Video report by ITV News Correspondent Lucy Watson
Six people who had confined themselves to a dome on a remote Hawaiian volcano to simulate a mission to Mars have emerged after eight months in isolation.
The team, which included a British man, tucked into a fresh fruit buffet after having eaten mainly freeze-dried food since the start of the year.
Samuel Payler, a doctoral candidate at the UK Centre for Astrobiology at the University of Edinburgh, and five other researchers entered the HI-SEAS (Hawaii Space Exploration Analog and Simulation) habitat on Mauna Loa in January.
They were testing how humans would respond to living in isolation for extended periods of time.
The experiment - run by the University of Hawaii - intended to help Nasa determine the requirements for sending astronauts on long missions, including trips to Mars.
We need to send humans out because it's important for the future of the species. I think it's actually really important to get off Earth. If you look back at the geological record, it is just full of mass extinctions.
The 1,200 sq ft site included small sleeping quarters for the crew members, a kitchen, laboratory, bathroom and simulated airlock area.
The crew's daily routine involved preparing food, exercising, scientific research and tracking the use of resources such as food, power and water.
Communication with support crew on the outside world was allowed but a 20-minute delay was imposed on messages to imitate what the reception would be like between Earth and the red planet.
The international team of four men and two women included engineers, a computer scientist, and space researchers.