A distinctive and challenging aspect of astronaut training is that astronauts must be fully functional crew members on their first flight, unlike the case in other safety-critical domains that have some measure of on-the-job training or which purposefully provide training by incrementally increasing duties within an operational environment. Thus astronaut training must be sufficient to meet all of the training requirements identified throughout this report.
The first training requirement is that astronauts be ready to perform specific, isolated tasks, and the second training requirement is that the depth of understanding required for each task be deliberately identified and established. The NASA Mission Operations Directorate currently has a task analysis methodology that is used to define tasks and to classify each task for each crew member according to whether the crew member will be a user, an operator, or a specialist; these classifications are then considered in the development of training facilities.
For the purposes of highlighting training methods, a more formal categorization is the Skills, Rules, Knowledge Framework offered by Rasmussen.1
A knowledge-based behavior involves reasoning about the situation based on abstract knowledge of the situation and the available courses of action. This level of behavior is generally the first to be learned, and can be taught through training methods that focus on abstract reasoning, which includes classroom instruction and self-study. Thus, tasks which only need to be trained to this level do not require any unusual facilities or novel training methods.
A rule-based behavior relates the immediate situation to rules and procedures. This type of behavior is sensitive to correctly recognizing the salient features of the immediate situation. Thus, training an astronaut to this type of behavior at a particular task requires experience in an environment sharing many of the relevant stimuli. For example, if astronauts are expected, after training, to be able to execute a robotics operation procedure, their training needs to be conducted in a facility that emulates the important dynamics of the operation, and simulates the important cues that correspond to each step in the procedure.
A skill-based behavior is possible only with the greatest training, training in the most accurate emulations of the operational environment, and recent training. This type of behavior requires very little or no conscious control to perform or execute an action and is indicative of sensorimotor behaviors (in which the astronaut can smoothly sense relevant patterns in the environment and relate them to their required motor inputs) and of naturalistic decision making (also called recognition-primed or intuitive decision making). The most skilled behavior can be trained when the training facility closely emulates a wide range of aspects of the situation, but the skill will generalize to other tasks
1 J. Rasmussen, Skills, rules, knowledge; signals, signs, and symbols, and other distinctions in human performance models, IEEE Transactions on Systems, Man, and Cybernetics13:257-266, 1983.
requiring similar sensorimotor behaviors. Because these types of behavior allow for immediate and reliable responses, this depth of learning is particularly important to tasks resolving emergencies and to time-critical, safety-critical tasks.
Thus methods for training individual astronauts on specific tasks need to be tailored to the depth of knowledge expected for each task. For training to knowledge-based behaviors, classroom instruction and self-study are common. For rule-based behaviors, a mock-up or part-task simulation needs to emulate the key dynamics of the operation such that the astronaut can be expected to recognize the triggers of specific rules, identify the systems and controls to act on in order to execute the required steps, and then monitor the results to make sure that these steps are successful in terms of system response to their actions. Thus a mock-up or part-task simulation could be as simple as a computer simulation of the most important systems with similar controls, surrounded by a cardboard schematic of the surrounding environment.
Skill-based training requires the greatest-fidelity, highest-cost facilities. The NASA Neutral Buoyancy Laboratory, for example, is used in extravehicular activity (EVA) training; it situates the astronauts in a perceptibly risky environment so that they experience the discomfort and limited movement of a real space suit, and it strives to provide a realistic representation of International Space Station components such that the astronauts can quickly recognize important features from multiple perspectives.
Some industries, such as commercial aviation, have a significant population to train and have used an economy of scale to streamline training systematically. For example, airline pilots are first trained and tested on a range of knowledge-based behaviors in a ground school. Then, in training and testing on rule-based behaviors, the airline pilots move through a series of part-task simulators and cockpit mock-ups—these range from cardboard mockups of the entire cockpit (in which pilots are expected to learn the position of each cockpit control to the level of being able to reach each control with their eyes closed); to emulators of specific systems that they can run on their personal computers, imitating a system’s operation by clicking the mouse on pictures of the correct buttons on the computer screen; to fairly complete mock-ups of the entire cockpit but without motion, sound, or the view out the window. Only when these knowledge- and rule-based behaviors are demonstrated do airline pilots move to the most advanced, highest-fidelity “Level-D” flight simulators. These simulators, according to Federal Aviation Administration regulations, must fit an extensive list of specific capabilities, including a full emulation of the cockpit in which all of the controls look and act exactly the same as those of the actual aircraft. These highest-fidelity simulators are associated with significant acquisition costs ($5 million to $20 million for established production systems) and operational costs (hundreds of dollars per hour), require specialized infrastructure (e.g., significant electrical power, reinforced concrete floors), and must be maintained by specialized personnel. The required use of these facilities is systematically justified through established, regulated methods for analyzing required tasks and their depth of understanding (such as the Advanced Qualification Program). Such training programs also monitor individual progression through the process in order to tailor training protocols to maximize both learning and cost-effectiveness, while routinely evaluating overall program efficacy and cost-effectiveness.
Many training environments, including those for the Astronaut Corps, do not have an economy of scale that warrants the acquisition and maintenance of a wide range of simulators of varying fidelity. Knowledge-based and rule-based behaviors can be learned in high-fidelity simulators, but skill-based behaviors cannot be learned in low-fidelity simulators or classrooms. Thus the need for the highest-fidelity training facilities is paramount, as smaller training operations must maintain high-fidelity training facilities and, for maximal cost-effectiveness, fully utilize them. Additionally, these facilities can eliminate any cheaper, lower-fidelity simulations, for which the trainees can instead train within the availability of higher-fidelity simulations.
A third training requirement is the need to develop teamwork skills in general and to execute these skills within a specific operational culture. These teamwork skills are largely assumed in astronaut training to emerge as a byproduct of simultaneously training multiple individuals together (i.e., without formal teamwork training), although in other domains including commercial aviation, team training, such as crew resource management training, has become far more formalized than it is in astronaut training. Research suggests that team training interventions are a viable approach for enhancing team outcomes. Such training approaches are useful for improving cognitive outcomes, affective outcomes, teamwork processes, and performance outcomes. Moreover, results suggest that
training content, team membership stability, and team size moderate the effectiveness of team training interventions. One function of this training is to establish a common operational culture that shares the same vernacular, reinforces team bonds, and establishes shared goals for performance and safety.
Finally, perhaps the least tangible aspect of training addresses the meta-cognitive, or executive, functions that astronauts must perform as part of their “cognitive control” while under stress. In their study of stress and human performance, Salas, Driskell, and Hughes define stress as the process by which certain environmental demands evoke an appraisal process in which perceived demand exceeds resources, and the result is undesirable psychological, physiological, or behavioral outcomes; for example, stress-related failures of decision making have been attributed to nearly half of fatal aviation accidents.2 At a basic level, training for cognitive control and effective stress response is related to the development of executive functions that guide selective attention to appropriate aspects of the environment—such as pilots learning, when disoriented, to focus on a visual scan of flight instruments despite conflicting vestibular sensations. At a more holistic level, an expert is able to plan and pattern activities to avoid “cognitive lockup,” to manage tasks effectively within given demands and resources, and to recognize effective decision-making strategies to apply to different types of situations.
Recent research suggests that three elements must be considered in training for effective cognitive control (including decision making) under stress. First, such training is most effective when the trainees enter actual operations with the perception that they are well prepared. Second, training theories suggest that the trainee should be trained on tasks and situations similar to those that will be experienced under stress, an effect referred to in the military as “train how you fight.” Third, training for stressful tasks requires a stressful training environment.
The need for a stressful, operationally realistic training environment is also recognized operationally by safety-critical domains. For example, although commercial aviation often certifies its pilots on the basis of training in simulators alone, this industry also recognizes the need for a newly minted pilot then to fly real operations with a more experienced pilot for a significant portion of time as the new pilot develops further experience with the real operational environment.
Similarly, while military training increasingly uses simulators, live-fire exercises remain a vital component of training. For example, a review of the significant losses experienced by flight pilots in their first experiences of real combat motivated the ongoing U.S. Air Force Red Flag exercises, which re-create as realistically as possible the actual stresses of the real flight environment. Similarly, training for naval nuclear operations, for example, progresses from classroom and part-task simulator instruction through the training on actual nuclear power plants dedicated to training and providing the same hazards as those of real plants.
If one determines that a stressful training environment is necessary, in which environment should astronaut training be conducted? Historically, the operational culture of the Astronaut Corps has been centered on aviation, including its attention to safety and its valuing of teamwork and calm, systematic responses to emergencies. Bearing in mind that changing an operational culture is difficult and that the period of transition is a risk factor during which common safety nets within the organization are stressed, changing the Astronaut Corps training basis from aviation would be a significant, risky endeavor that should only be undertaken when there is a compelling reason.
Thus, the ideal training for the Astronaut Corps should be designed to integrate instructional content, instructional method, and training resources systematically and purposefully in a phased progression from classroom instruction, through simple procedural trainers (part-task simulators, mock-ups), through high-fidelity simulators, and ultimately into stressful training environments that foster an effective operational culture and which require response to stresses like those that may be experienced in spaceflight. For an Astronaut Corps using aviation as its shared operational experience, this ideal training environment would then include procedural trainers and simulators of spacecraft, and then, because the spacecraft are themselves unavailable for training, a transition to aviation environments that mirror the time pressure and physical stressors of spaceflight, including the discomforts of specialized suits, helmets, oxygen masks, and life-critical environmental support systems.
Even though ideal, such a full range of low- and high-fidelity simulators and aircraft as noted in the ultimate
2 E. Salas, J.E. Driskell, and S. Hughes, Introduction: The study of stress and human performance, pp. 1-45 in Stress and Human Performance(E. Salas, and J.E. Driskell, eds.), Lawrence Erlbaum Associates, Inc., Mahwah, N.J., 1996.
training environment described above would be prohibitively expensive within current and foreseen budgets. The acquisition costs of specialized simulators, for example, would be significant. However, as noted throughout this appendix, the most important tasks must be trained to the level of skill-based behavior and to the extent that the astronauts can apply effective stress responses, and this requires training in real, stressful environments. Thus, sufficient training cannot be provided only in cheaper, low-fidelity simulations or classroom environments.