Four volunteers returned after spending 378 days in a 160-square-foot facility at NASA’s Johnson Space Center in Houston, where they took part in a simulated mission to Mars. Ross Elder, Matthew Montgomery, James Spicer and Ellen Ellis had entered the facility on October 19, 2025, and communicated with the outside world with delays of up to 22 minutes. They cared for plants, exercised, maintained the living space and equipment, and simulated Mars spacewalks using virtual-reality headsets.

The participants were not astronauts. The experiment examined the effects of long-term isolation in a confined space, crop cultivation, and the impact of equipment failures and repair demands. The facility was built with 3D-printed lava concrete as a model for possible future space settlements. NASA plans another, longer isolation experiment next year, while the volunteers said they hoped their participation would support future missions to the Moon and Mars.