This paper presents a safe control applied to a reaction wheel pendulum. assuring that the system satisfies stability objectives and safety constraints. Safety constraints are specified in terms of a set invariance and verified through control barrier functions (CBFs). The existence of a CBF satisfying specific conditions implies set invariance. https://www.roneverhart.com/1915-Old-Taylor-Bourbon-Bottled-1933-Prohibition-Bottling-Quart-low-fill/