The compact fNIRS system proposed will enable flight simulator and other field testing. Currently no commercial product exists to measure cognitive state in the field, work in this area has been experimental using rack mounted equipment in a lab environment. Successful development of a compact fNIRS cognitive state monitor would enable an innovative early warning system during long duration missions, with both space and aeronautics applications. Spaceflight applications include detecting and preventing vigilance decrements due to the effects of microgravity: motion sickness, lack of sleep, loss of sensorimotor control, increased stress or mood changes. Commercially this technology is applicable to any human in the loop system requiring improved attentional performance. Commercial pilots deal with many stressors that can compromise cognitive ability: fatigue, uncomfortable levels of noise, heat, vibration, and mental workload. Use of CSM may be able to avoid mistakes by pilots and other safety critical personnel such as air traffic controllers.