Satellite Laser Ranging (SLR) systems successfully measure attitude and spin period of Envisat. During the International Laser Ranging Service (ILRS) campaign the SLR stations observed the satellite and provided measurements that allow determination of the attitude and the spin period of Envisat during year 2013. The spin parameters of the spacecraft are stable within a coordinate system fixed ...

In this work, we look at the symmetry of normal modes in symmetric structures, particularly structures with cyclic symmetry. We show that normal modes of symmetric structures have different levels of symmetry, or symmetricity. One novel theoretical result of this work is that, for a ring structure with m subunits, the symmetricity of the normal modes falls into m groups of equal size, with norm...