Nothing works as it’s supposed to in zero gravity, or zero G, as it’s also known. “Even something as simple as a fuse,” astronaut Chris Hadfield told me, mistaking me for someone who knows how a fuse works. Now I know: Fuses have a metal strip that melts in response to a surplus of current. The molten bit drips away, leaving a gap that interrupts the power flow. Without gravity, the droplet doesn’t drip, so the power continues to flow until the metal boils, by which time the equipment has fried. Zero gravity is part of the reason NASA price tags seem so extravagant. For every new piece of equipment that goes up on a mission—every pump, fan, throttle, widget—a prototype must be flown on the C-9 to be sure it works in weightlessness.
Overheating equipment is a common theme in zero G. Anything that generates heat tends to overheat, because there are no convection currents in the air. Normally, hot air rises—because it’s thinner and lighter; the livelier molecules are all bouncing off each other and spreading out more than they do in cooler air. When hot air rises, cooler air flows in to fill the vacuum left behind. Without gravity, nothing is any lighter than anything else. It’s all weightless. The heated air just sits where it is, getting hotter and hotter and eventually causing damage to the equipment.
Human machinery tends to overheat for the same reason. Without fans, all the heat that exercising astronauts generate would hang around their body in a tropical miasma. As would exhaled breath. Crew members who hang their sleeping sacks in poorly ventilated spots get carbon dioxide headaches.
In the case of the Space Weld Team, it is the human machinery that’s most notably out of commission. It’s not something you can fix with a fan.
The Astronaut’s Secret Misery
On the ceiling of the C-9 is a red numerical display of the type you see at deli counters, telling patrons which number is being served. This one is counting parabolas, twenty-seven so far. Three more and it’s over. We were told not to “go Supermanning around the cabin,” but I have to break the rules. As gravity fades out on the twenty-eighth parabola, I pull up my legs, crouch on the windowpane, and then gently uncoil, launching myself across the cabin of the plane. It’s like pushing off from the wall of a swimming pool, but the pool is empty and it’s air you’re gliding through. It’s probably the coolest moment of my entire life. But not of Pat Zerkel’s life. The Missouri space welder has been belted down in the front row of seats. Though weightless, he appears heavily burdened. A white bag hovers near his face. It is held open with both hands, like a hat carried through a crowd for tips.
“OOOooulllrr-aaghchkkk, khkkk.” Pat has been ill since the fourth parabola. At parabola number 7, the flight surgeon came over to hold him steady during the weightlessness, hoping it would help. (And to keep him, as he told me later, from “floating away helpless and vomiting everywhere.”) At parabola number 12, men in blue flight suits gave Pat a shot and helped him to the back of the plane, where he would remain for the rest of the flight.
The special evil of motion sickness, the genius of its cruelty, is that, generally speaking, it hits you when you’re up. A sunset sail on the San Francisco Bay, a child’s first roller-coaster ride, a rookie astronaut’s first trip to space.* There is no faster route from joy to misery, from yee-ha to oooulllrr-aaghchkkk.
In space, motion sickness is more than an unpleasant embarrassment. An incapacitated crew member makes for the most costly sick day in the world. An entire Soviet mission, Soyuz 10, was aborted due to motion sickness. You’d think science would have it licked by now. It’s not for want of trying.
TO FIGURE OUT how best to prevent motion sickness, you first need to figure out how best to bring it on. Aerospace research has excelled at the latter, if not the former, and perhaps nowhere more triumphantly than at the U.S. Naval Aerospace Medical Institute in Pensacola, Florida: the birthplace of the human disorientation device. In a 1962 NASA-funded study, twenty cadets agreed to be harnessed to a chair mounted on its side on a horizontal pole. Thus affixed, the men were rotated, rotisserie style, at up to thirty revolutions per minute. As a reference point, a chicken on a motorized spit typically turns at five revolutions per minute. Only eight of the twenty made it to the end of the experiment.
The motion sickness inducer of choice these days is the rotating chair.* Here the rider sits upright upon the seat, as if preparing to take dictation. A small motor causes the chair to spin on its base, conferring, at first glance, a joyful air to the proceedings, as though the subject had set herself awhirl—the tipsy stenographer at the office Christmas party. At the experimenter’s command, the subjects, eyes closed, tilt their heads left and then right while spinning. I took a brief turn in the rotating chair that resides in the lab of space motion sickness researcher Pat Cowings, at NASA Ames. At the first head tilt, something lurched inside. “I can make a rock sick,” said Cowings, and I believe her.
What has aeromedical science learned from the combined tortures of motion sickness research? For starters, we now know what causes it: sensory conflict. Your eyes and your vestibular system can’t get their stories straight. Say you are a passenger belowdecks on a heaving ship. Since you are moving along with the walls and floor, your eyes report to your brain that you are sitting still in the room. But your inner ear tells a conflicting story. As the ship moves you up and down and around, your otoliths—tiny calcium pebbles that rest atop hairs that line the vestibule of the inner ear—register these movements. If the ship dips down into a trough, for instance, the otoliths rise; when the ship crests, they press down. Because the room is moving with you, your eyes detect neither. The brain gets confused and, for reasons not well understood, responds by nauseating you. Soon you are heaving too. (This is why it helps to stay up on deck, where your eyes can register the boat’s motion relative to the horizon.)
Zero gravity presents a uniquely perplexing sensory conflict. On Earth, when you’re upright, gravity brings your otoliths to rest on the hair cells along the bottom of the inner ear. When you lie down on your side, they come to rest on the hairs on that side. During weightlessness, the otoliths, in both situations, just float around in the middle. Now if you suddenly turn your head, they are free to ricochet back and forth off the walls. “So your inner ear says you just laid down and stood up and laid down and stood up,” says Cowings. Until your brain learns to reinterpret the signals, the contradiction can be sick-making.
Given the culpability of the human otolith, it is not surprising to learn that sudden head movements are extremely, to use the lingo of motion sickness experts, “provocative.” If you look at back issues of Aerospace Medicine, you can find pictures of grim-looking World War II troops with their heads wedged between padded vertical slats on the walls of troop transport planes: someone’s attempt to stem the vomitous tide. (The smell of other people’s emissions in close quarters is also highly “provocative.” Cowings likes the term “inspirational.”) Airsickness and seasickness were serious enough problems during the war that the government, in 1944, convened an entire United States Subcommittee on Motion Sickness. (Then again, it has also convened a U.S. Subcommittee on Poultry Nutrition and one on sedimentation.) Charles Oman, resident motion sickness expert at the National Space Biomedical Research Institute, confirmed the perils of wanton head-swiveling by mounting accelerometers on the backs of astronauts’ headwear. The ones who, just by nature, tend to jerk their heads around a lot are the ones most likely to suffer from motion sickness during a mission. What’s true in space is true in a car on a winding road: No matter how much the driver behind looks like the GEICO caveman, don’t whip your head around to look. According to work done by prolific 1960s motion sickness researcher Ashton Graybiel, even one head movement in highly susceptible people produces a measurable increase in their sweat level—an indication that nausea is just around the bend.*
“We actually proposed making a beeping beanie,” Oman said. If astronauts moved their head too fast or too much, they’d hear a beep letting them know. Oman did not record the astronauts’ responses to the beeping beanie proposal, but I’m guessing they were fairly, as they say, “provocative,” for no astronautical beanie-wearing ensued. Oman did manage to get astronauts on one mission to agree to try out padded collars designed to discourage extraneous head movements, which they promptly removed. “It was perceived as an irritant,” Oman said ruefully.
Astronauts have to deal with the mother of all sensory conflicts: the visual reorientation illusion. This is where up, without warning, becomes down. “You were working on a task…and apparently reorienting your ‘down’ without thinking about it, and then turning away and finding that the whole room was completely cattywampus to what you thought it was,” recalls a Spacelab astronaut quoted in one of Oman’s papers. (This may have been Pat Zerkel’s problem; he told me he’d had “the distinct feeling of losing any sense of up or down.”) It happens most readily in spaces with no obvious visual clues as to which is the floor and which the ceiling or wall. The Spacelab tunnel was notorious. One astronaut found traveling through it so reliably nauseating that, he told Oman, he’d sometimes pay a visit simply to make himself “get better by vomiting.” Even just a glimpse of a fellow astronaut oriented differently from oneself could bring it on. “Several Spacelab crew described sudden vomiting episodes after seeing a nearby crew member floating upside down.”* Nothing personal.
Experts like Oman keep changing their minds about whether drugs are a good idea. In space, as at sea, recovery is a process of adaptation; if you’re under the covers in the fetal position, you’re not exposing your vestibular system to the new reality. Overdoing it, on the other hand, can mean crossing the threshold and making yourself sick. Drugs help keep astronauts out of bed, moving and going about their work. But they also confer a false sense of immunity, encouraging one to overdo it. Motion sickness drugs don’t make you immune; they simply raise the threshold for sickness.
For anyone taking a short trip, across the Channel or on the C-9, drugs are the answer. NASA gave us Scop-Dex (the dextroamphetamine counteracting the sedating effects of the scopolamine). Even then, most flights have at least one or two “kills,” as the blue flight suits call the stricken. Pat looked queasy before the parabolas even began. It’s possible he’s someone who developed a conditioned response to the sight of a vehicle—in his case, a plane—that once upon a time made him horrifically ill. People who say they “get sick just looking at a boat” are not always exaggerating. (Relaxation and counterconditioning techniques can help in these cases.) People also develop conditioned responses to the smell of vomit. “This is why motion sickness can seem contagious,” says Oman.
One thing the Pensacola research proved is that it helps to focus on something other than how you are feeling. The eight who finished rotisserating on the human disorientation device were those who had been given “constant mental arithmetic” tasks or timed button-pushing sequences to complete. Mental as opposed to written, because the last thing you want to be doing when you’re fighting off motion sickness is reading. In particular, avoid reading papers such as “Analysis of Vomitus and Contents of Gastrointestinal Tract.”
RUSTY SCHWEICKART DID everything wrong. Schweickart was an astronaut on Apollo 9, charged with testing the life-support backpack that the Apollo 11 crew would wear on their history-making stroll on the moon. Schweickart was to put it on, power it up, and head into the depressurized Lunar Module. Because he’d been sick during parabolic-training flights, he’d been exceedingly cautious the three days leading up to the spacewalk. “My whole modus operandi…” he said in his NASA oral history, “was to keep my head as still as possible and not to move around a lot.” There’s the first problem: He delayed his adaptation. On day three, Schweickart had to put on his EVA suit. This is, as he describes it, a “real contortionist challenge” with a lot of ducking down and doubling over. Problem 2: head movements. “Suddenly I had to barf,…and I mean, that’s not a good feeling. But of course you feel better after you barf.” Encouraged, he continued his preparations, moving over to the Lunar Module. Problem 3: the dreaded visual reorientation illusion. “You’re used to being up, and when you go over there, it’s down.” When he got there, he had to wait for his crewmate to catch up to where he was on the checklist of tasks. “I’ve basically got nothing to do.” Problem 4. “When your mind is suddenly—[its] priorities are gone, then…malaise gets the top priority in your brain. All of a sudden, I had to barf again.”
With space motion sickness, the impulse to vomit can hit with unusual suddenness. One of Oman’s Spacelab interviewees recalls sitting with a colleague who was eating an apple. “Right in the middle of it, he said, ‘Aw gee!’ threw the apple in the air, and vomited just like that.” Launch-pad workers stuff extra vomit bags in rookies’ pockets before liftoff, but even then, unfettered hurls are common.* NASA etiquette is to clean it up yourself. As one of Oman’s Spacelab interviewees says, “Nobody else is going to do that work for you—and you sure don’t want anybody to.” Though you couldn’t accuse Schweickart’s fellow astronauts of a lack of compassion. Herewith, the most touching moment in the 1,200-page mission transcript from Apollo 9.
COMMAND MODULE PILOT DAVE SCOTT: Why don’t you let all the rest of the powering down stuff and all that be ours, and you go get your suit off, clean up, try to eat, and go to bed?
SCHWEICKART: Okay. Cleaning up sounds pretty good.
SCOTT: Get one of those towels and wash and…all that stuff. That’ll make you feel better.
SCHWEICKART: Okay. You want to watch the radio?
SCOTT: Yes, I’ll take it.
For reasons we’ll explore momentarily, NASA goes to great lengths to keep its men and women from throwing up in their helmets during a spacewalk. Schweickart and Scott had a serious talk about whether they should skip this particular EVA and just tell NASA they’d done it. Apollo 9 was a critical step in the race to put a man on the moon. The EVA life support system that Neil Armstrong and Buzz Aldrin would wear on the moon had to be tested, as well as rendezvous and docking equipment and procedures. “This is already March of 1969,” recalls Schweickart in his oral history. “The end of the decade is coming right up…. Is this basically a wasted mission because Schweickart’s barfing?…I mean, I had a real possibility in my mind at the time of being the cause of missing Kennedy’s challenge of going to the moon and back by the end of the decade.”
What happens if you vomit in your helmet during a spacewalk? “You die,” said Schweickart. “You can’t get that sticky stuff away from your mouth…. It just floats right there and you have no way of getting it away from your nose or your mouth so that you can breathe, and you are going to die.”
Or not. U.S. space helmets, including those of the Apollo era, have air channels directing flow down over the face at 6 cubic feet per minute, so the vomit would be blown down away from the face and into the body of the suit. Disgusting, yes. Fatal, no. I ran the whole death-by-vomit scenario past Tom Chase, a senior spacesuit engineer at Hamilton Sundstrand. “There would be an extremely remote potential for any barf to get into the oxygen return duct, behind the astronaut’s back,” he began. “It’s one of five returns, including four at the extremities, so even if one was blocked, it would be unlikely to create a complete system blockage. If it somehow did, then the crew member could shut down their fan and go on ‘purge,’ where they would vent out the Display and Controls Module purge valve and continue to get fresh oxygen flowing into their helmet from their pressurized tanks.” Chase shut down his fan for a moment. “So you see we’ve really thought this one through.”