How to design a space habitat that supports its residents’ mental health

In extreme environments, habitats are built for survival. Submarines, Antarctic bases, and postdisaster dwellings are designed to prioritize health and safety. This is especially the case for habitats in space, where room is at a minimum, contact with Earth is remote, and hazards are numerous.

But as humans plan for longer journeys to the moon and eventually Mars, designing habitats where crews can not only survive but also thrive will be essential to a mission’s success.

Now, engineers at MIT and elsewhere are exploring ways that habitats in extreme environments can support a person’s mental, emotional, and social wellbeing. They have assembled a resource that relates habitat design features with behavioral health outcomes such as stress, anxiety, and feelings of isolation.

Going a step further, the team has visualized these relationships in the form of an interactive online platform. Users can click through to explore connections between design and behavior, such as how a habitat’s layout affects social connection and team cohesion, and how a reconfigurable space can minimize homesickness.

“The awareness has been there for some time that living in space is difficult,” says Mich Lin, a PhD candidate in the Human Systems Lab and the Engineering Systems Lab at MIT. “We’ve come a long way from the human in a tin can. As our priorities shift toward long-duration exploration missions, making sure a crew is safe, healthy, happy, and productive becomes even more important.”

The insights that Lin’s team presents, which appear today in the journal npj Microgravity, were assembled after an extensive literature search and expert interviews. They identified many studies on habitat design and its influence on specific behaviors, such as how levels of lighting affect an astronaut’s quality of sleep. But this is the first time that anyone has brought such information together, visualizing the relationships and risks associated with a habitat’s design and an inhabitant’s wellbeing.

Lin notes that the work can be applied to designing habitats in not only space but also other extreme, isolated, and confined environments.

“Submarines, oil rigs, polar expeditions, and even refugee camps or war zones are incredibly stressful environments,” says Lin, who is the study’s lead author. “We try to make this work applicable to a lot of scenarios and identify points of intervention in habitat design to reduce stress in those extreme environments.”

The study’s co-authors include former MIT undergraduate Lu Chen and Professor Katya Arquilla of the University of Colorado at Boulder. Other key contributors to the work include Lauren Blackwell Landon at KBR/NASA, Jeffrey Montes of the space architecture firm Different Systems, and MIT undergraduate Kara Chou.

Emotional design

The researchers modeled their new design tool after a risk mapping format used by NASA. When designing a spacecraft or habitat for astronauts in space, the agency maps out the associated risks in the form of “directed acyclic graphs.” A DAG resembles a large web of relationships that illustrate how certain habitat or mission features can affect certain mission-relevant outcomes.

A typical NASA DAG depicts one-way connections between mission constraints, such as “distance from Earth,” to an astronaut’s physical health outcome, such as quality of sleep, cardiovascular impacts, cognitive function, and so forth.

“By mapping risks, we can identify points of intervention to characterize and mitigate them,” Lin explains. “NASA uses DAGs as a countermeasure to the risky business that is human spaceflight.”

The researchers looked to create a similar DAG format to map risks associated with habitat design, and less tangible behavioral health outcomes, such as stress, boredom, trust, nostalgia, curiosity, and kinship with crewmates.

“The connection between habitat and behavioral health has not been made in this format before,” Lin emphasizes. “So we made those connections for the first time.”

To do so, the team first identified habitat design factors and behavioral health outcomes that would be specifically relevant for living in extreme environments. The researchers looked to multiple resources across aerospace and human factors fields. To prioritize a human-centered perspective, they referenced the “Atlas of the Heart,” written by author, social work researcher, and University of Houston Professor Brené Brown. In the book, Brown identifies 87 emotions and experiences that define what makes us human.

“From there, we did a down-selection of which emotions would be the most impactful in our scenario of habitat design in extreme environments,” Lin explains.

The team zeroed in on 14 main emotions or experiences that they considered behavioral outcomes that could be influenced by habitats in extreme environments. These include anxiety, autonomy, nostalgia, curiosity, fatigue, and kinship.

They then carried out a wide-ranging search through the scientific literature to identify studies relating to habitability in extreme environments. For instance, NASA has carried out extensive research on the effects of lighting on sleep, the resetting of circadian rhythms, and productivity. Other studies have investigated circulation and habitat layout and their effects on privacy, social connection, and crew performance.

Lin and their colleagues assembled connections and conclusions from numerous studies to create a DAG, or a web of habitat design features, and their downstream effects on aspects of mental, emotional, and social wellbeing. They also solicited feedback from experts across industry, academia, and NASA to evaluate and strengthen the DAG.

They then developed an online platform, dubbed the Human-Environment Connection and Interaction Atlas, or HECIA, as an interactive tool for habitat designers.

Click and connect

When using the atlas, the team envisions that designers can take either a forward or backward approach. The atlas lays out habitat design elements, and their downstream behavioral connections, in roughly the order in which decisions are made in designing a mission.

For instance, in designing a spacecraft to journey to Mars, a designer might take a forward approach, and first click on a feature associated with an early design stage, such as “distance from Earth,” knowing that this would be a significant consideration. The atlas would automatically display risks associated with being far from Earth, such as limits to resources such as “food,” “medical capability,” and “family and friends,” and to behavioral health outcomes such as “nostalgia/homesickness.”

A designer could then take a backward approach. If, for instance, they want to prioritize minimizing nostalgia/homesickness, they could click on the term to reveal design features and ideas that affect and could potentially improve it, such as in this case, “place attachment,” or feeling emotionally attached to a place. Clicking on this term would in turn reveal upstream elements such as “reconfigurability” and “privacy” — design elements that could be put in place to encourate place attachment, and reduce homesickness.

For every term that a designer clicks on, Lin and their colleagues provide a summary, based on empirical research, that explains both the term in the context of extreme habitats, and provides examples of design interventions. For instance, a designer who is looking for ideas to minimize social isolation on long-duration missions may click on the term, to reveal a description.

“They may read that research has found ‘access paths, stairs, entrances, contribute to the formation of friendships and social cohesion,’” Lin offers. “So that would give them an idea of connecting public spaces in the habitat, via the private spaces, so people have to mingle, essentially.”

They emphasize that the new platform and the ideas informing it are not a one-size-fits-all for how to design any extreme habitat. That depends on a particular habitat’s specifications and constraints.

“Rather, this helps you think about connections that might be important, but that aren’t immediately obvious,” Lin says. “As we envision truly becoming an off-planet species, or creating places we want to live in in space, there is so much potential for us to reimagine habitats that make us happy and productive.”

This research was supported, in part, by NASA.