Modafinil was used by the French Foreign Legion, U.S. Air Force, and U.S. Marine infantry during the Gulf War to enhance "operational tempo" (a term that denotes the speed and intensity at which military operations or activities are executed), aiming to optimize the overall performance and efficiency of the unit.
Armed forces in various countries, including the United States, the United Kingdom, India, and France, have considered modafinil as an alternative to traditional amphetamines for managing sleep deprivation in combat or extended missions. The US military approved modafinil for specific Air Force missions, replacing amphetamines for fatigue management. The use of modafinil in military contexts without sleep deprivation is not recommended due to inconclusive evidence on its cognitive enhancement benefits and potential risks of adverse effects.
Modafinil is also available to astronauts aboard the International Space Station for the management of fatigue caused by circadian dyssynchrony in orbit.