Four NASA astronauts are preparing to emerge from Earthbound isolation having spent more than a year on a simulated Mars mission.
Within the confines of a 158-square-metre, 3D-printed habitat at Johnson Space Centre in Houston, Texas, the crew members have, since October 2025, been living as though they were on the Red Planet.
This has included growing crops, managing limited resources, dealing with communication delays and conducting suited spacewalks on an imitation Martian surface.
At the same time, NASA scientists have been collating and processing health and performance data on the crew, which will feed into planning future long-term missions on Mars and mitigating spaceflight risks.
Members of the Crew Health and Performance Exploration Analog (CHAPEA) mission 2 - Ross Elder, Ellen Ellis, Matthew Montgomery and James Spicer - will leave their artificial home on Saturday, rounding off their 378‑day assignment.
They will have a chance to meet their families, with whom they have only been able to communicate via email over the course of their mission, with a "Mars-like communication" delay.
The crew will then undertake two weeks of post-mission evaluations and assessments.
These will help scientists learn what it takes for crews to adapt to the routines and demands of daily life on long-duration missions and give an insight into what future explorers might need to stay healthy, active and connected during deep space voyages.
The collected data could indicate how limited food and exercise systems will influence NASA's ability to carry out missions, including spacewalks on the surface of Mars.
It may also help in developing support systems for crew faced with communication delays lasting up to 45 minutes each way.
Michael Stenger, chief scientist for NASA's Human Research Program, said: "This mission has been incredibly valuable in starting to teach us how to understand requirements for year-long missions, including medical and psychological care, via communication delays.
"When combining this Mars-realistic mission analog with a suite of physiological, psychological, and performance measures in a rigorously controlled environment, we'll be able to translate the knowledge from these experiences to moon base and beyond."
The mission comes as NASA presses ahead with its ambitious plans for a permanent lunar outpost.
NASA is looking to land people back on the natural satellite in 2028, with a view to having a Moon base up and running by 2032, providing a continual human presence with routine crew rotations.
The pioneering project aims to develop the technologies needed for future deep space missions, including to Mars.