I. Introduction stronauts can experience a number of in-flight life-threatening emergencies aboard the International Space Station (ISS), including decompression, fire, and toxic spills (eg, ammonium leaks). 1 Although these emergencies are rare, several incidents have occurred in space operations. On February 24, 1997, a Vika chemical oxygen generator malfunctioned aboard the Mir space station and caused a severe fire. Large amounts of toxic smoke filled the station for 45 minutes with near zero visibility. 2 During a June 24, 1997 docking test of the Progress M-34 cargo vehicle, the M-34 collided with Mir causing decompression throughout the station and resulting in the need for permanently sealing the damaged Spektr module. 3 On the ISS, astronauts have also experienced a number of false fire alarms, including a false ammonium alarm in 2014 that resulted in the crew temporarily moving to the Russian side of the station. 4, 5

Not surprisingly, procedures training is of critical importance when preparing astronauts for the inherent risks in spaceflight. However, significant training challenges exist both on the ground as well as in space. Training astronauts requires a considerable amount of resources. And after training, it is often difficult to assess an astronaut’s ability to cope with the physiological and psychological stresses evoked by a life threatening situation. Stress inoculation training (SIT) can potentially help astronauts build resilience to adverse experiences. As inoculation implies, SIT exposes individuals to minor stressors that can enhance resistance to stress. 6 Stress arises in transactional situations where the individual’s perceived demands tax or exceed the perceived coping resources, which can result in physiological, psychological, behavioral, or social outcomes. 7 From this transactional perspective, stress is a coupled relationship between the person and the environment. Therefore, psychosocial stressors cannot directly “cause” the stress response, but the extent to which they are stressful is a function of the individual’s cognitive appraisal of the situation. This coupling presents an avenue for SIT to train coping skills which prepare the individual to respond more favorably to negative stress events. Implementation of stress training can differ based on the nature of the stressor (eg, acute or chronic) and the coping abilities of the individual. A main tenant of SIT, often called exposure training, is practicing stress coping skills over a series of sessions with gradually increasing levels of stressors until realistic stress levels have been achieved. Virtual reality simulations offer a practical venue to control stress levels and expose astronauts to realistic scenarios.