NASA's Dawn discovery mission will orbit the giant asteroid Vesta beginning in the summer of 2011. Four different near polar science orbits are planned. The lowest planned orbit at Vesta is called the Low Altitude Mapping Orbit or LAMO and is by far the most challenging to design and maintain due to the strong, nonspherical gravity expected there. This paper describes the orbit selection process. The true gravity field of Vesta remains highly uncertain. The proposed orbit selection process will be applied once sufficient gravity knowledge is obtained at higher orbits. The orbit selection process is applied here to a fictitious gravity field based on a Hubble space telescope shape model for Vesta assuming uniform density. The outcome of the process described here is a variety of stable orbits. However, Initially stable orbits at the LAMO altitude are not expected to remain stable operationally due to the unpredictable impulses resulting from the Dawn spacecraft thruster firings to de-saturate its momentum wheels. As a result, orbital maintenance maneuvers will be probably be necessary. This paper also briefly describes the statistical maneuver design process that resulted in the orbit maintenance plan.


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    Title :

    Low Altitude Mapping Orbit Design and Maintenance for the Dawn Discovery Mission at Vesta


    Contributors:

    Conference:

    AAS/AIAA Space Flight Mechanics Meeting ; 2011 ; New Orleans, LA, United States


    Publication date :

    2011-02-14


    Type of media :

    Conference paper


    Type of material :

    No indication


    Language :

    English




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    Whiffen, G.J. / American Astronautical Society / American Institute of Aeronautics and Astronautics | British Library Conference Proceedings | 2011



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    Dawn Discovery mission to Vesta and Ceres: Present status

    Russell, C. T. / Capaccioni, F. / Coradini, A. et al. | British Library Conference Proceedings | 2006


    Orbit Stability Analysis During the Orbit Transfer Around Vesta for the Dawn Mission

    Wissler, Matthew / Spencer, David / Melton, Robert | AIAA | 2004