378 Days Later: Navy Scientist Reflects on Testing NASA's Mars-Like Habitat

In order to know how human life can adapt to a foreign environment like Mars, we first have to replicate those conditions on Earth.

On June 25, 2023, four NASA volunteers entered a habitat at Johnson Space Center in Houston to simulate life on the red planet.

For more than a year, they stayed inside that isolated environment, conducting research and simulating experiments to inform future expeditions to Mars.

NASA's Crew Health and Performance Exploration Analog mission - CHAPEA in short - was the first of three planned Mars simulations. Mission 1 lasted 378 days inside the Mars Dune Alpha habitat, a sealed-off, 1,700-square-foot, 3D-printed building that had private crew's quarters, two bathrooms and a kitchen, as well as areas for medical, recreation and fitness activities, and growing crops. There was also a technical area where the crew worked in conditions closely replicating those found on Mars.

Navy Lt. Anca Selariu, a microbiologist with Naval Medical Research Unit San Antonio, was one of the volunteers who completed the mission in July. A native of Romania, she moved to the U.S. decades ago and has been in the Navy for about five years.

"It still seems like a dream that I got to be one of the first crew members to complete a full mission," she said via email shortly before exiting the Mars Dune Alpha habitat.

Selariu brought expert knowledge on vaccines, prion transmission, gene therapy and infectious diseases to the mission. While she couldn't go into much detail about the crew's experiments and data findings, she said they had many technical hurdles to address, with the human elements being one of the most challenging.

"Mars is not a place we can send a rapid response team to if anything goes wrong, so we cannot afford to leave [Earth] unprepared," Selariu said. "We're helping NASA in formulating various countermeasures to address the combination of physical and psychological stressors caused by isolation, resource limitations, communication delays and living in close quarters with only three other people, which can all impact team dynamics and cognitive performance."

Her fellow crew members were Kelly Haston, mission commander; Nathan Jones, a medical officer; and Ross Brockwell, a flight engineer. One thing they were able to simulate was walking on Mars.

"We had to traverse from the habitat through a series of hatches and into an airlock, don our simulated space suits, depressurize before opening the hatch to the Mars surface, and step into a large sandbox filled with Mars simulated regolith," Selariu said of the loose, dusty rock covering Mars' surface. "[That's] where we performed various activities while being guided by a … crew member from inside the habitat."

Selariu explained how the Navy prepared her for the year of isolation.

"Military experience in general prepares humans to be resilient, resourceful and disciplined," she said. "We often get to live in isolated, even hostile environments, and we understand how to cooperate and communicate with our team members, ... [operating] autonomously as a unit in difficult situations with scant resources and even no communication capabilities. Mars will demand all these as a basic skill set."

Despite having only three other people around the whole year, Selariu said they weren't short on entertainment in Mars Dune Alpha.

"We had plenty of digital books, prerecorded movies, TV shows, video games, board games and puzzles, but just talking to each other was, many times, entertainment in itself," she said.

Selariu said her year sequestered away from the world made her realize that Earth is truly "home."

"I missed most what I took for granted about Earth: how amazing it is that we can actually walk about and breathe its atmosphere - how cozy it is for so many life-forms to coexist. How amazing that it feeds us and keeps us safe and warm in a universe that is anything but friendly," she said.

On her last day in the Mars Dune Alpha, Selariu said she was excited to talk with friends and family in person, as well as partake in some other creature comforts.

"I look forward to green landscapes, freshly baked bread with butter, and a fully equipped gym," she said. "There are so many things I look forward to!"

Now that she's "returned" to Earth, Selariu said she'll move on to whatever mission the Navy gives her.

"I look forward to putting my boots back on and beginning the next journey," she said. "We can only guess where the future takes us."