This work presents the advancements in the development of simulation models of spacecraft components as part of a testbench for verification of onboard flight software. The satellite and its mission are briefly described as to give an idea of the conditions where the simulation has to run. The simulation environment, SimTG, is also introduced and a description of the developed models is presented. The models required interaction between different simulation environments, real hardware and simulated hardware, and also some data processing was necessary in order to filter undesired information. Finally, the performance of the models was tested and verified and a sensible improvement of the state of the testbench on the simulation side was achieved, although a considerable amount of work still lies ahead before a complete onboard software verification tool is ready.