Objective Depression can present a significant threat to long-duration space missions, and crews need the ability to recognize it and treat it effectively. We are developing a prototype computer-based system that includes a module for the recognition and treatment of depression. Before being used by astronauts, this system needs to be further developed and tested for efficacy in an analog population. The countermeasure we are developing is intended for use both in pre-flight training and on the International Space Station. The program has substantial Earth benefits.