Engineering activities often emphasize the practices of engineers, but pay less attention to aspects of the nature of engineering. One important aspect of the nature of engineering is an understanding of the aims and values that underlie engineers’ decision-making. This activity helps students develop an understanding of the role of aims and values in engineering through an activity wherein students design and test a wheel for a Mars rover. In addition to providing opportunities to discuss the role of aims and values in engineering, the activity also targets MS-ETS1-1: Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions.