficult, sometimes even questionable. Intensive laboratory tests in arc-jet heated or plasma wind-tunnels and laser facilities have provided extensive results. Numerical simulations have been conducted to reproduce these experimental findings. This paper will contain a critical review of the latest experimental and numerical results about the demisability of satellite propellant tanks during atmospheric re-entry from LEO