Grid fin

Grid fins (or lattice fins) are a type of flight control surface used on rockets and bombs, sometimes in place of more conventional control surfaces, such as planar fins. They have been used since the 1970s in various Soviet ballistic missile designs such as the SS-12 Scaleboard, SS-20 Saber, SS-21 Scarab, SS-23 Spider, and SS-25 Sickle, as well as the N-1 (the intended rocket for the Soviet moon program).