Bears in Space!

Hibernation for astronauts. [Link]

Bradford's team is trying to leverage and extend medical advances in therapeutic hypothermia, which seeks to prevent tissue damage during periods of low blood flow by lowering core body temperature.

For every drop of 1 degree Fahrenheit in body temperature, metabolic rate decreases by 5 to 7 percent, Bradford said. The researchers are aiming for a 10-degree drop during manned Mars missions, or a 50 to 70 percent reduction in metabolic rate.

That's a big drop, but it's still a far cry from the suspended animation featured in sci-fi films such as the 1979 classic "Alien," which takes body processes all the way down to zero. [6 New Sci-Fi Movies to Watch in 2013]

"We're not freezing anybody. It's not cryopreservation; it's closer tohibernation," Bradford said. "So they're still breathing, and they still need sustenance." (Food and water would be delivered intravenously, he added.)

Ideally, the body-temperature drop would induce an unconscious state by itself, he added, so sedatives would not have to be administered to voyaging astronauts.

The team is investigating the best ways to cool an astronaut's core. The front-runner idea at the moment may be the gel pads that doctors use during hypothermia therapy, Bradford said. Injecting fluids into the bloodstream could also get the job done, but the researchers are hoping to avoid such invasive methods.

It's also possible to take another tack, Bradford said: Let the Mars-bound spacecraft cool down in the frigid depths of space, but work to warm the astronauts up to the desired temperature.

The longest anyone has remained in a medically induced hypothermic torpor to date is about 10 days, Bradford said. But that's likely not an upper limit, he stressed; rather, it's a reflection of the low medical need to keep people in such states for prolonged periods of time.

"We're trying to give [the medical community] a need, or a rationale" to push the 10-day record out to 30 days and beyond, and to look for any possible attendant complications, Bradford said.