Predicting the motion of wheeled robots in unstructured environments is one of the most challenging applications of multibody system dynamics. The study of extraterrestrial exploration rovers on soft terrain introduces the additional need to consider the effect of non-terrestrial gravitational acceleration on the forces and torques developed at the wheel/terrain interface. Simply reducing the wheel load under earth gravity overestimates the travel distance and predicts better performance than is actually observed in reduced-gravity measurements.In this work, we put forward a research methodology to determine the effect of reduced gravity on wheel/terrain interaction. Elastoplasticitybased models are used to determine wheel/terrain interaction forces and torques; these models rely on the assumption of a certain velocity profile of the soil under the wheel. Experiments were conducted to assess the effect of reduced gravity on this velocity profile, as well as on the traction force and sinkage developed by the wheel. The present contribution reports ongoing developments of this research.