There is a category of psychological research that gets discussed in two largely separate literatures, even though the people doing the research are looking at the same conditions in two different uniforms. The psychology of long-duration spaceflight and the psychology of submarine deployment both belong to what is now called, in the academic literature, the study of Isolated and Confined Extreme environments, or ICE. The shorthand covers polar wintering stations, deep-sea diving operations, simulated Mars habitats, and several other categories besides. Within ICE, two institutions have spent the better part of half a century managing the problem at scale: the Navy Submarine Services and the National Space Programmes.
What they have arrived at, on examination, is not the same response.
It is almost the opposite response.
The most useful synthesis of the underlying conditions is in the 2021 review by Lawrence Palinkas and Peter Suedfeld in Neuroscience and Biobehavioral Reviews, which surveys the ICE literature across polar, submarine, and spaceflight settings. The same set of stressors recur across all three: separation from family, forced cohabitation with a small unchanging group, sleep disruption from the loss of natural day-night cues, monotony, the absence of physical privacy, and the inability to leave when the situation becomes difficult. The Palinkas paper is careful to note that these conditions do not inherently produce performance decrements. People can adapt to ICE environments without obvious difficulty. The institutions selecting and managing them, however, have to make decisions about how that adaptation gets supported. Submarines and space programmes have made those decisions differently.
The model the submarine services have built
The submarine model, considered as an institutional response to confinement, is largely about structure. The crew is selected for fit with the operational role rather than for psychological resilience as such. According to a recent essay by a former Royal Navy submarine officer published by the British American Security Information Council, who served as second-in-command of a Resolution-class Polaris-missile submarine and joined the service sixty years ago, Royal Navy submariners undergo no equivalent of the astronaut psychological selection process. The US Navy uses some screening, but its emphasis is on aptitude and the absence of disqualifying conditions, not on the cultivation of a particular psychological profile. A 1999 study by Gro Sandal and colleagues at the University of Bergen, published in Military Psychology and still the canonical reference, found that the best predictors of coping during submarine missions were interpersonal orientation, achievement motivation, and habitual problem-directed coping styles. These are not traits the navy actively cultivates. They are traits the navy filters for, broadly, then trains around.
Once at sea, the model is one of role mastery and severe communication restriction. A submarine on a ballistic-missile deterrent patrol receives no real-time external communication, by design, because broadcasting would defeat the boat’s reason for being there. The personal contact a submariner gets from home is a familygram, a one-way text message of roughly 50 words, screened before delivery, sent at most once a week. There are no windows. There is no day or night except the one the ship’s lighting suggests. Bad news from home is held by the captain at his discretion until the patrol is nearly over.
The cultural texture of this is well-documented in the navy literature. The crew member’s job is to qualify on the systems, master the procedures, and become a working part of the boat. The inner life is the crew member’s own private business. Problems that cannot be contained are routed through the chain of command, not through a therapist. Stoicism is not framed as a value. It is structural.
The model the space programmes have built
The astronaut model, considered as an institutional response to the same conditions, is almost the inverse. Selection is heavily psychological. Candidates are screened across multiple personality inventories, simulated mission environments, interpersonal observations, and team performance tasks. The ‘right stuff’ framing, as Nick Kanas and Dietrich Manzey describe it in their 2008 book Space Psychology and Psychiatry, has been refined over decades into a specific psychological profile that emphasises emotional stability, communication openness, and the capacity for what the literature calls active coping.
Once in flight, the model is one of sustained psychological countermeasure. Astronauts on the International Space Station receive scheduled private conferences with flight surgeons and behavioural specialists. They are given crew care packages with personal items selected by family. They have real-time email and video contact with people on the ground. The Cupola observation module, added in 2010 primarily for operational viewing of robotic and docking activities, has been described in both NASA and ESA materials as also providing psychological benefit to the crew, consistent with a broader literature on Earth observation as one of the more reliable mood elevators in long-duration spaceflight. There are formal lessons-learned debriefs after every mission. There is an extensive post-flight readaptation programme.
The cultural texture is the opposite of the submarine one. The astronaut’s inner life is not private business. It is mission-critical infrastructure, monitored and supported in something close to real time, with explicit institutional permission to be articulated to others. Where the submarine services compress the inner experience behind the role, the space programmes extend the role to include the active management of the inner experience.
What the two communities seem to have learned, in opposite directions
The interesting question is not which model is right. Both are reasonably effective for their actual missions. The submarine model has produced workable patrols for sixty years across navies whose nuclear deterrent depends on the crew getting through. The space-station model has produced sustained habitation in low Earth orbit for more than twenty-five years. What is interesting is what each model implies about what isolation actually is.
The submarine model implies that the inner experience of confinement, if left alone, will largely take care of itself, provided the structural conditions are right. The selection process keeps out the people for whom this is not true. The communication restrictions remove an entire category of distraction. The role provides constant external focus. The cultural agreement that nobody is going to ask you about your feelings is, in this model, a kindness. The submariner is not being denied psychological support. The submariner is being granted the dignity of having the inner life remain private.
The astronaut model implies the opposite. It assumes that without active management, the inner life under confinement will not take care of itself. It assumes that the same conditions submarines treat as background will, for a six-month ISS mission or a longer transit to Mars, generate problems that have to be addressed in flight. It assumes the failure mode is internal and that the institution has to reach into the crew member’s experience and help maintain it.
Neither model is making a claim about human nature in general. Each is making a claim about what their particular mission requires, given their particular crew, for their particular duration. Taken together, however, the two models suggest that isolation is not one thing. It is at least two, which respond to opposite interventions.
What we are left with, in our reading of the two literatures side by side, is a quieter point than the popular framing of either tends to admit. Confinement does not have a single psychological signature. It has at least two: one for the case where the inner experience can be contained by the role, and one for the case where the role cannot contain it. The submarine services have built the institution around the first. The space programmes have built theirs around the second.
What neither has resolved, and what may not be resolvable from within either, is which model the longer missions ahead will actually need.
