Powering Up for Mars

Astronaut Mike Hopkins gives us an inside look at NASA’s
fitness program as the space agency prepares for a
manned flight to the Red Planet.

October 2016

By Allan Richter

Michael Hopkins baled hay on his family’s Missouri hog farm, played on three sports teams through middle and high school, and immersed himself in four-hour daily workouts for the University of Illinois football program. When he left college, he began running long distances and completed several marathons. His resolve to stay fit served him well when he joined the National Aeronautics and Space Administration (NASA) as an astronaut and endured the increasingly taxing rigors of space travel.

Like Hopkins’ progressively demanding fitness regimen, NASA has been pushing the boundaries of its ambitious space program by taking its astronauts from the roughly one- or two-week missions of the Apollo and space shuttle programs to months-long operations and, most recently, a nearly one-year mission aboard the International Space Station (ISS). In addition to helping NASA understand the impact of long-duration space flight on astronauts, experiments aboard ISS are giving scientists insights into medical, technical and communications systems needed for missions into deep space, particularly Mars. Manned missions to the Red Planet are slated for the 2030s.

Between September 2013 and March 2014, Hopkins spent 166 days aboard the ISS, except for two spacewalks, completing 2,656 orbits of the Earth and traveling more than 70 million miles. Hopkins’ lengthy mission, among others, helped pave the way for that of astronaut Scott Kelly, a veteran Navy pilot, who returned to Earth this March after a record 340 days aboard the ISS. Researchers are trying to better understand how the immune system works in deep space by studying data from medical experiments on Kelly against research on his identical twin brother, astronaut Mark Kelly, who was earthbound during Scott’s flight.

Space is tough on the human body. Absent the routine pressure that an environment with gravity has on the skeletal system, bone density tends to degrade in space—by up to 2.5% a month. Muscles atrophy. And astronauts suffer impaired vision during and after their space flights.

“I lost bone mass, my muscles atrophied and my blood redistributed itself in my body, which strained my heart,” Scott Kelly said in a news release announcing his forthcoming memoir, Endurance: My Year in Space and Our Journey to Mars, which publisher Knopf said it will release in November 2017. “Every day, I was exposed to ten times the radiation of a person on Earth, which will increase my risk of a fatal cancer for the rest of my life. Not to mention the psychological stress, which is harder to quantify and perhaps as damaging.”

Which is why a robust fitness regimen and careful scrutiny of the health of astronauts spending long periods in space are critical to Mars missions. “The microgravity environment can be hard on the body,” Hopkins, 47, a lean, broad-shouldered US Air Force colonel, says in an interview at Johnson Space Center in Houston. Even for someone as fit as Hopkins.

Staying Fit in Microgravity

Some of the key countermeasures, as NASA calls them, to the grueling effects of long-term space flight take place in a room at Johnson roughly the size of the average American two-car garage. It houses practice replicas of the three pieces of exercise equipment aboard the ISS, save for some variations to account for the differences in gravity: a treadmill, a stationary bicycle and an apparatus for weightlifting called an Advanced Resistive Exercise Device, or ARED.

At 1,000 pounds and the size of a compact car, the ARED is the largest of the three. It is also the most versatile. “You can do squats, you can do a bench press, deadlifts, all of those major lifts that are not only important for your muscles, but they’re also loading up your bones,” Hopkins says as he adjusts the ARED for a demonstration. “What happens then is your muscles and your bones say, ‘Oh well, I can’t just atrophy, I can’t just lose my density, I’ve got to stay strong.’”

In fact, the ARED has given NASA one of its biggest victories against bone density loss. When astronauts were exercising with ARED’s smaller predecessor, the Intermediate Resistive Exercise Device, or IRED, their recovery upon landing back on Earth took weeks, sometimes months. After NASA migrated to ARED in 2009—the same time Hopkins left his post as a special assistant to the vice chairman of the Joint Chiefs of Staff to begin astronaut training—astronauts began seeing a more immediate recovery upon landing.

Astronaut Tracy Caldwell Dyson flew on the Space Shuttle Endeavor on a two-week mission in 2007. On a mission to the space station in 2010, when she completed 176 days in space, she became one of the first astronauts to use ARED aboard the ISS.

“After coming back from my shuttle flight I remember feeling extremely heavy, and the effect of one G on my body after almost 13 days in space was notable,” she recounts. “Then on my station flight coming back I assumed I would feel that way in order of magnitude because of the number of days I spent up there. I felt heavy in the first hour or so when I landed but then when I got back to Houston I was walking on my own and, other than being fatigued naturally, I felt pretty good. I recovered in less than 10 days. I was driving in less than 10 days and I was doing push-ups and pull-ups.”

Because conventional weights would have little effect in the microgravity environment of the ISS, ARED employs pistons inside canisters; the system works like a syringe to create pressure when the pistons are pulled back, explains Bob Tweedy, who, as a Countermeasures System Instructor, shows astronauts how to use and repair the equipment. In doing a squat, for instance, an astronaut has to stand and force the pistons against the force of the vacuum: The machine is converting the pressure into a load. Adjusting a fulcrum changes the amount of load.

ARED can create up to 600 pounds of load versus IRED’s 300 pounds. “When we were using IRED we noticed that a fairly strong crew member could max out the system very early in their mission,” Tweedy says. Because ARED’s higher loads are more challenging to the skeletal system, “bone density numbers are getting better,” he says. “Some crew members have not lost any bone. There are still losses with some other people, but the big picture is that the rate of loss and the total amount of loss is a lot less. We’re trending in the right direction.”

Also helping to strengthen the bones of astronauts, Hopkins says, is the ISS treadmill. “You might think of the treadmill as a cardio [machine], and it is for that, but it’s also for the impact,” Hopkins says. “As you’re running and you’re hitting down and stepping down, that is also sending loads through your bones. That’s telling them to continue to stay strong.”

Step on a treadmill on the ISS the way you would on Earth, however, and you’ll float away. Before demonstrating a run on the practice treadmill at Johnson, Hopkins dons a harness that keeps him tethered to the treadmill via bungees made of surgical tubing and a protective cover. The bungees are clipped to the harness at the waist.

“There are sensors in the treadmill that will show you what your load is, like stepping onto a bathroom scale,” Tweedy explains, “and if you want more load, you simply remove the necessary amount of clips, which would put more stretch on the bungee, which would, in turn, load you even more down to the deck.”

Each astronaut’s harness is fitted before he or she heads to space. And, while astronauts can adjust the speed and loads of the equipment manually, each person’s specific protocols for each piece of equipment are programmed by fitness trainers known as Astronaut Strength and Conditioning and Rehab Specialists, or ASERs, who remotely track the health of the astronauts while they are in space.

“You may run four minutes at that high intensity and then they’ll drop you down for a minute of slower pace and then take you back up,” Hopkins says. “Or, like I used to on Sundays, I’d just go for a long run so I might not go as fast and I might not load up as much. I might drop it down a little bit but I would run for an hour.”

The harness made Hopkins’ treadmill workouts aboard the ISS the most uncomfortable of the three exercise machines. “When I was doing 185 pounds, 200 pounds, you’re carrying it all in your shoulders and in your hips,” Hopkins says, “and that gets uncomfortable after a little bit.”

Just minutes after hooking himself to the practice treadmill at Johnson, Hopkins says he can already feel the load in his shoulders. “I’ve only been on it five minutes, not even five minutes, I’m not really loaded up, and I can already feel it,” the astronaut says. “So what I would do when I was running, just like when I’m backpacking, I constantly adjust. I’d move those to the outside a little bit,” he says, motioning to harness straps. “Shift the load more to my hips. Do that for five minutes, come back, and tighten it up. It was just constant, constant movement for me.”

While the treadmill offered the least comfort of the three machines, Hopkins says, the stationary bicycle was the most intense because of the steep hills programmed into the workout.

Unlike the practice exercise bike at Johnson Space Center, the bike aboard ISS did not have a seat or handlebars. “You don’t need any of that equipment when you can float,” Tweedy says.

The major distinction between exercise equipment aboard the ISS and the machines in your local gym is the addition of what NASA calls a Vibration Insulation System on the equipment in space. A heavy workout on Earth poses no risk in setting your health club out of kilter, but it does aboard the space station. So NASA engineers built into the equipment shock absorbers of sorts that can mute or sop up the energy astronauts produce during exercise so it doesn’t shift to the ISS.

Aboard the space station, Hopkins used the ARED daily and alternated between the treadmill and stationary bike every other day. The focus, after all, was on resistance training, especially as it became increasingly clear to NASA that the higher-load resistance workouts were easing the recovery of astronauts back home.

Specialized Trainers

Mark Guilliams is one of three ASERs at Johnson Space Center who work with the astronauts. In addition to tracking astronaut health during space missions, ASERs train astronauts before their flights and work to ease their recovery after landing.

In sports parlance, the job is similar to trainers who work with athletes before, during and after a game, except Guilliams’ job and that of the other ASERs is not as linear. At the time of our August interview, for instance, Guilliams was working with two astronauts pre-flight, one inflight and one post-flight. And the co-operation between Russia and the US aboard the ISS extends to the fitness trainers as well; in addition to the four astronauts, Guilliams was working with several Russian cosmonauts.

It was to the Russians that the NASA fitness trainers first turned for guidance, Guilliams recalls, when the space agency was readying its own astronauts for lengthy space flights in Shuttle-Mir, a cooperative program in the mid-90s between NASA’s space shuttle operations and Russia’s Mir space station. Operating in low orbit from 1986 to 2001, Shuttle-Mir began before the first ISS module was launched in 1998.

After adapting some of the Russian practices, however, the NASA fitness trainers realized that the Russian methods were “fairly conservative,” Guilliams recounts. “We realized that we could be much more aggressive in how we train. We were always kind of delicate and worried about it.”

For example, Guilliams took issue with the Russians’ heavy reliance on a swimming pool to aid in post-flight recovery. By the time of the third ISS mission, NASA’s trainers departed from the Russian practice and stopped using a swimming pool as a main component of post-flight recovery.

“I didn’t feel putting them back into a weightless environment was the best way to get them to recover,” Guilliams says of the astronauts. “If you’re trying to recover to a one-G environment, to me the best way to do that is to force them into the one-G environment.”

Today, Guilliams steers his charges toward NASA’s swimming pool only for relaxation after a vigorous workout. For post-flight recovery, Guilliams, who worked with Hopkins for his 166 days in space, says he puts the astronauts through a series of stretches and movements that work as much of the body simultaneously as possible. You won’t see them sitting on the floor doing stretches, but standing and moving backwards and forwards.

“That way I’m forcing you to stretch the muscles,” he says, leaving his seat to demonstrate. “It’s the same movement, but now I’ve put your head into it and you have to balance. You have to work coordination. You have to work all your stabilization muscles, and I’m working neurovestibular [the system that affects balance and helps people orient their bodies] at the same time. That’s a very simple movement. We do things like moving on one leg at a time, so we progress through that to make it more difficult for them.”

For Guilliams, the faster astronaut recoveries since the installation of ARED aboard the ISS are testimony that the focus on resistance over aerobic training is the right approach—and that Hopkins and other crew members are rightly spending most of their NASA gym time at the weight-lifting area toward the rear of the facility.

The NASA gym, housed conveniently across from a building that serves as the quarters of astronauts in post-flight recovery, looks as if it could be in any American strip mall. A basketball hoop is near the front of the facility, and most of the workout equipment, set atop a handsome rich-blue floor, is familiar.

Except one—an apparatus called an Anti-Gravity Treadmill from AlterG, a Fremont, California, rehabilitation equipment supplier. The device encloses a treadmill and an astronaut’s lower body in an airtight rubberized chamber, and pressure pushing the astronaut upward relieves impact on the runner’s bones. Guilliams recommends the machine, as well as a treadmill built into the floor of a pool in a nearby aquatics area, as a transition to a more rigorous post-flight recovery regimen.

Eating for Long Missions

Astronauts don’t stay in shape by exercise alone. Culinary practices in space have come a long way since Mercury and Gemini astronauts sucked down baby food from tubes and popped dried cubes of food coated in starch to prevent crumbs. Astronauts on the ISS can choose from eight categories of foods and beverages containing some 200 items, says Vickie Kloeris, who manages the ISS food system from Johnson Space Center. Astronauts also can access nine additional containers of foods they choose themselves—even some canned goods off grocery shelves, as long as they meet NASA’s standards for shelf life and microbiological safety. Those standards tend to be comparable to those of commercial food producers.

Nutritional requirements aboard the space station also tend to reflect those of Earth, with two notable exceptions: iron, which astronauts need less of because fewer red blood cells are produced in space (a process fueled by iron); and vitamin D, which they need more of because they do not receive direct sunlight (taken in supplement form).

Long-duration space flight, particularly the three years needed for a roundtrip to Mars, has Kloeris’ food lab concerned about the rates at which vitamins degrade in food supplies. As her lab’s advanced food technology team explores how to extend the shelf life of food, it remains concerned about vitamin C, in particular, which “tends to degrade fairly rapidly,” she said. “But we have discovered in certain things like powdered beverages it’s very stable.”

Existing propulsion systems can get a crew to Mars in six months, and astronauts will have to remain on the Red Planet for about 18 months before they can return because they have to wait for Earth and Mars to align closely enough to make the return trip feasible. Taking all that into account, and because NASA plans to send food supplies to Mars ahead of the astronauts, Kloeris calculates that the food the crew will eat on their six-month trip home will be between five and seven years old.

“It will depend on how they power the cargo vehicle that they use to pre-position the supplies,” Kloeris says. “If they use a chemical engine to get it there the food on the return trip will probably be about five years old. They are talking about the possibility of using a solar-powered cargo vessel, and if they do that it will be a slow boat and take much longer to get to Mars. Then the food they eat on that return trip will be about seven years old.”

It’s a powerful reason why NASA is working to expand its Veggie fresh-produce gardening program. The Veggie unit includes a growth chamber and what NASA terms “plant pillows,” containing seeds that are bathed in red, blue and green LEDs. In May 2014, a crew aboard the ISS first germinated the Veggie seeds, grew them for a month and sent them to Earth for safety testing. When they were deemed safe, Scott Kelly and his crewmates on their later ISS mission used Veggie again, to grow red lettuce that they ate.

More than a few NASA officials, however, say the psychological benefits of gardening with Veggie outweigh the nutritional ones. “Growing food. Sharing food. Having meals with your friends. There’s something about gathering around food and harvesting fresh food” that lifts the spirit, said Ray Wheeler, lead scientist for Advanced Life Support at the Kennedy Space Center, in an interview at the Orlando space center. In a basement at Kennedy, plants were bathed in the purplish glow of red and blue LED lights in mockups of Veggie.

Vision Loss

Space poses another vexing health challenge: the vision impairment that many astronauts endure during and after long-duration flights. Among suspected causes is the shifting of fluids from the lower body to the head, as well as particulate matter such as dead skin and dust that float in microgravity and irritate the eyes.

But for the past five years, Scott Smith and the Nutritional Biochemistry Lab he leads at Johnson Space Center have been following clues that point the way to a genetic disposition, as well as levels of B vitamins, for the vision issues. In a building in which anything that came back from the moon in the Apollo missions used to be quarantined, but which now houses Smith’s lab, poster-size charts and graphics about the genetic link line the walls, like photos of suspects in a detectives’ squad room.

The breakthrough that pointed Smith and his team toward exploring the genetic link was so powerful that Smith remembers the day and hour—February 18, 2011, at 3:30 p.m.—that his deputy, Sara Zwart, entered his office and announced, “There’s something going on with one-carbon metabolism.” Zwart was referring to a pathway by which chemical interactions within the body’s cells convert nutrients from foods into molecules that help the body function. The one-carbon metabolism pathway moves single carbon atoms from one compound to another, and involves folate, and vitamins B6 and B12, among others. Smith’s team found higher levels of homocysteine, linked to heart attacks and strokes, in the blood of astronauts whose vision was impaired. The finding led to the study of genetic differences in one-carbon enzymes. It was NASA’s first foray into the genetic testing of its astronauts.

One week before the interview with Smith, his department received approval to expand its study. As Smith notes, the team needs to find more details to learn how to treat the vision issues, which also include elevated intracranial pressure from thicker retinal nerves.
Though all the crew members who have developed vision issues have been men, Smith’s team found another segment of the population with similar problems: women with polycystic ovary syndrome. Last month, Smith’s team began working with the Mayo Clinic to collect blood from women with the affliction.

The study of these women supports one of the ISS program’s guiding missions: to conduct research “off the Earth, for the Earth.” About half of the ISS program’s research findings are aimed at expanding NASA’s push deeper into space, while half are designed to produce medical and other advances on Earth.

“If we can understand this thing,” Smith says, “by figuring out how to treat it in astronauts we might significantly advance the medical treatment of 10% of the population, which is women with polycystic ovary syndrome.”

Cramped Quarters

NASA is making other strides as it learns more about what it will take to safely bring a crew to and from the Red Planet. Because a vehicle carrying a crew to Mars will have to be much smaller than the football field-size International Space Station, its contents must similarly adapt. Kloeris says her food team has developed a nutrient-dense breakfast bar, for example, far healthier than the many sugar-loaded bars posing as health food found in grocery stores.

NASA’s fitness experts, meanwhile, are busy studying various prototypes of exercise equipment that will offer astronauts the loads of ARED but in a more compact footprint. At the same time, trainer Guilliams says, the Russians appear to have conceded that the American preference for resistance training is the right approach and are developing a weight-training apparatus of their own.

As for fitness, NASA has already proven that in the ISS it is capable of creating the ultimate wellness retreat in space.

“We do a VO2 max test where we’re on a bike, we put a tube in our mouth and they’re recording how efficiently we’re using our oxygen, and I came back better than when I went up,” Hopkins says. “While you’re onboard Station you have a very controlled diet, the food is nutritious, it’s maybe a little high in sodium, but in terms of fat content it’s very lean food. And you’ve got someone on the ground who’s tracking what you’re eating, how many calories and what types of calories you’re putting in. And for two hours a day I was guaranteed time on my calendar to work out. I mean, who of us down on Earth except for professional athletes gets that? For my conditioning I probably came back in the best shape I’ve ever been in.”

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