NASA and the European Space Agency explore ways for astronauts to hibernate during long space journeys

To mitigate the logistical, physical, and psychological problems with long trips through space, such as a trip to Mars, research is being done to investigate whether humans could be put into some sort of hibernation for part of the trek. The idea is to induce a state in humans similar to torpor, the state that hibernating animals, such as bears and squirrels, enter.

This could be achieved through therapeutic hypothermia, currently used to treat patients in cardiac arrest or suffering from traumatic brain injuries. Cooling the body down by a few degrees reduces the body's demand for energy and oxygen.

"SpaceWorks Enterprises, an aerospace engineering based in Atlanta, Georgia, believes that therapeutic hypothermia could also be a good way of placing space travellers into a "synthetic torpor". The firm has received funding from Nasa to flesh out its idea, which would see astronauts placed in compact pods where they would enter a two-week stint of extended hibernation, before being active for a couple of days, and then going back into stasis again. This could be done on rotation, so that there would always be a member of the crew awake, addressing safety concerns or any emergencies that might occur."

Research is being done on exactly how the body and brain would enter a state of torpor.

"[S]tudies suggest that a part of the brainstem called the raphe pallidus, which helps control automatic bodily processes, may be involved. Matteo Cerri at the University of Bologna, Italy, and his colleagues found that they could get rats and pigs – which do not normally hibernate – to enter a torpor-like state by inhibiting this region.

"[Leopold Summerer, head of the European Space Agency's (Esa) Advanced Concepts Team] believes the mitochondria – a structure found in every living cell that converts chemicals in food into energy the body can use – may also play a role. His team is currently conducting experiments on the cells of hibernating Syrian hamsters to see if they have special adaptations that could help them cope with stressful environments."