ESA Project: Fragmentation Consequence Analysis for LEO and GEO orbits (2012 – 2014):
This research project was funded by ESA’s General Studies Programme in the frame of the GreenOPS initiative (http://gsp.esa.int/greenops), with the Institute of Aerospace Systems as Prime Contractor and the Fraunhofer Ernst-Mach-Institute in Freiburg and Airbus Defence and Space as project partners. In the frame of this project, four major questions are to be answered:
- What effect does a central impact vs a lateral impact have? Models that are currently used to model a collision between satellites decide based on an impact Energy-to-Mass (EMR) threshold if the collision is assumed to be catastrophic (thus a complete destruction of the involved spacecraft is the consequence) or non-catastrophic. Indications exist though indicating that the impact angle as well as the impact position has a large influence on the final collision influence. This is studied by the Fraunhofer Ernst-Mach-Institute (EMI), using hypervelocity impact tests.
- What is the environmental criticality of a specific object? The environmental criticality is a term to describe the risk posed by any object within the space population to all other objects to collide catastrophically. This risk is set together from two factors: First, the probability of the object itself to collide catastrophically and second, the impact this would have on the rest of the population. As it changes over time, this factor is determined for a defined set of characteristic spacecraft using Monte-Carlo simulations of the long-term evolution of the space debris environment. As the whole approach is very computationally costly, an analytical model (SANE – Simple ANalytical Evolution) was derived to reproduce the results from Monte-Carlo simulations in a much faster fashion and derive the criticality using it. Following, this factor is used to derive a criticality list of all larger spacecraft currently in orbit. For consistency, this approach was compared to a different criticality criterion provided by Airbus Defence and Space.
- How will the collision rate change, if a specific object fragments?
There are two different aspects to the question: First, what is the short term impact directly after the event. Second, what is the long-term effect of a single fragmentation event and thus the enhancement of the collisional cascading effect.
- How can different aspects of a debris environment evolution be expressed in terms of simple input parameters?
Aspects covered by this aspect include parameters such as the decay rate of a population of intact bodies, the collision –rate as a function of large objects or the explosion rate as a function of intact bodies.
Publications in the frame of the project:
Kebschull C., Radtke J., Krag H.,"Deriving a Priority List Based on the Environmental Criticality", Presented at the 65th International Astronautical Conference, Toronto, Canada, 29.09 - 03.10 2014, Paper IAC-14,A6,P,48x26173
Kebschull C., Scheidemann P., Hesselbach S., Radtke J., Braun V., Krag H., "Simulation of the space debris environment in LEO using an analytical approach", Presented at the 40th COSPAR Scientific Assembly, Moscow, Russia 2 - 10 August 2014, Paper PEDAS.1-0011-14
Kebschull C., Braun V., Flegel S., Reihs B., Hesselbach S., Gelhaus J., Möckel M., Radtke J., Wiedemann C., Krag H., Vörsmann P., "A Simplified Approach to Analyze the Space Debris Evolution in the Low Earth Orbit", 64th International Astronautical Congress, Beijing, China 23.-27. September 2013, Paper IAC-13,A6,2,3x19121
Radtke J., Flegel S., Roth S., Krag H., Deriving the Spacecraft Criticality from Monte-Carlo Simulations of the Space Debris Environment, Presented at the 65th International Astronautical Congress 2014 (IAC 2014), 29. Sept. – 03. Oct. 2014, Toronto, Canada, Paper ID A6,2,6,x25584
Radtke J., Flegel S., Gelhaus J., Möckel M., Braun V., Kebschull C., Wiedemann C., Krag H., Merz K., Vörsmann P., Revision of Statistical Collision Analysis for Objects Inside of Satellite Constellations, Poster Presented at the 64th International Astronautical Congress 2013 (IAC 2013), 23. - 27. September 2013, Beijing, China, paper IAC - 13,A6,P,8.p1x18951
Radtke J., Flegel S., Gelhaus J., Möckel M., Braun V., Kebschull C., Wiedemann C., Krag H., Merz K., Vörsmann P., Überarbeitung der statistischen Kollisionsanalyse für Objekte innerhalb von Stallitenkonstellationen, DGLR-Jahrestagung 2013, Stuttgart