Summary: We formulate the canonical equations of motion of a spacecraft of complex shape under the joint effects of Earth oblateness and direct solar radiation pressure. The shape of the satellite is modeled as an axisymmetric body with an antenna emitting or receiving a radio beam. This model can describe the main effects for telecommunication satellites. The attitude of the satellite is assumed stabilized, such that the axis of the symmetric part alignes along the tangent to the orbit. We expand the Hamiltonian in terms of Delaunay elements augmented in order to remove the time dependence of the Hamiltonian. Part II presents a procedure for calculation of the position and velocity, and gives conditions for resonance.