Our bodies aren't meant for space. We require too much maintenance to speed through the stars. We need a steady supply of things absent from space -- namely water, food and oxygen. We crave warmth but won't find it in deep space, where the average temperature is -270°C. Even if we could survive in an icy vacuum without sustenance, we'd probably go insane without distractions and room to move.
But aeronautic engineers believe they have found the key to solving that puzzle: put your space travellers to sleep. Long-term cryogenic sleep may be the key to getting humans to Mars and beyond. But it may first come to a spa near you.
This post originally appeared on Van Winkle's
An old idea for a new age
Alien's Weyland-Yutani Corporation had the right idea about how to cut spaceflight costs -- your overhead plummets when your crew is in hibernation. Indeed, dozens of sci-fi flicks have employed cryogenic sleep as a way to send their stars into the stars. But while it seems like the most speculative sort of science fiction, these imagined spaceship stasis chambers may become working reality in the next three decades.
According to a NASA-funded study, keeping astronauts unconscious almost halves the haul of any given trip. When a crew is placed in an inactive state, many of the ship's subsystems can be removed and the space and equipment needed for humans significantly cut down. The negative psychological and social aspects of prolonged space travel could be mitigated, too.
Currently, 14 days is the longest a human being has been recorded surviving in stasis. To just get to the Red Planet -- our closest celestial neighbour aside from the Moon -- astronauts would need to be under for 10 times as long. With our present rocket technology, it takes six to nine months to travel the 55 million kilometres between Earth and Mars.
Drawing from emerging technology and centuries-old medical techniques, engineers are looking to keep people unconscious for weeks at a time. But while studies have been encouraging, hypernative and cryogenic sleep keep getting interrupted. Initially promising research has hit dead ends, and funding for continuing research has been elusive despite media and popular interest in unconscious astronauts.
Hibernation for humans
One company, called SpaceWorks, thinks it's cracked the problem. Since 2013, the Atlanta-based aerospace engineering firm has been exploring the possibility of keeping space travellers in a hibernation-like state. That year, the company received one of 12 NASA Innovative Advanced Concepts (NIAC) grants to pursue Phase 1 of its "Torpor Inducing Transfer Habitat For Human Stasis To Mars" project.
SpaceWorks believes a common medical procedure is the key to sending people into the furthest reaches of space. "The nearest equivalent to hibernation currently experienced by humans is a medical condition called therapeutic hypothermia," said SpaceWorks researcher Doug Talk.
Therapeutic hypothermia, used to treat cardiac arrest and babies born with certain birth defects, reduces body temperature by about five degrees through methods ranging from ice packs and cooling blankets to catheters. SpaceWorks believes they can use therapeutic hypothermia to put human beings into torpor, the long hibernative state that bears enter to endure long winters. Once in torpor, the subjects could be transported through space.
Cold is at the heart of stasis. Cold slows the functioning of internal organs, dialling down the speed of the heart and metabolic systems. You'd need less sustenance and take up less space than a conscious person. And since you're unconscious, there's no risk of cabin fever.
The SpaceWorks team has acknowledged that their plan sounds like science fiction. A February 2014 presentation included images of movie characters in stasis, from Alien to a carbonite-encased Han Solo. Indeed, the illustrations for the torpor habitat bear a sharp resemblance to their movie predecessors, with unconscious people standing in glass tubes with padded backs.
Each body is tended to like fragile meat-based hardware. A centrally positioned one-armed robot moves over the unconscious travellers, making sure the basic needs of their bodies are met. In addition to pumping in water and nutrients and delivering sedatives to keep the bodies from shivering, the robot periodically administers mild electric shocks to ward off muscle atrophy.
Using cold to slow metabolism is actually an old, Earthbound technique dating back to the Greeks, when the father of modern medicine, Hippocrates, packed snow and ice into soldier's wounds. Today, the same basic principle is in common medical practice to an extent that the ancient physician couldn't have imagined was possible.
Since 2003, therapeutic hypothermia has been common treatment in critical care of newborn infants suffering from foetal hypoxia and for adults with head trauma, neurological injuries, stroke or cardiac arrest. Doctors lower a patient's temperature to keep them alive long enough for them to access lifesaving techniques and materials, like donor organs, distant medicine or antidotes.
In most medical cases, doctors put patients in therapeutic hypothermia for minutes or hours. SpaceWorks want to use it for days at a time.
Despite being unconscious for multiple days, astronauts probably wouldn't wake up refreshed. Talk said that during hibernation, a person would likely cycle through episodes of wakefulness (minus awareness) and non-REM sleep.
"They'd probably wake up in a mental state similar to sleep deprivation and need a short period of sleep recovery to transition from sleeping passenger to active explorer," he said.
But SpaceWorks' president John Bradford argues that the experience of being in torpor wouldn't be unpleasant. The hibernation experience, he said, would be like going under anaesthetic for surgery.
"It would probably be very similar to going in for a medical procedure in the hospital where they put you to sleep," Bradford said. "There would be some mild sedatives and a lot of that is to suppress the shivering your body would do naturally."
For better or worse, unlike bears, humans can't live off stored fat during periods of torpor hibernation. While in stasis, the body would subsist on intravenous feeding tubes pumping in the bare minimum amount of lipids, amino acid and dextrose needed to keep a person alive.
Compared to the habitats and supplies necessary to take a waking crew to Mars, it's a thrifty way of approaching space travel. Thrifty and a little unappetizing in some details, namely the proposed water recovery system, which would filter water from cabin humidity and crewmember urine to use as drinking water.
Bradford said they envision having astronauts in stasis for two weeks at a time. They would wake up in staggered patterns, making sure that one crew member would be conscious at all times. The waking crew member would spend a day or two awake ensuring that the equipment keeping his unconscious colleagues alive was working and be able to check on mission updates from Earth.
At the end of their waking shift, they would help the next crewmember due for consciousness to wake up.
NASA's cold feet
For a time, poison was poised to answer to the question of long-term stasis. Biochemist Mark Roth used hydrogen sulphide, a toxic material deployed in World War II chemical warfare, to temporarily knock out mice. His work gained national media attention and he presented his findings in a 2010 TED conference.
Unfortunately, he was reportedly unable to reproduce his initial success on larger mammals. Roth, who didn't reply to an interview request, is reportedly looking into other methods of suspended animation.
Arizona surgeon Peter Rhee, who helped save Rep. Gabrielle Gifford's life after her near-fatal headshot, has FDA approval for human trials of an emergency medical suspended animation technique that would allow doctors to stop a patient's heart for 60 to 90 seconds, allowing a doctor to perform emergency surgery while the blood pumping organ is still.
While the research is promising for medical uses, it's not of much direct help to Bradford and his team. Roth's research is ongoing after the tease of a breakthrough with the mice. And Rhee's proposed technique involves swapping out a patient's blood for cooled saline for a very limited amount of time -- not a practical solution for long-term hibernation.
The least invasive cooling process SpaceWorks has found is the RhinoChill System, which sprays coolant into the brain through the nose and gradually lowers body temperature by one degree per hour. After about six hours, the body temperature drops to 89 to 93 degrees, at which point they would reach a torpor state for the long trip to Mars.
SpaceWorks completed Phase 1 of their research last year, presenting NASA with a final report last summer. While their work attracted national media attention, NASA declined to fund Phase II with a NIAC grant, which would have entailed a $US500,000 investment.
A NASA spokesperson said that competition for NIAC studies is intense, but otherwise declined to say exactly why NASA passed, citing privacy concerns. Bradford said he wasn't sure exactly why NASA made their decision.
"Maybe they weren't convinced at the mission level of the benefits and wanted us to move on the next actual testing, like animal testing and human testing, start getting into the actual physiological experiments," he said. "That's how we read the feedback. The program that we had bid too, the funding was outside their scope. The funding was not enough to start moving into actual medical testing."
Bradford said that NASA has other funding outlets besides the NIAC grants that SpaceWorks can attain, and that SpaceWorks is looking at ways that they can cater their torpor to NASA's needs.
"NASA is looking at utilization of their test facility, so we can envision experiments there," Bradford said. "Utilization of the international space station, you know, putting animals up and having a control group that was in a therapeutic hypothermic state for periods of time and quantifying the impacts. There are a number of programs that would support that sort of research so that's where we're working now."
Additionally, Bradford said they have reached out to private space exploration-related firms like Elon Musk's Space Exploration Technologies Corporation, or Space X, to see if they might have any use for their ideas or technology.
Meanwhile, Bradford is busy promoting the project, updating the public on progress through his Space torpor blog and giving interviews. He's also presented SpaceWork's plans in settings like science fiction conventions, where the prospect of hibernation-enabled space travel has been met with enthusiasm (and offers to volunteer).
"We have a roadmap of how to advance the technology," he said. "And there are additional commercial applications. It's always good if you can get private investments outside of dependency of government money and funding cycles."
One potential commercial application under consideration is using torpor in an earthbound setting as a kind of intensive two-day recuperative therapy. While going unconscious in extreme cold may not sound like anybody's idea of a spa weekend, it has been proven to help bodies heal in medical settings.
"Maybe it's something you go into on the weekend for 48-hour torpor sleep," Bradford said. "The reason they do it for traumatic injuries is that it lowers the metabolism and blood pressure and such and gives the body time to respond and heal from these injuries, so maybe there is some therapeutic benefit."
Top image via SpaceWorks