Six scientists are close to wrapping up a year of near isolation in a Mars simulation on a Hawaii mountain.
The scientists are housed in a dome on Mauna Loa and can go outside only in spacesuits, the Hawaii Tribune-Herald reported.
They manage limited resources while conducting research and working to avoid personal conflicts.
Communication is delayed the 20 minutes, the length it would take to relay messages from Mars.
Kim Binsted, principal investigator for the Hawaii Space Exploration Analog and Simulation, said this simulation is the second-longest of its kind after a mission that lasted 520 days in Russia.