Radiometric propulsion for sun-powered near-space aircraft: Advancing with order-of-magnitude enhancement through graphene aerogel-coated vanes

Radiometer is a light-induced propulsive device in the rarefied gas environment, which holds great potential for next-gen near-space flight. However, its practical applications are hindered by the weak propulsion forces produced on the conventional radiometer vanes. Herein, this 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 (10⁻⁴–10² Pa). Direct simulation Monte Carlo calculations reveal that the outstanding performance is ascribed to the improved temperature difference and gas–solid momentum transfer efficiency tailored by surface porous microstructures. Moreover, we demonstrate a stable and long-term levitation with the graphene aerogel-coated model in both 1 sun irradiation and a rarefied gas environment.