Six stages could help mission planners choose aquanauts who are physically ready for underwater life and psychologically prepared for long periods in a sealed habitat. The proposed process first identifies serious health risks, then looks for people with the personal qualities needed to live and work with a small crew.
A peer-reviewed study published in Psychiatry Investigation describes the framework. Researchers from Soonchunhyang University and its affiliated hospitals developed the procedure after reviewing how astronauts, polar workers, divers and people in other demanding settings are selected.
The work forms part of South Korea’s Development of Underwater Space Resource Creation Technologies Project, which the Ministry of Oceans and Fisheries launched in 2022. The research team developed its criteria between October 2022 and October 2023, then asked specialists from several medical and behavioral fields to review the plan. The paper was published on March 6, 2026.
Why underwater habitats need carefully selected crews
Life inside underwater habitats places people in an environment where pressure, breathing gases, machinery and human behavior are closely linked. A health problem that would be manageable on land can become more difficult when the nearest advanced medical center is far away and returning to the surface requires a controlled procedure.
Higher pressure changes how gases act inside the body. Divers can face decompression sickness if pressure falls too quickly. Nitrogen can also affect thought and behavior at depth, while oxygen can become harmful under certain conditions. Mission planners must consider these effects alongside ordinary health needs.
Long stays add a second layer of risk. Crew members may have little privacy, limited contact with family and repeated exposure to the same people. Artificial lighting and work schedules can disturb sleep. Equipment noise may continue for hours, while bad weather or technical trouble could delay evacuation. Careful aquanaut selection aims to reduce foreseeable problems before a crew enters the habitat.
Lessons from astronauts and polar teams
The researchers reviewed selection systems used in isolated, confined and extreme environments. Space agencies offer one useful model because astronaut candidates must pass detailed medical checks, psychological evaluations and interviews before they begin training. Selection teams also examine whether applicants can make sound decisions during demanding missions.
Antarctic stations provide another close comparison. Winter crews can spend months in darkness with limited transport and few chances to leave. Their routines require cooperation among people who live beside their workplaces. Polar research has linked long periods of isolation with sleep changes, stress, lower mood and tension within groups.
Diving medicine adds the physical demands that are unique to working below the sea. The proposed aquanaut procedure combines lessons from these settings while giving added weight to pressure-related illness and emergency response. A PubMed record lists the study under aquanauts, personnel selection, underwater medicine, aptitude tests and psychometrics.
Screening out medical and mental health risks
The first half of the framework is called the select-out phase. Its purpose is to identify applicants who face a high risk of physical or psychological complications in an underwater habitat. The first three stages cover initial screening, physical examination and standardized psychological testing.
Early screening can review medical history and current treatment needs before applicants move into more expensive examinations. Physicians can then look for conditions that could affect breathing, circulation, movement, or a person’s response to pressure. Diving-related risks require special attention because some illnesses may become dangerous during descent, at depth, or during decompression.
Mental health screening considers a person’s history and current condition. Severe anxiety, unstable symptoms, poor control of impulses, or major difficulty handling stress could affect safety in a small habitat. Clinicians would interpret test results alongside interviews and medical information, which helps them build a fuller picture of each applicant.
Finding candidates suited to life underwater
Applicants who complete the early checks enter the select-in phase. The focus shifts toward identifying the people who appear best suited to the mission. Specialized assessments, personal interviews and a final combined review make up this part of the procedure.
Adaptability is central to the plan. Aquanauts may need to change duties when equipment fails, support a tired colleague and accept decisions that protect the entire habitat. Effective candidates should communicate clearly under strain and remain able to follow procedures during emergencies.
Selection also considers team performance. A crew filled with individually capable people can still experience problems when members use conflicting communication styles or respond differently to pressure. Interviews and group-based assessments may reveal how candidates settle disagreements, share work and react when a plan changes. The final decision draws on the full set of findings rather than a single score.
The six steps of aquanaut selection
The proposed six-stage process moves from broad, lower-cost screening toward detailed evaluations that require more time and specialist input. Such an order can reduce the number of applicants sent through advanced testing while keeping the early stages focused on clear medical and psychological concerns.
- Screen applications and health histories for major risk factors.
- Conduct an initial physical assessment related to general health and underwater work.
- Use psychometric tests to examine personality, symptoms, stress and thinking skills.
- Carry out specialized assessments for mission demands and crew suitability.
- Interview candidates and combine findings in a comprehensive review.
- Select the final candidates who will advance into mission training.
The first three steps belong to the select-out phase, while the final three support the select-in phase. The study’s full paper includes a diagram of the proposed route. Depending on the results, an applicant could advance, receive treatment before reconsideration, or leave the selection process.
Psychological tests for isolation and pressure
Standardized tests allow clinicians to compare candidates using the same questions and scoring rules. The study draws on established tools such as the MMPI-2-RF, which examines broad personality patterns and possible psychological symptoms. It also cites the Symptom Checklist-90-Revised and the State-Trait Anxiety Inventory.
Test results can help identify concerns that may be difficult to see during a short interview. A candidate might appear calm in conversation while reporting persistent worry, poor sleep, or unusual reactions on a longer assessment. Interviews then give clinicians a chance to ask about the setting in which those responses occur.
Sleep disruption deserves close attention because underwater residents may depend on artificial light and scheduled work periods. Poor sleep can weaken concentration and slow decisions. Over time, it can also increase irritability within a crew. Cognitive checks may help reveal whether an applicant has difficulty maintaining attention or processing information when tasks become complex.
Psychological pressure can also come from constant proximity to colleagues. Aquanauts may eat, rest and work within a limited living area. They may hear machinery throughout the day and have few opportunities for private time. Selection interviews can explore how candidates have handled earlier periods of isolation, strict routines and shared responsibility.
How the framework will be tested
The procedure remains a proposed framework that requires validation during real selection programs and underwater missions. The researchers said the general structure would be used within the Korean underwater development project, although specific operational details could not be released because of security concerns.
Future field testing could track how selected candidates perform during training and habitat simulations. Researchers could compare test results with sleep records, work performance, medical events and reports of conflict inside the crew. Such evidence would show which measures predict safe adaptation and which parts of the procedure need revision.
Selection standards must also be applied consistently. Medical thresholds should reflect the actual risks of the habitat’s depth, mission length, available treatment and evacuation plan. Psychological findings need professional interpretation because people can respond differently to tests depending on culture, language and previous experience.
The authors describe their procedure as an early practical foundation. “This proposed selection procedure offers a structured, practical framework that can be applied to missions involving underwater habitation,” the paper states. The publication record identifies the work as a 2026 study in volume 23 of Psychiatry Investigation.
Continued multidisciplinary review will be important as underwater habitats become longer lasting and more complex. Psychiatrists can examine mental health and behavior, while diving medicine specialists assess pressure-related risks. Engineers and mission planners can add information about the habitat itself, including workload, living space, rescue options and the length of isolation. Broader mission context is available from NOAA Ocean Exploration.
