The SCORPION (Self CORrecting Projectile for Infantry OperatioN) program was a research initiative funded by the U.S. Defense Advanced Research Projects Agency (DARPA) and led by the U.S. Army Research Laboratory (ARL) and the Georgia Institute of Technology to integrate micro adaptive flow control (MAFC) technology into small caliber munitions to develop spinning, guided projectiles. The program led to the creation of a spin-stabilized 40 mm grenade, also called SCORPION, that could propel itself to its target by using calculated micro-jet bursts of air to correct its path once launched.
History
The SCORPION program began in 2001 as a joint venture between DARPA, ARL's Weapons and Materials Research Directorate (WMRD), Georgia Tech's Departments of Mechanical Engineering, Electronic and Computer Engineering, and Aerospace Engineering, and Georgia Tech Research Institute's Aerospace, Transportation, and Advanced Systems Laboratory in order to improve the precision of small to medium-sized munitions in complex, dynamic environments. It was guided by the U.S. Army's goals to develop low-cost, smart munitions that could more accurately hit its intended target. In particular, the Army was seeking to produce a new generation of autonomous 20 mm to 40 mm gun-launched projectiles that could correct its course mid-flight. Doing so would increase the capabilities of infantry units as well as decrease the weight of munitions that soldiers would have to carry.
Micro adaptive flow control is largely defined by the active manipulation of aerodynamic flows using small time-dependent actuators in carefully chosen locations. By taking advantage of flow instabilities, the system can generate large amounts of energy from using only a small fraction of the overall flow if the actuators and their activity are properly assigned. As a result, MAFC can enable low power yet highly distributed redundant actuation systems in contrast to flow systems that utilize steady blowing where high velocity flows must be provided through complex and high-loss ducting. Rather than configuring the shape of the munition with fins or canards to control its trajectory, the SCORPION project aimed to integrate these tiny actuators on the munition that pump out brief spurts of air at a high frequency (around 1000 Hz). By emitting these bursts of air for just a few milliseconds at a time, these small synthetic micro-jet actuators were capable of modifying the projectile's flow characteristics and pressure distributions. In short, the jets of air were able to steer the munition by creating an asymmetry in the airflow surrounding the projectile, producing a strong enough force to affect its trajectory largely due to the Coanda effect.
Development
The SCORPION program was divided into two phases, Phase I and Phase II. The former focused on constructing the flight control system and determining whether MAFC could be integrated into a 40 mm round to provide adequate guidance to its target, while the latter prioritized determining whether MAFC technology could be used to steer projectiles that were smaller and even faster than those used in Phase I. By 2005, Phase I had been completed, and the SCORPION program was chosen as a DARPA demonstration program in order to further investigate the use of MAFC in high-velocity, small-diameter projectiles. The SCORPION program concluded in 2007 after successfully demonstrating the use of MCFA to maneuver a 40 mm rifle-launched grenade.