A team of six scientists have been welcomed back to Earth after a year-long mission on 'Mars'.
Funded by NASA, the Hawaii Space Exploration Analog and Simulation (HI-SEAS) exercise was as close to a trip to the red planet as we can currently get.
The scientists lived in close quarters in a dome on the slopes of Mauna Loa, on the Big Island.
There was no fresh air or fresh food and if they left the dome, they had to do so in a secure space suit, just like if they were on an inhospitable planet.
But now the team are finally back on planet Earth once more, feeling optimistic about future space travel.
"The University of Hawaii research going on up here is just super vital when it comes to picking crews, figuring out how people are going to actually work on different kinds of missions, and sort of the human factors element of space travel, colonisation, whatever it is you are actually looking at," says crew member Tristan Bassingthwaighte.
French crew member Cyprien Verseux thinks it shows a trip to the real Mars could be in the near future.
"I think the technological and psychological obstacles can be overcome."
HI-SEAS is the longest such experiment funded by NASA and the second-longest worldwide, after a Russian mission beginning in 2010 which lasted 520 days.