The Hamiltonian dynamics of the two gyrostats problem

The problem of two gyrostats in a central force field is considered. We pro ve that the Newton-Euler equations of motion are Hamiltonian with respect t o a certain non-canonical structure. The system posseses symmetries. Using them we perform the reduction of the number of degrees of freedom. We show that at every stage of the reduction process, equations of motion are Hamil tonian and give explicit forms corresponding to non-canonical Poisson brack ets. Finally, we study the case where one of the gyrostats has null gyrosta tic momentum and we study the zero and the second order approximation, show ing that all equilibria are unstable in the zero order approximation.