In addition to monitoring the behavioral health of the crew during space missions, the proposed device can be used to diagnose and treat various neurologic diseases and psychiatric illnesses. The device, for the first time, allows ambulatory, dual-modality functional imaging of cortical activity. The system can be designed as ambulatory units for use primarily in home settings as well as stationary units for use primarily in clinical settings. Crewmembers on long Exploration missions must remain productive in confined and crowed environments in which workloads are heavy, sleep is difficult, and where there is isolation from family and friends. Developing methods that allow crewmembers to deal with stress and other psychological challenges of long voyages will be critical to successful missions. The proposed neurodiagnostic device can be used to monitor levels of stress as well as the general psychological health of the crew during Exploration missions. The device can also be used to measure the degree of mental workload during performance of complex and cognitively challenging tasks and can be used to design and optimize the tasks. The low mass and low power consumption required for the wearability of the device are also key factors for space applications as launch costs are directly determined by mass and volume.