Nasa explored putting astronauts into a hibernation-like state for Mars missions, but scientists are still trying to make the science-fiction idea safe for humans

• Image: AI GeneratedSending humans to Mars is one of Nasa's greatest ambitions, but the journey presents enormous challenges.
• A round trip could take well over a year, exposing astronauts to dangerous cosmic radiation, muscle and bone loss caused by microgravity, psychological stress and the need to carry vast amounts of food, water and supplies.
• To tackle these obstacles, scientists are investigating a concept that has long belonged to science fiction: placing astronauts into a hibernation-like state during the voyage.