Modeling the near gravity field of small bodies and application in space missions

June 25, 2026

This thesis is about modeling and reconstructing the gravity fields of small Solar System bodies, such as asteroids, which play a key role in scientific exploration, planetary defense, and future resource utilization missions. Various gravity modeling techniques are reviewed and compared based on criteria such as accuracy, computational efficiency, and applicability to irregular bodies. From this comparison, three models (Polyhedral, Mascon, and Spherical Harmonics approaches) were selected for implementation and evaluation in MATLAB. Each model was applied to asteroid 433 Eros as a case study, demonstrating consistent and realistic representations of its gravitational field. A gravity field reconstruction framework was also developed, integrating an orbit points generator and an inversion algorithm based on the Mascon model with Tikhonov regularization. Synthetic experiments using homogeneous and heterogeneous bodies, as well as fly-by configurations, were conducted to assess the influence of parameters such as orbit altitude, measurement density, and mass distribution. Results indicate that measurement altitude is the dominant factor affecting the accuracy of gravity recovery, though its impact can be mitigated by increasing the number of observations. The thesis confirms the effectiveness and complementarity of the three selected models for small-body missions and provides a foundation for future work in hybrid model development, enhanced orbit simulation, and the inclusion of realistic noise in gravity inversion algorithms.

Authors in the community:

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  D

  Daniel Pereira Barata

  ist199474

Supervisors of this institution:

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  P

  Paulo Jorge Soares Gil

  ist12912

mechanical-engineering - Mechanical engineering

eng - English

Instituto Superior Técnico