Numerical investigation on the standard catastrophic break-up criteria

Paper number

IAC-19,A6,2,1,x53115

Author

Dr. Martin Schimmerohn, Germany, Fraunhofer EMI

Coauthor

Dr. Pascal Matura, Germany, Fraunhofer EMI

Coauthor

Mr. Erkai Watson, Germany, Fraunhofer - Institut für Kurzzeitdynamik, Ernst-Mach-Institut (EMI)

Coauthor

Dr. Nathanaël Durr, Germany, Fraunhofer EMI

Coauthor

Mrs. Tiziana Cardone, The Netherlands, ESA - European Space Agency

Coauthor

Mr. Don de Wilde, The Netherlands, ESA - European Space Agency

Coauthor

Dr. Holger Krag, Germany, European Space Agency (ESA)

Coauthor

Dr. Frank Schäfer, Germany, Fraunhofer EMI

Year

2019

Abstract

While the major contribution of space debris today stems from explosion events, forecasts predict that collisions will be the dominant space debris source in the mid-term future, when a critical spatial density of satellites is reached. It is essential for environmental modeling and risk analysis to describe collisional breakup events in terms of resulting fragment characteristics and to understand their dependence on the collision scenario. The NASA Standard Satellite Breakup Model (SSBM) has been adopted by major space agencies for characterizing hypervelocity spacecraft breakups for debris environment modeling. The SSBM is an empirical model based on data from ground tests and observations of on-orbit events. It is a simple model that only uses the mass of the colliding objects and their collision velocity as input parameters. The distinction between catastrophic and non-catastrophic collisions is based on an energy-to-mass ratio (EMR) criterion, which defines catastrophic breakups to occur for an EMR $>$40 Joule/gram. The simplicity and the empirical nature of the SSBM provide flexibility and fast analyses but also limit the ability to model complex scenarios and depends on the available data.\\\\
Besides complex ground experiments like the DebriSat project, we propose to use numerical simulations in order to enhance the data base in a practical and effective way. We established the software tool PHILOS-SOPHIA for systematically studying the effects of on-orbit hypervelocity collisions for a wide range of collision conditions and for complex spacecraft models. PHILOS-SOPHIA is based on a specialized hydrocode solver, which was extensively validated in the context of missile defence studies. We show the tool’s ability to simulate directionality and shape effects by directly comparing with hypervelocity impact experiments. The analysis’ needs dictate the complexity of the modeling and the required computational effort.\\\\
For analyzing the standard EMR breakup criterion, we simulated six different scenarios using ESA’s LOFT spacecraft and CubeSat impactors in different collision conditions. In the detailed fragmentation analysis, we find both good agreements and clear deviations between the hydrocode results and the SSBM predictions. Particularly, the collision geometry strongly influences the fragmentation damage and the area-to-mass distributions. Depending on the collision vector, grazing impacts may result in higher or lower fragmentation in comparison with impacts on the center of mass. The EMR criterion does not reflect this complexity and we recommend performing more research on this topic. PHILOS-SOPHIA, thoroughly backed by advanced experiments, can be the tool for this purpose.

Abstract document

IAC-19,A6,2,1,x53115.brief.pdf

Manuscript document

IAC-19,A6,2,1,x53115.pdf (🔒 authorized access only).

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