Dynamics of a triaxial gyrostat at a Lagrangian equilibrium of a binary asteroid

The non-canonical Hamiltonian dynamics of a triaxial gyrostat in Newtonian interaction with two punctual masses is considered. This serves as a model for the study of the attitude dynamics of a spacecraft located at a Lagrangian equilibrium point of the system formed by a binary asteroid and a spacecraft. Using geometric-mechanics methods, the approximated dynamics that arises when developing the potential in series of Legendre functions and truncating the series to the second harmonics is studied. Working in the reduced problem, the existence of equilibria in Lagrangian form are studied, in analogy with classic results on the topic. In this way, the classical results on equilibria of the three-body problem, as well as other results by different authors that use more conventional techniques for the case of rigid bodies, are generalized. The rotational Poisson dynamics of a spacecraft located at a Lagrangian equilibrium and the study of the nonlinear stability of some important equilibria are considered. The analysis is done in vectorial form avoiding the use of canonical variables and the tedious expressions associated with them.