Processes in the interior of planetary bodies cause the formation of tectonic structures like orogenic belts and graben. The structures we see today reflect the physical properties of the lithosphere at the time of their formation and their analysis gives us clues to the evolution of the planetary lithosphere. Examples for surface deformations caused by tectonic processes may be found in the whole solar system: The surfaces of the Moon and Mercury are abundant in compressive structures, Mars and Venus show additional extensional features and the surfaces of the icy moons in the outer solar system are also covered by them. However, the processes responsible for the deformations may vary considerably. The simulations therefore always have to take into account the peculiarities of the bodies considered.The dataTectonic structures may be identified using image data, which is available for many moons and planets in high quality. The physical modeling additionally requires topographic information, which can be extracted from the images using, e.g. stereographic reconstruction. Global digital elevation models, which have been produced using specialized instruments on board satellite missions, have been obtained for the Earth, Venus, the Moon and Mars. A topographic model of Mercury will be compiled from the data that will be collected by the NASA Messenger Mission, which was launched in 2004. Numerical simulations We simulate the formation of tectonic structures using one and two dimensional structural mechanics models, applying half-analytical and finite element techniques. The models are then compared to the actual topography to determine the elastic properties of the lithosphere. It is thus possible to look beneath the surface and into the past of the planetary body considered and gain information about the physical properties of its lithosphere. Since the latter are strongly temperature depended, the collected data allows us to gain insight into the thermal evolution of the planet.