Packing For Mars (16 page)
Carter, too, was surprised to hear about the vibration study. He says the only promising data came from an animal study in which vibration appeared to speed fracture healing. “But in animals that just had low bone mass, it hardly changed the bone mass at all.”
Vibration has had an enduring quack appeal. Medical journals from 1905 to 1915 are rife with articles on “vibratory massage” and the many things it cures. Weakened hearts and floating kidneys. Hysterical cramp of the esophagus and catarrh of the inner ear. Deafness, cancer, bad eyesight. And lots and lots of prostate problems. A Dr. Courtney W. Shropshire, writing in 1912, was impressed to note that by means of “a special prostatic applicator, well lubricated, attached to the vibrator, introduced to the rectum” he was “able to empty the seminal vesicles of their secretions.” Indeedy. Shropshire’s patients returned every other day for treatment, no doubt also developing a relationship with the vibration machine.
Neither Tim nor Aaron is involved in an exercise study. “Me allowing myself to atrophy is going to be the hardest thing I’ve ever done in my life,” says Tim. Before he began the study, Tim was running three to five miles three times a week. He has a countermeasure plan of his own devising. “I heard a story of a POW in Vietnam.” He pauses for some Jell-O. The spoon clicks against the glass bowl. “He was locked in a cage.” Click-click-click. “Every day he played golf mentally. He improved his golf score by six strokes!” He leans back against his pillow. “So, mentally, I can go on a jog.”
Aaron has been pinching off pieces of dinner roll and listening without comment. He turns to face us. “I’ve been mentally doing squats.” He says he has considered suggesting to NASA that they enlist yoga masters or Buddhist monks to teach astronauts how to train their minds to fight the effects of zero gravity. I’m mentally enjoying the image.
The dinner cart returns, and the trays are taken away. The attendant places Tim’s glass on his table. “You didn’t finish your milk,” she says. Food intake is documented as part of the studies. Students hired to monitor the bed-resters make sure they don’t stuff food under their mattresses or behind the ceiling tiles. (Both have happened.)
“You have to eat everything,” says Aaron. “They will bring back your little tub of maple syrup and make you drink what’s left in it.”
PEGGY WHITSON HAS lived through the scenario that worries Dennis Carter and John Charles. In this scenario, astronauts who have been weightless in space for months or years, bone and muscle compromised, find themselves in an emergency situation: enduring the G forces of a crash landing, jumping out of capsule hatches, pulling colleagues to safety. For Whitson, as we learned earlier, it came to pass in 2008. She and two crewmates returning from the International Space Station endured a ballistic reentry and a 10 G landing. Sparks from the landing set the grass afire, and crewmate So-yeon Yi injured her back.
I talked to Whitson* about the incident. The day the interview was scheduled, there were technical problems with the phone system. By the time Whitson’s voice came on the line, six of my allotted fifteen minutes were up. I lurched from niceties straight into fire and snapping bones. “Commander, I am a huge admirer. Were you worried that your legs would break when you had to run away from the Soyuz capsule?”
“Nah,” said Whitson. She had more pressing concerns. Breathing during the 8 G’s of reentry, for instance, and not throwing up in front of Kazakh farmers in the field where they’d landed.
On her first ISS mission, Whitson said, she exercised so much that some of her bones were denser* than they were before she left. Her overall loss was less than 1 percent. “I did so many squats that I actually increased some in my hips.” Tom Lang, who has studied the skeletons of ISS astronauts, is not overly reassured by things like this. The returning astronaut’s total bone mass can be very similar to what it was before the mission, but that mass is distributed differently. Most of the regrowth takes place in the parts of the bone needed to support walking. But the parts of the hip that would break in a fall were nowhere near where they had been, leaving women like Whitson vulnerable to fractures in their retirement years.
When you fall, the top of your hip—or more specifically, the femoral neck and greater trochanter at the top of your thighbone—takes the brunt of the force in a side-smack manner. That’s not the same architecture that gets strengthened when you jog or do squats. The parts of the bone that are stressed by walking and everyday activity hold up surprisingly well with age. The body tends to redistribute bone to those areas—at the expense of other structures, including the ones you fall onto. For this reason, some osteoporosis experts feel that fall prevention is a better way to avoid broken hips than is load-bearing exercise.
I asked Tom Lang whether anyone had looked into the possibility of preventing hip fractures by simply thwacking the aged on the sides of their hips a few times a day. Not hard enough to break anything, obviously, but vigorously enough that the impact would stimulate the osteocytes to strengthen the structure. I didn’t expect him to say yes. He told me to contact Dennis Carter at Stanford University.
“It was just a concept,” said Carter when I called. “We never built it.” It didn’t thwack, it squeezed. “You’d sit in a lounge chair and have things at your sides squeezing your hips, right at the greater trochanter, where people fall and hit their hips.” It seems like a smart idea, but the companies Carter approached wouldn’t touch it. Because they thought the hips might break and the ladies would sue? “That, yes. And I think it was just too weird for them.”
Is it possible to bolster one’s hip bones by doing some type of controlled fall? Here too, I did not expect a yes. Carter told me that a graduate student at the Oregon State University Bone Research Laboratory had looked into this. As part of her thesis, Jane LaRiviere had subjects lie on one side, raise themselves up 4 inches, and then drop onto a wood floor. They did this thirty times in a row, three times a week. At the end of the trial, scans showed a statistically significant, though small, increase in bone density in the femoral neck on that side, as compared with the undropped-upon side. One of LaRiviere’s professors, Toby Hayes, felt that if the impacts had been a bit harder and the study lengthier, the results might well have been more impressive.
When you get right down to it, nothing works particularly well. Calcium’s a bust. To a certain extent, so is exercise. Bisphosphonates have come under scrutiny for giving some patients necrosis of the jawbone. “The state of the art for countermeasures right now,” John Charles allowed, “is the same as it was forty years ago.”
The astronauts don’t care. “They want to go to Mars,” says Charles. “That’s what they joined the program for.”
WHITSON IS CONFIDENT that someone will come up with a good, safe drug solution by the time a manned Mars mission becomes a reality. A more likely scenario is that genetic testing will by then play a part in astronaut selection. (There’s a large hereditary component to bone loss.) Charles envisions NASA recruiting Mars astronauts who are “almost bulletproof—people who never had a kidney stone in their lives, that come with high bone density, good cholesterol numbers, high radiation insensitivity…”
The bones of black women are 7 to 24 percent denser, on average, than those of white and Asian women. (I don’t have statistics for black men, but presumably they have sturdier bones as well.) I asked Charles whether NASA ought to consider an all-black crew for Mars. “Why not?” he said. “For decades, we had an all-blond, blue-eyed program.”
An all–black bear crew would be another way around the bone-loss conundrum. Black bears emerge from their dens after four to seven months in bed with bones as strong as when they turned in. There are researchers who believe that hibernating bears may hold the key to treating and preventing bone loss. I talked to one of them, Seth Donahue, an associate professor of biomedical engineering at Michigan Technological University. Donahue said that hibernating bears’ bones do break down, just like bed-resters’ and astronauts’ bones. What’s different is that their bodies take the calcium and other breakdown minerals out of the blood and reapply it to their bones. Otherwise the calcium level in their blood would build to a lethal concentration. Because during those four to seven months, the bears don’t get up to go to the bathroom. All the bone minerals that get dumped in the bloodstream as the bones dismantle themselves would stay there, accumulating. “So they’ve evolved a method to recycle that calcium.” And therefore not die. The bone protection is “a lucky consequence.”
Donahue and others have been studying the hormones that control bear metabolism to see whether they can identify some component that will help postmenopausal women (and astronauts) grow new bone. They’ve nominated bear parathyroid hormone. Donahue has a company that makes a synthesized version, injections of which are being tested in rats and eventually, if all goes well, will be tested in postmenopausal women. Even human parathyroid hormone makes women grow bone. It’s one of the most effective ways to increase postmenopausal bone density. Unfortunately, high doses make rats grow bone cancers, and thus the Food and Drug Administration limits prescriptions to one year and for women who’ve already had fractures. Donahue said bear parathyroid hormone doesn’t appear to have any adverse side effects, so keep your claws crossed that it pans out.
There’s another reason hibernating bears are interesting to NASA. If humans could be made to hibernate, to breathe one-fourth as much oxygen and eat and drink nothing for six months of a two-to-three-year Mars mission, imagine how much less food and oxygen and water one would need to launch. (The less baggage on board a spacecraft, the cheaper it is to launch. Once it reaches the speed needed to escape the pull of Earth’s gravity and leaves behind the air drag of Earth’s atmosphere, a spacecraft basically coasts to Mars.) Each extra pound of weight launched adds thousands of dollars to the project budget. Science-fiction writers glommed onto the idea decades ago, outfitting fictional spacecraft with high-tech, climate-controlled hibernaculums.
Do space agencies ever discuss human hibernation? They have, and they do. “It never dies,” says John Charles. “It just hibernates.” Charles puts little stock in the possibility. “Even if it did work, would we really short-supply a crewed vehicle on a three-year mission to Mars? What if the hibernaculum malfunctioned, and everyone woke up? How much food and oxygen do you carry, just in case? And when is that amount sufficiently large that the savings due to hibernation are lost?”
Here’s another reason it won’t work. Hibernating bears derive all their water and energy from reserves of fat that they build up by bingeing before they den. According to the Bear Center at Washington State University, a small (astronaut-sized) bear gorging on apples and berries consumes up to 40 percent of its body weight each day during this period. That’s about 65 pounds of food a day.
Six months of living on nothing but fat—even your own—probably isn’t healthy unless your body has somehow adapted to it. Little known fact: Hibernating bears have high “bad” cholesterol levels. (They also have very high “good” cholesterol—which probably explains why heart disease is unknown in bears.)
BED-RESTERS ARE not bears. They have to eat and drink and excrete, and that last one was Tim’s undoing. At FARU, B’s are to be M’d in bed, and no place else. Using a bedpan while lying flat on one’s back is an awkward and unnatural way to “make,” as my mother-in-law Jeanne likes to say. Tim sat up, and was caught on film by the camera aimed at his roommate Aaron’s bed. (He hadn’t drawn the curtain around that side of his bed because Aaron was out of the room.) “I didn’t think it would have that much of an impact,” he told me. “But it really threw off the scientific data.”* Tim was asked to leave.
Leon had no trouble with this particular aspect of bed rest. “After the first couple times, it’s second nature. And I go…a lot. I go at least four or five times more than any subject here. By the end of three months, I’ll be at around 260….” This is one way bed-resters are different from astronauts. With bed-resters, there are no taboo interview topics.
Including sex. Earlier, Joe Neigut was showing me the shower area, a tiled room the size of a horse stall, outfitted with a waterproof gurney. “So the shower,” I said, “is their only…private time, do you know what I mean?”
“Yes…” Joe replied. Then he began talking about the new shower head, which had replaced an industrial sprayer of the type used by restaurant dishwashers. I wasn’t sure he did know what I meant, so I asked Leon. Leon confirmed that the shower was “where most of them do it.” As with astronauts in orbit, masturbation is not formally addressed in the FARU rules or orientation. Leon, being Leon, asked the unit psychologist. “I mean, if it’s something that would throw off the test or something, I wouldn’t do it.” The psychologist blushed and then gave Leon the go-ahead, leaving the logistics up to him.
In a memoir, astronaut Michael Collins relates a story of a physician back in the Apollo era who recommended regular masturbation on long missions, lest astronauts develop prostate infections. The flight surgeon for Collins’s moon mission “decided to ignore that advice,” and ignoring seems to have been the basic approach to the human sex drive ever since. It’s the same way at the Russian space agency. Cosmonaut Alexandr Laveikin told me he too had heard that lengthy abstinence could cause prostate infections, but that the space agency pretends the issue doesn’t exist. “It’s up to yourself how you will deal with it. But everybody is doing it, everybody understands. It’s nothing. My friends ask me, ‘How are you making sex in space?’ I say, ‘By hand!’” As for the logistics: “There are possibilities. And sometimes it happens automatically while you sleep. It’s natural.” John Charles told me he’d heard about the link between prostate health and “self-stim”—at NASA, there’s an abbreviation for everything—but never heard any formal discussion, pro or con, of orbital masturbation.
Or two-party sex, for that matter. Here at FARU, that is covered in the rules, though indirectly. Visitors can’t sit or lie down on the beds. “My wife didn’t mind,” jokes Leon. “That was a plus of me leaving!” I had stopped in to his room again to say good-bye. He’s been showing me family photos on his computer.