Kelly Drew was working in a lab in 1992 near the northern pole of a planet that was half a million miles per hour. She was distracted when Brian Barnes, a professor at the University of Alaska Fairbanks, came by her bench. He asked Drew to hold out her hands so that he could surprise her. She felt a lump in her hands. Drew assumed it was dead when he saw the brown animal with dagger-like claws curled up in a tight ball. Barnes exclaimed that it was in perfect health.

The most extreme squirrel on the planet can spend up to eight months a year in a torpid state.

Photograph: Mary Webb

For up to eight months of the year, the ground squirrel is just a resting place. The internal temperature of the animal is as cold as ice during that time. Its brain waves are so weak that they're almost impossible to detect. The squirrel isn't dead. It can return to 98.6 degrees in a few hours.

Drew couldn't detect the faintest signs of life as she cradled the unresponsive animal. She wondered what was happening in the animal's brain that allowed it to survive. She began to investigate a mystery that would take her decades into the future.

NASA, the Chinese National Space Administration, and SpaceX are competing to get the first person on Mars by the year 2040. A team needs to solve a series of design riddles in order to win. As an executive at SpaceWorks, an Atlanta-based engineering firm that tacklesambitious research projects for NASA, John has spent the past decade running the brutal math on one of them.

Engineers trying to get humans to the Red Planet are in for a rude awakening. In our daily quest to survive, we burn through a lot of food, water, and oxygen. It's difficult to design a light enough to reach a planet 140 million miles away. A crew of four will need at least 11 tons of food to complete an 1,100 day mission to Mars and back, based on the eating habits of the astronauts aboard the International Space Station. The meals would weigh more than the entire Perseverance rover. The weight of a fully fueled Mars-bound ship could easily exceed 330 tons as it leaves Earth's atmosphere, if you add in all the other life support essentials. It's almost impossible to imagine how a huge vessel could generate the power needed for a long journey.

The obvious solution to this problem is to slow the metabolism of crew members so they only need to consume a minimal amount of resources while in transit. In 2001, astronauts lie down in sarcophagus-like hibernation Pods, where their hearts beat just three times a minute. The question of how, exactly, can we safely power down a human body so it's just one step removed from death, then revive it on demand was the subject of a 21-year career at SpaceWorks by the man.

Early on in his research, he saw some promise in therapeutic hypothermia, a medical technique in which people who have experienced cardiac arrest are chilled until their internal temperature reaches as low as 89 degrees Fahrenheit. A damaged body that's struggling to heal amid reduced blood flow can benefit from this decrease in metabolism. Patients are usually kept in this hypothermic state for a day or two because the cold causes intense shivering and must be controlled with drugs. Some patients were kept hypothermic for more than a week. Why can't you do that for longer? How long can you stay in that comatose state?

It was feared that he would be branded a crank for suggesting that astronauts be put on ice. He persuaded NASA to fund a project looking at the feasibility of human torpor. If astronauts were kept cold for the bulk of their trip to Mars, the mass of their life-support resources could be cut in half. Torpor could help astronauts fight off a number of serious health risks, including radiation, extreme boredom and isolation. He says that you don't have real-time communications in the dark. A lot of people will say that they will just read a lot of books. I don't think that will last long.

There is reason to believe that we can modify our brains and bodies to mimic what hibernators do.

They soured on the technique as they dug into the details. The drugs used to control shivering stopped working as well. It would take weeks or months for astronauts to be intubated, meaning they would have to use tubes to breathe. The number of needles required to keep the IV fluids flowing was a problem that seemed likely to increase the chances of infections.

It was a dream for astronauts to be able to take a pill and then sleep on their own. It seemed strange, but parts of it were familiar to the person. There are scores of species that go torpid every winter, drifting into an unconscious state that reduces their body's craving for food and air. When they return to life in the spring, they don't show any signs of being sick from being away for long periods of time. It might be useful to understand how animals switch into low-power mode when their environment becomes harsher.

The small community of hibernation researchers, scientists devoted to studying the bears, bats, and lemurs for whom regular torpor is a fundamental aspect of existence was a good place to start. These researchers have been studying the changes that occur when certain species reduce their metabolism. There is good reason to believe that we can modify our brains and bodies to mimic what hibernators do.

For more than two decades, the University of Alaska's Kelly Drew has been researching the most extreme hibernator on the planet. The breakthrough she was referring to was a vital first step towards giving humans the power to turn themselves off and on at will.

Drew thought she'd never live in Alaska again after leaving college. She moved to Fairbanks in her teens to be near her father, who was a soil scientist at the university. Drew wanted a scientific career that wasn't tied to the wilderness. She moved to New York at the age of 22 to get her PhD in pharmacology and then to Sweden at the age of 30 to work on a project about brain metabolism.

Drew and her husband felt the pull of their home state after Drew's daughter was born. They were overwhelmed by the idea of being close to family. Even though she didn't have a job lined up, Drew decided to return to her hometown of Fairbanks. Drew remembers that they laughed and said that was the end of his career.

Kelly Drew studied the brains of the ground squirrel.

Photograph: Mary Webb

She concluded that the skeptics might have been correct. She thought she would be able to get a few grants to continue her work in Sweden, but no one was willing to give her money. She became more sure that her return had been a mistake after each rejection.

Drew was commissioned to study the brain chemistry of coho salmon by the National Science Foundation after a year of failed attempts. She used that gig to talk her way into borrowing a few square feet of lab space in the institute that she hoped would lead to bigger things.

In a surprising way, it did. During the salmon study, Brian Barnes hit a ground squirrel into Drew's hand. Drew was immediately curious about what was happening inside the ground squirrel's brain, a topic that hadn't been researched, and began to examine it using microdialysis, a technique in which tiny tubes are inserted beneath a living creature's skull. In the places where the tubes come in contact with the brain, the procedure can cause scarring. Drew was shocked when she couldn't detect any damage after performing microdialysis on the squirrel.

She says that you couldn't locate the probe. hibernation seemed to protect the brain from injury, so we began talking about it. Drew thought there could be great value in replicating that state in humans.

hibernation research flourished in the US during the Cold War. With the federal government fixated on besting the Soviet Union at every turn, there was lots of money to fund scientists who claimed their work could give the US a biological edge. Many of the researchers traveled through military facilities that are located in or near the northern part of the world.

Raymond J. Hock was a zoologist who wrote a thesis about bats. Air Force scientists were trying to make American soldiers immune to cold in the mid-1950's. In one ethically shaky experiment, the lab's personnel paid several Indigenous inhabitants of the South American country to wear temperature sensors and plastic hoods while they slept in freezing canvas tents. During his time in Fairbanks, he became interested in bears and lamented how little was known about their metabolism during their off season. He was able to assess how much their internal temperature declined during their annual torpor by going into the sleeping bears' dens.

The first sober and detailed look at how the American space program might benefit from the research he was helping to pioneer was published in 1960. He said that the main hurdle was the human heart's sensitivity to rapid temperature fluctuations. Several laboratories are working on ways to avoid it in man because the hibernators have learned how to do it.

He was able to assess how much their internal temperature declined during their annual torpor by going into sleeping bears' dens and measuring their internal temperature with sticks.

It has the potential to slow aging. He claimed that a hibernator will live longer than a non-hibernating mammal. aging should occur at half the normal rate if humans were able to keep an internal temperature about 13 degrees colder than normal.

In the early 1960s, while working at UCLA's White Mountain Research Center in California, Hock and his colleagues exposed marmots to sudden blasts of extreme cold. The heat generated by the brown fat in the animals' bodies was similar to the heat generated by humans. The key to enabling humans to survive frigid torpor was unlocked by the brown fat's innate power.

A tragic accident happened in 1970. Cold War research fell out of fashion as the war got older. The field was thought of as a backwater by biologists due to funding from the Pentagon and NASA decreasing. It takes a full year to gather data about an annual hibernation cycle and compare it to normal activity. Barnes introduced Drew to ground squirrels in 1992 and was the institute's director until 2001. You won't have the same amount of publications in a different field.

Drew, who is kind and tenacious, was so enamored with the ground squirrel that she went into hibernation studies. She camped out on the North Slope so she could catch as many squirrels as possible. The animals are used to living in deprivation and are willing to accept carrots as bait. She was able to get funding from the US Army's research office because she sold them on the idea of quickly cooling badly wounded soldiers on the battlefield. To make that happen, she had to identify the chemicals that triggered the hibernation in the ground squirrel and then test them to see if they work in humans.

Drew, who became an assistant professor at the Institute of Arctic Biology in 1993, initially believed that the main cause of squirrel activity was a neurotransmitter called GABA. The state in which a non-hibernating animal's metabolism is typically at its lowest is called the sleep state. Human's normal metabolism goes down by 15 percent while we sleep. The deep state of sleep known as hibernation is a state in which respiration is lowered, appetite is suppressed, and waste expulsion is controlled. The bears do not defecate or urinate during the winter.

Drew didn't bring about a long-term torpor when she dosed her animals with various chemicals. Drew celebrated her 40th birthday, mentord dozens of graduate and undergraduate students, and watched her daughter become a teenager while her attempts to find the key to hibernation remained mostly stuck in neutral.

In 2005, a dozen or so years into Drew's research on the squirrel, an undergrad chemistry major named Benjamin Warlick joined her lab as an assistant. He scoured databases to find new ideas about the chemicals that might make ground-squirrels sleepy. He found a paper from Fukuyama University entitled "Phase-Specific Central Regulatory Systems of Hibernation in Syrian Hamsters." The main text was written in Japanese but the brief abstract was written in English. The authors had snapped their hamsters out of torpor by blocking the A1 adenosine receptor in the animal's cells, according to the paragraph. Warlick flagged the paper for his boss because he thought it was worth a look.

It took Drew two years to have the document translated in full. When she read the English version, she came to the conclusion that blocking the A1 adenosine receptor could cause hamsters to stir.

When she dosed her ground squirrels with CHA, a drug well known for stimulating the A1 adenosinereceptor, the animals cooled down and began to hibernate. If the drug was given during the winter months, it would be a sign that something else was going on in the squirrel's brain that kept them on a yearly schedule. Drew was encouraged enough to work on a paper about the drug's mechanism of action in a squirrel.

She had to inject the drug directly into the animals' brains because she was so interested in CHA's effects. CHA slows the heart until it stops beating altogether, because it affects the A1 adenosinereceptor in the heart. It's not a good idea to stick needles into someone's brain outside of a hospital setting.

Drew had a poster made of all the data she hoped to include in the article. She hung it in the hallway to make sure she could see the numbers. She was struck not by how much she had accomplished, but by how little she knew. She hadn't figured out a way to turn her expertise into a safe and effective drug after placing a cold squirrel in her hands. The moment of triumph that should have been felt like a small defeat.

In the midst of her sadness, a thunderbolt hit: What if Drew could combine the CHA with another drug that would block its effect on the heart, but not the brain. An antagonist is a drug that blocks the ability of the human body to respond to it. Drew needed a molecule that was too large to cross the blood-brain barrier.

The agonist is everywhere if you think of it as a color map. Drew says that it stimulates all the receptors. You have to block those heart receptors because you don't want it to be stimulatory. Think of the villain as a blue color. It doesn't get into the brain when you put it in the body. The brain is still red even though the rest of the body is purple.

Drew had a lot of good candidates to choose from. The main ingredient in black tea is 8-(p-sulfophenyl)theophylline. This was combined with CHA to create a drug cocktail. Drew conducted a number of experiments on rats. She resuscitated the rats by stopping their hearts. The rats were either made hypothermic or left to heal with their metabolism at a normal rate after being pulled back from the verge of death. The rats that got the cocktail did better than the rats that didn't. Rats that were treated had their thermostats turned down by the drug. There was no reason for them to be given narcotics that might affect their breathing.

Drew's invention of methods and compositions for the treatment of ischemic injury to tissue using therapeutic hypothermia was granted a patent by the United States Patent and Trademark Office. The first illustration in the application is a picture of a squirrel with its head in the air, a nod to the small moment in 1992 that changed her life.

Drew was aware that her work would attract interest from the space- exploration industry, even though she was familiar with sci-fi movies like 2001 and Planet of the Apes. She wasn't surprised when someone from SpaceWorks contacted her. Drew was invited to become the company's chief hibernation consultant after the firm secured a second round of NASA funding.

Drew and Matthew Kumar were invited by SpaceWorks to test the CHA cocktail on pigs. The drugs slowly and safely lowered the animals' internal temperature to between 86 and 90 degrees Fahrenheit, which is not as cold as the state doctors can achieve. According to the summary of the experiment, the cocktail could lead to a torpor induction protocol that doesn't require any active cooling.

Around this time, other researchers shifted their focus to Mars. Sandy Martin, a University of Colorado Biologist who had spent her career building a tissue bank containing samples from various hibernating species, was approached by students organizing a one day symposium on space travel They asked her if her work could be used to help people on long voyages. Martin had never considered it seriously. It's always in the back of your mind as a researcher, but that wasn't the motivation for me. I wanted to say that this is a profound evolutionary adaptation. For a mammal to be so plastic in terms of body temperature and the ability of cells to survive is just so profound. Martin found a paper that advocated using IV cooling fluids to place astronauts on Mars. She forwarded the paper to her daughter, who was not a fan of SpaceWorks' proposal.

Martin thought that they needed to figure out how hibernators do it. They don't need to be intubated and they don't need feeding tubes. The thirteen-lined ground squirrel, a close relative of the Arctic ground squirrel, is the subject of a paper being worked on by her and her daughter. There is a crucial role that the TRPM8 plays in helping thirteen-lined ground squirrel thermoregulate.

NASA invited Drew, Martin, and a bunch of other people from the hibernation community to a two-day conference in Mountain View, California, in March of last year. The meeting was an opportunity for the biologists to make the argument that they could help humans achieve at least some level of true hibernation in the next 10 to 15 years, which was in line with NASA's plans to send humans to Mars in the late 19th century.

Martin said that the pervasiveness of hibernation among mammals suggests that humans can do it as well. The platypus is one of the three types of mammals that include us. Martin says that all three of the branches have some kind of animal in them. The most plausible explanation is that our ancestors were hibernators. Preparing our species to deal with the stresses of torpor may be a matter of altering genes.

The second phase of the human-torpor project was published four months after the NASA workshop. The document is candid about the many challenges that lie ahead and admits that little to nothing is known about how hibernation might affect an astronauts cognitive abilities. According to the report, NASA could begin testing Drew's drug cocktail on human subjects as early as 2036. The agency seems intent on making that happen, judging by the investments it has initiated.

The torpor is needed to make spaceships lighter. The agency has come around to the idea that it could help astronauts avoid some of the physical difficulties of long-haul space travel. The mission to Mars has a lot of unknowns, one of which is whether humans can survive the ravages of the Cosmic Ray. Even though the International Space Station stays within Earth's protective magnetosphere, there's no real way to dodge these cancer-causing particles, and scientists have yet to find a material that can shield against them. Human cells may become resistant to radiation if they are made less active. Scientists found that ground squirrels that were irradiated had a higher survival rate than their conscious peers.

You can give the cells more time to repair themselves.

Researchers interested in furthering the science of human torpor were given $4 million by the institute. The recipient is looking at the remains of an extinct human species that may have been found in the caves of northern Spain. An awardee is trying to establish the ideal temperature for people to sleep in. A professor of emergency medicine at the University of Pittsburgh is investigating the use of drugs on long-haul space flights.

Callaway's interest in human torpor came from his curiosity. He wants to use the technique to help people who show the early signs of a heart attack. Callaway looked for drugs that wouldn't knock vital organs out of commission and made therapeutic hypothermia a realistic option for such patients. He was able to get some encouraging results with a mild sedative used in anesthesia. He says that it worked well enough to convince them that it could be used in astronauts.

hibernation may be the only form of time travel that is remotely accessible.

The sedative effects of pure dexmedetomidine only last for 30 minutes, so it's not likely to be used on a spaceship. Callaway is trying to find a pill or patch that can be used to deliver a host of closely related drugs. He plans to expand his work next year to assess how well our species can recover from an extended period of low metabolism.

Callaway says that their master project is to have a group of people do a torpor for five days. I want them to sleep 20 hours a day, have a slightly lower body temperature, use less oxygen, and use less calories. We're going to do a lot of testing before they start and after they finish to find out what the problem is.

Callaway is aware of the innovations coming out of Kelly Drew's lab in Alaska, but he hasn't figured out how he will make his test subjects torpid. Drew was able to see the possibilities of taking inspiration from animal hibernators after visiting him in 2019. Callaway says that one lesson he's learned is that we would be naive to think that we're going to find a single drug that will let an animal or a person go into a deep sleep. One of the drugs in the class I'm studying right now, in combination with a drug that Dr. Drew is studying, could be the answer in 10 years. It will be that cocktail of drugs that will give astronauts a safe sleep.

Callaway doesn't believe that the astronauts will ever be as cold as the ground squirrel. Bears reduce their internal temperature by a few degrees during the winter, so they are pretty effective hibernators as well. He says we can duplicate that in this decade.

Drew has been trying to figure out how a 312 pound mammal shuts down for the winter for nearly 50 years. She believes she was lucky to have been able to solve the problems quickly. She told me that people in the industry wouldn't tolerate this.

Kelly Drew is in her lab. There is a photograph of Mary.

Drew has an animal in her lab. There is a photograph of Mary.

Thanks to researchers like Drew, the private sector is starting to notice its potential. Sandy Martin, a professor at the University of Colorado, arranged for her bank of hibernator tissues to be licensed to a former student. A Silicon Valley startup co-founded by Grabek seeks to improve treatments for heart and lung diseases by discovering why hibernators can survive shocks to internal organs that would kill most humans.

It's similar to having a heart attack when these animals awaken from torpor. In order to develop pharmaceuticals that can help cardiac patients, FaunaBio wants to identify the compounds that hibernators use to prevent or repair cell damage.

Even those of us in good shape may find it tempting if it becomes a realistic option. At least a couple of transhumanist dreams can be realized with the help of Induced Torpor. It's like life extension if you're not solely bent on extending your life. The fountain of youth seems to be offered by hibernation. Earlier this year, a team at UCLA found that yellow-bellied marmots, which hibernate for as much as two-thirds of every year, possess more robust genetic material than was anticipated. The researchers wrote in Nature that hibernate may prevent aging.

hibernation may be the only form of time travel that is remotely accessible. The ancient Egyptian practice of mummification was imagined to be such a technology in a story written in the 19th century. The awakened Egyptian says that his civilization's historians lived their lives in installments. The method for preventing our history from degenerating into absolute fable is to hibernate for a few hundred years. No one wants to create a cocktail that can induce torpor for hundreds of years. A biological fast- forward button that would allow someone to skip months or more into the future could appeal to a certain type of adventurer.

I like the idea of being able to take a short break from the constant din of my thoughts. I am wondering what it would be like to take a break for a week or two. One of the main characters in the 2001 novelization was depicted as longing for the psychological liberation of torpor. They were not responsible or bored.

The vulnerability of the hibernator is a recurring theme. In 2001, three astronauts are killed by a ship's operating system after spending time in a film. The shock and social dislocation that long-term hibernators experience when they emerge into worlds that have gone haywire in their absence is one of the main themes of many other works of sci-fi. If we go under for a short time in order to reach Mars, it will be difficult to reenter consciousness. Within hours of warming up, the cold-blooded ground squirrel returns to his old self. If they had human self-awareness, that wouldn't be the case.

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