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    • Space Safety Trajectory Optimization with Break-ups and Impacts using ASTOS at ESA

    Paper number

    IAC-07-A6.2.09

    Author

    Dr. Guillermo Ortega, European Space Agency (ESA)/ESTEC, The Netherlands

    Coauthor

    Diana Gallardo, European Space Agency (ESA)/ESTEC, The Netherlands

    Coauthor

    Sven Weikert, Germany

    Coauthor

    Ms. Ana Blasco, European Space Agency (ESA)/ESTEC, The Netherlands

    Year

    2007

    Abstract
    This paper describes the coupling of the optimization 
software ASTOS with a tool for splashdown analysis of 
separated stages, called EDA (Entry Destruction 
Analysis) and a Risk Analysis Module called RAM.

ASTOS is a main reference tool for trajectory 
optimization at ESA. It is also used to compute demise and break up os rocket stages and re-entry vehicles and analyze the risk to populated areas.

ASTOS software is a simulation and optimization environment to compute optimal trajectories for a variety of complex multi-phase optimal control problems. 

It consists of fast and powerful optimization programs, PROMIS, CAMTOS, SOCS and TROPIC, that handle large and highly discretized problems, a user interface with multiple plot capability, and GISMO, an integrated graphical iteration monitor to review the optimization process and plot the state and control histories at intermediate steps during the optimization.

The optimization programs used by ASTOS (and in general any trajectory optimization tool currently in use in Europe) use Non-Linear Programming (NLP) mathematical solvers like NPSOL, SLSQP, SLLSQP, and SNOPT. 

These solvers use Sequential Quadratic Programming (SQP) mathematical algorithms to find the solution of the non-linear programming problems in trajectory optimization. 


ASTOS comprises an extensive model library, which allows launcher trajectory optimization without programming work. 

EDA considers not only a stage break-up, but also 
melting of the fragments, taking diverse materials and 
shapes into account. 

The paper discusses hazard due to stage impact, considering the ESA launchers as examples. Previous approaches for the impact point calculation during trajectory optimization are presented. Subsequently the results of these approaches are compared to EDA results. 

This paper shows that ASTOS and the EDA and RAM extensions can calculate impact points with satisfactory accuracy and calculation time. It is demonstrated how ASTOS transforms impact points calculated by EDA into a constraint which is analyzable by the optimization algorithm. A sensitivity analysis of the material properties and atmosphere data gives information on the quality of the results.
    Abstract document

    IAC-07-A6.2.09.pdf

    Manuscript document

    IAC-07-A6.2.09.pdf (🔒 authorized access only).

    To get the manuscript, please contact IAF Secretariat.