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 were developed in the 1950s by a team led by and 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). In Russia, they are thus often referred to as grid fins. Grid fins have also been used on conventional missiles and bombs such as the Vympel R-77 air-to-air missile; the 3M-54 Klub (SS-N-27 Sizzler) family of cruise missiles; and the American Massive Ordnance Air Blast (MOAB) large-yield conventional bomb, and on specialized devices such as the Quick-MEDS delivery system and as part of the launch escape system for the Soyuz spacecraft. In 2014, SpaceX tested grid fins on a first-stage demonstration test vehicle of its reusable Falcon 9 rocket, and on December 21, 2015 they were used during the high-velocity atmospheric portion of the reentry to help guide a commercial Falcon 9 first stage back to land for the first successful orbital booster landing in spaceflight history. The 1st stage of the private Chinese company i-Space's Hyperbola-1 rocket appeared on July 25, 2019 to be equipped with steerable grid fins for attitude control. On July 25, 2019, China launched a modified version of Long March 2C which featured grid fins atop the first stage for controlled re-entry of the spent rocket stage away from people in nearby towns and cities. Design characteristics Conventional planar control fins are shaped like miniature wings. By contrast, grid fins are a lattice of smaller aerodynamic surfaces arranged within a box. Their appearance has sometimes led them to be compared to potato mashers or waffle irons. Grid fins can be folded, pitched forward (or backwards), against the cylindrical body of a missile more directly and compactly than planar fins, allowing for more compact storage of the weapon; this is of importance where weapons are launched from a tube or for craft which store weapons in internal bays, such as stealth aircraft. Generally, the grid fins pitch forward/backward away from the body shortly after the missile has cleared the firing craft. Grid fins have a much shorter chord (the distance between leading and trailing edge of the surface)