Collision risk assessment for perturbed orbits via validated global optimization

Paper number

IAC-11,A6,2,3,x10853

Author

Mr. Alessandro Morselli, Politecnico di Milano, Italy

Coauthor

Dr. Roberto Armellin, Politecnico di Milano, Italy

Coauthor

Dr. Pierluigi Di Lizia, Politecnico di Milano, Italy

Coauthor

Prof. Franco Bernelli-Zazzera, Politecnico di Milano, Italy

Year

2011

Abstract

A method intended to assess the occurrence of impacts between satellite 
and space debris is presented. The method is based on the computation of 
the Minimal Orbit Intersection Distance (MOID) between two perturbed orbits. 

The MOID is obtained by means of a global optimization, using a global optimizer 
based on Taylor Models. The position of the orbiting objects is described through analytical solutions that take into account zonal harmonics and 
atmospheric drag. The global optimizer searches the local minimum of the 
square distance between the two orbits, that is a function of the two true 
anomalies and time. The optimization is capable of providing tight enclosures 
of the global minimum.

The method is applied to the case of a Sun-synchronous orbit and an equatorial 
elliptic orbit. Due to the effect of the Earth zonal harmonics, the orbital 
plane of the Sun-synchronous orbit performs a complete rotation around Earth's
North Pole direction. The relative geometry of the two orbits is such that four 
intersections occur within one year window.

A second test-case demonstrates the ability to predict 
the effect of drag perturbations. Two LEO orbits are considered, one of which 
is strongly influenced by atmospheric drag. The decrease of semi-major axis 
leads to an intersection between the two orbits in the considered time 
span.

The method is capable to recognize correctly the intersections between 
two orbits. It can thus identify the conditions in which close 
approaches between satellites and debris occur. The method is intended to 
perform a fast screening of all possible combinations of orbiting object, since 
the use of analytical theory cuts down simulation time.

Abstract document

IAC-11,A6,2,3,x10853.brief.pdf

Manuscript document

IAC-11,A6,2,3,x10853.pdf (🔒 authorized access only).

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