If humans begin toin the next few decades, the one-way travel time of several months is going to make a long-haul international flight on Earth seem like a joyride.
Fortunately, one company is working to make it much easier to not just fall asleep on long interplanetary trips, but to hibernate through most of them.
Atlanta-based SpaceWorks has received two rounds of funding from NASA to investigate the feasibility of making a staple of science fiction a standard for actual space exploration. NASA, which this week , plans to spend its next few decades taking us to the Red Planet.
"Fourteen days is the point we have pretty high confidence that we can get to," said John Bradford, SpaceWorks president and former NASA engineer.
That's two weeks straight with the body's core temperature lowered by around 9 degrees Fahrenheit (5 degrees Celsius). The point of going hypothermic like that is to induce a sleep state called torpor that reduces the body's metabolic rate by as much as 50 percent to 70 percent, which means less consumption of oxygen and other resources. It's similar to what happens when bears hibernate.
"Our goal is to minimize the activity of the crew and reduce the amount of consumables and the support equipment they need on a mission [to Mars or somewhere else in the solar system]," Bradford said.
In other words, a hibernating crew needs far less room to move around, and less food to eat and even air to breathe. That means the spacecraft for a Mars mission could be smaller and lighter or hold more passengers per trip, making the whole interplanetary venture more efficient and less expensive.
After 14 days, Bradford says, the space travelers would warm up and wake, spend a couple of days recovering from the frigid fortnight and then get chilled again, repeating the cycle until reaching their destination.
Bradford agrees with Mars settlement enthusiasts like Elon Musk that this will be key to building a sustainable Martian city several thousand humans strong.
"We'll need ships that can send hundreds of people at a time, and we don't have any of the technologies propulsive-wise or things to really support that right now," he said. "But this technology, I think, enables that."
NASA did not respond to a request for comment about the potential to use a torpor chamber on Mars missions.
Chilling, with benefits
Putting wannabe Martians into hibernation comes with other benefits besides cramming more people into each flight to the Red Planet.
Bradford says research has shown that slowing the metabolism could help counter the muscle atrophy (bears don't lose muscle in the winter), bone demineralization and intercranial pressure that astronauts experience in microgravity. There's even some evidence it can help protect against radiation.
While the concept might remind you of scenes from the movies Interstellar and Passengers, it's based on a practice called therapeutic hypothermia used in hospitals today. Cooling the body to slow its metabolism can help newborns who've suffered traumatic births and can treat some heart attacks and certain injuries, including some battlefield casualties.
So far, though, it's unusual for someone to be put into a torpor state for more than one to three days. Isolated cases have been reported in Europe of patients staying chilled for a week with no adverse effects, and a 2009 report documented a patient at the Mayo Clinic in Jacksonville, Florida, who was in a torpor state for two weeks.
Bradford thinks it may be possible for humans to push the limit of hibernation even further.
"Ideally, maybe it's 30 days, if not the whole mission," he said. "I think in time you could get there."
For now, though, SpaceWorks is focusing on a process that could work in space for two weeks at a time.
There are other companies that work to freeze human bodies at the time of death (known as cryonics) in the hope that some future technology may be able to reverse whatever the terminal diagnosis was, but that's quite a different thing. So far as we can tell, SpaceWorks is the only company making an earnest effort at developing human hibernation for the purposes of space travel.
SpaceWorks has developed its concept, including a design for a "Torpor Inducing Transfer Habitat" that could be used on a mission to Mars, with funding from NASA's Innovative Advanced Concepts Program. NIAC has also supported other far-out concepts like a squid rover for exploring water worlds and robot bees to fly around Mars.
Now the team is beginning to transition from the conceptual phase to testing. One of the first tasks will be getting a new pharmaceutical approved for human trials that can lower the body's core temperature without relying on ice packs, gel pads, cold fluids or other external tools used today to induce therapeutic hypothermia.
The pharmaceutical "makes your body think it wants to be at 32 C (89.6 F) rather than 37 C (98.6 F)," Bradford explains.
From there, the focus will be on pursuing a better understanding of what happens to the body when it's in a hibernation state for longer than just a few days. There's more to learn about how the process could impact the brain, for example.
And there are other challenges that will probably need to be worked out, especially for long space journeys. The problem of pooping alone presents quite the quandary.
"The human body just doesn't really do well in space. We need to find some way to make the human body adaptable to the microgravity environment," said Dr. Doug Talk, SpaceWorks' medical team lead on the project.
"We have a term in medicine we use called 'biological plausibility;' meaning that if you look at what we're doing and look at the human body and how it works, it makes sense. This technology has biological plausibility; it could actually be beneficial to humans in space."
If it works, a trip to Mars could shrink from eight long months to just a few waking weeks in between 15 very long naps.
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