# Manipulating Stress Responses during Spaceflight Training with Virtual Stressors
## 3 Environment Design  
To inform how stressors in VR should be designed, a workshop was held with a panel of subject matter experts to identify stressors that contribute to the stress in a spaceflight environment. Subject matter experts have been used in previous research to identify environmental stressors (e.g., noise, radiation) in a disabled submarine scenario [41]. Attending experts included a retired U.S. NASA astronaut, a retired NASA ISS flight director, and three experts on psychological and physiological stress. The panel was presented with existing ISS emergency fire procedures and layouts of the ISS [42]. The panel identified a series of potential stressors, how they are mapped onto the emergency response procedures, and what effects the stressors might have on astronauts. Each stressor's intensity was rated on how the subject was likely to feel, and what the effects on performance will be. In addition, it was assumed that certain stressors would increase stress levels without influencing task-based workload, so the stressors were categorized into task-related and environment-related stressors. In other words, the stressors during an emergency fire were categorized by their ability to change the environment without substantially changing how the individual would perform the procedure. A list of stressors was compiled by the panel (Table 1). These stressors are related to an emergency fire procedure, and therefore may exclude peripheral stressors previously identified by subject-matter experts that may be associate with deep-space missions [43]. The stressors were categorized by the type of stress induction, manipulation type (environment or task manipulation), within or between experimental comparison. The process of categorizing environmental stressors was similar to the method proposed by [41]. Stressor levels and potential deviations from the selected emergency procedure were also listed. Three environmental stressors were selected for use in the study and the stressor intensity was varied among training scenarios: alarms, flickering lights, and degraded visibility from smoke. Priority was given to stressor manipulations that did not affect tasks requirements, to avoid later confounds in experimental design. The goal was to increase stress while keeping the task requirements the same to allow direct comparisons of stress training with and without stressor manipulation. By using only environmental stressors and not task stressors, any changes from such a comparison would not be confounded by differences in task requirements. For example, intensity of noise and visible smoke may be stressful, but will not change the task procedure for locating and extinguishing a fire. The selected stressors were then used to establish three stressor levels of low, medium, and high during the VR training scenarios. A few of the task stressors (e.g., rising atmospheric contaminants) were included in all the training scenarios to distribute task load equally. \begin{table}
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\begin{tabular}{c} Task Difficulty, \\ Time pressure \\ \end{tabular} & Linear & Task, Envir. & Within \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Stressors Identified from ISS Emergency Fire Procedure. The panel then developed a simplified fire procedure for trainees to follow. A flowchart of the selected emergency procedure that could be used for laboratory experiments is illustrated in Figure 1. This procedure was modified from the existing ISS Emergency Procedures [42] by shortening the duration of the procedure down to 5-10 min, eliminating communication with Mission Control Center (MCC) and crewmember induced stressors, having the smoke alarm indicate the presence of a fire (as opposed to being a false alarm), and minimizing tangential procedure steps that do not directly help the trainee locate the  
\begin{table}
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fire source. This procedure is also like the ISS fire strategy created by [18] for the purpose of task training.