This activity aims at the advancement of environment status and prediction models, to be used for the impact risk assessment in spacecraft design and for the analysis of the efficiency of mitigation and remediation measures.

The goal is to arrive at operational implementations that incorporate the latest and best knowledge on the environment, highest accuracy long-term propagation in order to assist spacecraft developers in their risk assessment, as well as stakeholders in identifying and negotiating mitigation and remediation measures on multinational level.

 

 

Environment prediction models (like MASTER) are by no means static and require continuous improvements to keep the pace with an ever-changing highly dynamic space debris environment. New types of measurements (as, e.g., from potential in-situ sensors), newly discovered debris sources (as the release of MLI foils), and additional severe debris generating events (like the Chinese ASAT test of January 2007 and the Iridium-33/Cosmos-2251 collision in 2009) need to be reflected. These models are essential for the analysis of the impact risk on spacecraft, design of shields and vulnerability assessments. They also form the baseline for environment prediction models (like DELTA, Damage, SDM, LUCA), which make use of launch traffic models and collision risk assessment to predict long-term trends and collision rates in the environment.

 

Such tools allow to simulate the application of various mitigation measures and the level of fulfilment of such measures. They will return the environmental trend in response to the measures applied. Such models also allow to simulate various active removal scenarios and allow to identify the most efficient approaches. These models heavily rely on assumptions for the energy levels required to break-up spacecraft, fragmentation models and accurate long-term simulators.

 

The major technological achievements to be reached and the activity associated tasks are:

 

• Refinement of existing models for lately discovered events and sources (collisions and MLI release) on the basis of measurement data from in-situ sensors and terrestrial sensors (OGS, TIRA, EISCAT).

• Research and development in the area of collisional break-up monitoring oriented towards the Iridium/Cosmos and Fengyun-1C examples.

• Accompanying hypervelocity impacts experiments near the critical energy- tomass ration, shallow impact angles.

• Improvement of semi-analytical, fast and accurate long-term propagators along with a reasonable handling of non-conservative perturbations, such as atmospheric drag and solar pressure for a wide range of area-to-mass ratios.

• Establishment of traceable criteria for the initiation of catastrophic collisions.