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  • Autonomous Navigation at Small Bodies

    Paper number

    IAC-09.A3.I.10

    Author

    Mr. Jeroen Melman, Delft University of Techonology (TU Delft), The Netherlands

    Coauthor

    Dr. Erwin Mooij, Delft University of Techonology (TU Delft), The Netherlands

    Coauthor

    Ir Ron Noomen, Technical University of Delft (TUDelft), The Netherlands

    Year

    2009

    Abstract
    Various space agencies are making plans to send spacecraft to small bodies: to orbit around it, to impact it or to land on it. For example, within ESA’s Cosmic Vision programme the Marco Polo mission has been selected, a sample return mission to a Near Earth Asteroid. Furthermore, a clear tendency towards on-board autonomy can be recognised: not only to reduce mission costs, but also because autonomy is indispensable for real-time close-proximity operations at such distances. In this light the research described below is performed.
    
    The research focuses on precise and fast determination and propagation of orbits around small bodies. Propagation algorithms are developed that are compliant with future on-board requirements, in order to further enhance mission autonomy. These algorithms can then be applied in the on-board navigation filters. Having advanced propagation algorithms available on-board will become a facilitator for cost-efficient and new mission scenarios. 
    
    A clear focus is on orbits around irregular bodies, since this is a common occurrence within the class of small bodies and since these irregularities pose particular challenges. To this end, we model the environment of asteroids. The irregular gravity is modelled by both conventional spherical harmonics and geometric shape models, based on polyhedra. It can be shown that for accuracy reasons the use of polyhedra is necessary when close to the surface. When further away from the body the use of spherical harmonics will give a higher efficiency, while retaining the required accuracy.
    
    Multiple test cases have been defined that underline this. One of the test cases is asteroid Steins, where the Rosetta spacecraft flew by in September 2008. It is known as ‘The Diamond in the Sky’, and a basic diamond shape has been used. This helped us to establish that even with a rough knowledge of the gravity field, the speed and accuracy of the propagation and navigation algorithms is sufficient to ensure a safe science orbit.
    Abstract document

    IAC-09.A3.I.10.pdf

    Manuscript document

    IAC-09.A3.I.10.pdf (🔒 authorized access only).

    To get the manuscript, please contact IAF Secretariat.