Radiometric propulsion: Advancing with the order-of-magnitude enhancement through graphene aerogel-coated vanes

Abstract

Radiometer is a light-induced aerodynamic propulsive device under the rarefied gas environment, which holds great potential for the next-gen near-space flight. However, its practical applications are hindered by the weak propulsion forces on the conventional radiometer vanes. Herein, this material-aerodynamics cross-disciplinary study develops novel radiometer vanes with graphene aerogel coatings, which for the first time realize an order of magnitude enhancement in radiometric propulsion. The improvement is manifested as up to 29.7 times faster rotation speed at a low pressure of 0.2 Pa, 13.8 times faster at the pressure (1.5 Pa) with maximum speeds, and 4 orders of magnitude broader operating pressure range (10E-4 - 10E2 Pa). Direct Simulation Monte Carlo calculations reveal that the outstanding performance is ascribed to the improved temperature gradient and gas-solid momentum transfer efficiency tailored by surface porous microstructures. Moreover, we demonstrate a stable and long-term levitation prototype under both 1 sun irradiation and a rarefied gas environment.