The new sci-fi film “Passengers” is filled with action, romance and—like many a good space yarn—hibernation or sleep pods. A malfunction in the devices results in a 90-years too early wake-up call for the film’s protagonists and re-awakens in the audience the notion of decades-long deep-space missions truncated through peaceful bliss. The sleep system director Morten Tyldum presents in the movie is necessarily the stuff of movie magic, but researchers working with NASA to study the possibility of hibernation on manned missions to Mars say the approach has some scientific underpinnings.
“Somebody did some homework,” says Dr. John Bradford, president and COO of SpaceWorks Enterprises, Inc., an Atlanta-based aerospace engineering firm specializing in advanced concepts and technologies. “They get into a little more detail than recent movies. So, I definitely enjoyed that. There was hibernation or suspended animation in “Interstellar”, for instance, and that was like five seconds onscreen and then it was done. There was no real showing of a recovery period or how the system could work.”
Bradford’s team at SpaceWorks, with funds acquired through the NASA Innovative Advanced Concepts (NIAC) program, is researching whether modern medical procedures can be advanced toward a viable form of crew hibernation. In a paper presented in September at the 67th International Astronautical Congress, the team argues that “medical progress is quickly advancing our ability to induce torpor, a deep sleep hibernation-like state, in humans for extended periods of time.”
The team is currently exploring whether this state can be achieved through Therapeutic Hypothermia (TH), a medical treatment used in hospitals for cases of traumatic injury or cardiac arrest that lowers a patient’s core body temperature around 10 degrees (89-93°F). Bradford says that NASA could use an advanced form of this procedure to reduce both the physical and psychological toll of deep space travel on its crews and also to ameliorate some engineering problems associated with maintaining a manned mission. “Mars is a six-month trip. With current technology that six months takes a lot of food and energy, consumables—like water and oxygen—and mass for habitats. So I started thinking about, what are these challenges and how can we minimize them.”
Current research on TH, as presented in his team’s paper, has focused on animals and human subjects suffering from serious injuries. The report shows that hibernation can be induced in non-hibernating animal species and that unhealthy human subjects have recovered from as many as 14 days of TH treatment. “All the outcomes when they do apply it (TH) are positive,” Bradford says, “so we don’t have any reason to think there would be detrimental impacts, at least on the short term if you just took a person and cooled them and left them there for four or five days in that condition and brought them back. We wouldn’t expect any negative physiological or neurological outcomes. But it hasn’t been done, and it hasn’t been done because there’s really no medical rationale to do it. So we’re kinda creating that rationale with ‘Hey, we could do this for space.’”And to do this for space, Bradford’s team is addressing both medical and engineering challenges. On the medical side, SpaceWorks wants to develop a non-invasive technique to achieve the TH state. Several of the contemporary medical methods are invasive. One method, for example, involves a cooling catheter inserted into a patient’s vascular structure while another requires tubes placed in nasal cavities. “We’d like to avoid anything that’s too invasive or requires more work or effort on the part of the crew than just taking a drip of something and laying back,” he says. Invasive methods also increase the risk of infection, according to Bradford, and so his team has turned its attention to naturally occurring drugs like Adenosine, prescribed today to fight a range of conditions from irregular heartbeats to kidney failure, in hopes of finding the foundation for a non-invasive system.
Bradford points to animal research where scientists used Adenosine to lower the core temperature of non-hibernating species. In humans, he says, the drug could reduce an individual’s shivering response, allowing engineers to induce a TH state through ambient cooling. “We’re not talking about extreme temperatures. We’re trying to get the core temperature down 10 degrees.”
But cooling in space can take many forms and could involve systems with everything from sun shields to layering, cryogens or even heat exchangers used to add heat. Over the next two years, SpaceWorks engineers will be exploring several options. Bradford hopes to show NASA that using hibernation on the crew will provide benefits to overall vessel design in addition to reducing the need for consumables. The need for radiation shielding, for instance, would be reduced if the crew were confined to smaller habitats.
SpaceWorks’ hibernation system is not currently part of NASA’s official program plan for its manned missions to Mars, but Bradford says he is “optimistic and a little bullish” about the potential for his idea. “I think we could address a lot of problems,” he says. “I’m optimistic that if we can get a decision to push on this capability further that it can be done in the timeframe to support the first missions.”