Packing for Mars: The Curious Science of Life in the Void

7. THE CADAVER IN THE SPACE CAPSULE NASA Visits the Crash Test Lab

Crash simulation is a world comprised largely of metal and men. The simulator at Ohio’s Transportation Research Center resides in a clanging, hangar-sized room with few places to sit, and none of them upholstered. The room holds little beyond the crash sled, on a track down the middle, and a few engineers in safety goggles, forever walking back and forth with coffee mugs. Other than the reds and oranges of warning lights and hazard signs, color is hard to find.

The cadaver seems almost a homey touch. Subject F wears blue Fruit of the Loom underpants and no shirt, as though he were lounging around in his own apartment. He looks deeply relaxed. As dead men do. Are. He slumps slightly in his chair and his hands rest on his thighs. Were F alive, he would not be so relaxed. In a few hours, a piston as fat as a redwood will shoot a slug of pressurized air at the seat in which he’ll be strapped. Both the force of the impact and the position of the seat can be adjusted to create whatever crash scenario a researcher requires: a head-on into a wall at 65 miles per hour, say, or one car broadsiding another going 40. Today it’s NASA’s new Orion capsule, dropping from space onto the sea. F gets to play astronaut.

In a space capsule, every landing is something of a crash landing. Unlike a plane or the Space Shuttle, a capsule has no wings or landing gear. It doesn’t fly back from space; it falls. The Orion space capsule has thrusters that can correct its course or slow it down enough to drop it from orbit, but not the kind that can be fired to soften a landing. As a capsule reenters the Earth’s atmosphere, its broad bottom plows into the thickening air; the drag slows it down to the point where a series of parachutes can open without tearing. The capsule drifts down to the sea, and if all goes well, the touchdown will feel like a mild fender-bender—2 to 3 G’s, 7 at most.

Touching down on water rather than earth makes for a gentler landing. The trade-off is that oceans are unpredictable. What if a cresting wave slams into the capsule as it’s coming down? Now the occupants need restraints that protect them not only against the forces of being dropped straight down, but also against a sideways or upside-down landing impact.

To be sure Orion’s occupants are unhurt no matter what wild card the seas present, crash test dummies and, lately, cadavers have been taking rides in an Orion seat mock-up here at the Transportation Research Center. The landing simulations are a collaboration involving the Center, NASA, and Ohio State University’s Injury Biomechanics Research Laboratory.

F sits on a tall metal chair beside the piston track. Graduate student Yun-Seok Kang stands at his back, using an Allen wrench to mount a wristwatch-sized block of instrumentation on an exposed vertebra. Along with strain gauges glued to various bones on the front of the body, these instruments will measure the forces of the impact. Scans later this evening and an autopsy will reveal any injuries caused by that force. Kang was up late with yesterday’s cadaver and in early this morning, but he’s alert and cheerful. He has one of those happy, high-achieving personalities that self-help programs promise but rarely manage to create. He wears rectangular glasses and long bangs that march around to the sides of his head. His gloved fingers are glossy with fat. The fat—because it’s slippery and because there’s a fair amount of it—makes Kang’s task difficult. He has been working on this mount for more than half an hour. The dead are infinitely patient.

F will be taking a hit on his lateral axis. Picture a foosball figurine—the little wooden soccer player with the skewer run sideways through his rib cage. That skewer is the body’s lateral axis. Say the foosball man goes for a drive, and another car T-bones his car at an intersection. His body and organs, if he had any, would be accelerated to the left or right along that skewer. In a head-on crash or a rear-ender, they’d be accelerated along the transverse axis: from front to back, or vice versa. The third axis that researchers consider is the longitudinal—along the spine. Here the foosball player is operating a helicopter. It stalls and drops straight down to the ground. Foosball man’s heart stretches down on its aorta like a bungee jumper. Should have stuck to sports.

Because astronauts are reclining on their backs during touchdown, a space capsule hitting the ocean in calm conditions creates a force on the transverse axis—front to back—by far the body’s most durable. (Lying on their backs, fully supported and restrained, they can tolerate three to four times as much G force—a tenth of a second of up to 45 G’s—as they could seated or standing, wherein the more vulnerable longitudinal axis takes the strain.)[31]

Crashes often involve forces along not just one axis, but two or three of them. (Though simulations study just one at a time.) Add high seas to the capsule touchdown equation, and now you have to consider forces along multiple axes. A useful model for the kind of impact NASA must plan for—multiaxis and unpredictable—is the race-car crash. The week I visited Ohio, NASCAR’s Carl Edwards, traveling at close to 200 miles per hour, slammed another car, launching his own high into the air, where it spun like a flipped quarter before slamming down into the wall. Whereupon Edwards casually got out and jogged away from the wreckage. How is this possible? To quote a recent Stapp Car Crash Journal paper, “a very supportive and tight-fitting cockpit seating package.” Note the word choice: package. Safeguarding a human for a multiaxis crash is not all that different from packing a vase for shipping. Since you don’t know which side the UPS guy’s going to drop it on, you need to stabilize it all around. Race-car drivers are strapped tightly into custom-fitted seats with a lap belt, two shoulder belts and a crotch strap to keep them from sliding down under the lap belt. A HANS (Head and Neck Support) device keeps the head from snapping forward, and vertical bolsters along the sides of the seat keep the head and spine from whipping left or right.

Dustin Gohmert, a NASA crew survivability expert, has spent a lot of time talking to the people who design restraint systems for race cars. He and two colleagues have traveled from the Johnson Space Center to oversee the simulations this week. Gohmert has agreed to answer some questions while Kang and three other students finish instrumenting F. Gohmert has blue eyes and black hair and a lively Texas wit that he mostly sets aside while speaking into a tape recorder. He sits straight-backed and motionless while answering my questions, as though merely talking about upper torso restraints is holding him still in his chair.

Early on, NASA had dismissed race-car seats as models for Orion. For one thing, race-car drivers are sitting up, not reclining. Bad idea for astronauts who’ve been in space for a while. Lying down is not only safer (provided you don’t have to steer); it keeps astronauts from fainting. Veins in the leg muscles normally constrict when we stand, to help keep blood from pooling in our feet. After weeks without gravity, this feature stops bothering to work. Compounding the problem is the fact that the body’s blood volume sensors are in the upper half of the body. Where, without gravity, more of the body’s blood tends to pool; the sensors misinterpret this as a surplus of blood, and word goes out to cut back on production. Astronauts in space make do with 10 to 15 percent less blood than they have on Earth. The combination of low blood volume and lazy veins makes astronauts lightheaded when they return to gravity after a long stay in space. It’s called orthostatic hypotension, and it can be embarrassing. Astronauts have been known to faint during postmission press conferences.

There is a problem with lying on your back in a spacesuit in a very safe seat: “We threw a racing seat on its back, put a guy in it, and said, ‘Can you get out?’” recalls Gohmert. “It was like putting a turtle on its back.” Some months back, I watched a horizontal egress (getting out of the capsule) test of a suit prototype at Johnson Space Center. The verb “to turtle,” as in “I’m kind of turtling out,” was in fact used.

Getting out fast is mainly a concern when something goes wrong: The capsule is sinking, say, or it’s on fire. The last time things went wrong aboard a space capsule, it was the Soyuz capsule, returning to Earth with members of the ISS Expedition 16 and 17 crews, in September 2008. (NASA has been paying the Russian Federal Space Agency to fly ISS crews home when no space shuttle is available.) The Soyuz module entered the atmosphere out of position—as it had with Boris Volynov aboard in 1969. This interfered with the aerodynamic lift that normally helps flatten its course and gentle its reentry and landing. Reentry subjected the crew to a full minute of 8 G’s—rather than the customary peak of 4 G’s—and a landing bump of 10 G’s. The capsule landed far afield of its targeted landing site, in an empty field on the Kazakh Steppe, where sparks from the impact started a grass fire.

The Soyuz seats, like race-car seats, have side restraints along the head and the length of the torso. Which makes them safer, unless you need to get out in a hurry. “I had it all planned out,” Expedition 16 commander Peggy Whitson told me in a phone interview. “I’m thinking, ‘I’m going to unstrap and brace my hand here, and then lower my feet,’ and of course none of that worked out. I just fell to the bottom with my head and shoulders in So-yeon’s seat and my legs up and across the hatch.” Gravity was not helping. “After six months, you forget how heavy things are. Like, yourself.” You also, after months of weightlessness, forget how to use your legs. “Your muscles don’t remember what to do.” And astronauts have no pit crew to rush over and help them free of the wreckage.[32] Fortunately, the wind was blowing away from them and the grass fire soon burned itself out.

Worried that NASCAR-style shoulder bolsters might dangerously extend the time it takes an astronaut to get out of the capsule, Gohmert and his colleagues ran some simulations with head bolsters only. For these they used crash test dummies—or “mannequins,” as Gohmert calls them, causing me to picture them taking their hits in department store outfits. It was a bad business. Gohmert described the slow-motion video footage to me. “The head stayed stationary and the body kept moving. We were actually concerned about the mannequin being okay.” As a compromise scenario, the shoulder bolsters are still there but have been scaled down.

NASCAR seats are fitted to each driver, but that’s too expensive to do for each astronaut. The Soyuz seats employ a compromise: a molded seat insert fit to each cosmonaut’s body. But the mold still has to fit inside the seat, which ultimately limits the size of the cosmonaut. “The Russians have a much narrower range of crew sizes,” Gohmert says wistfully. At the time we spoke, seats (and suits) were required to fit bodies that fall anywhere between 1st percentile female to 99th percentile male. That’s 4 feet 9 to 6 feet 6, though standing height is the least of it. A seat system that supports and restrains the entire seated body has to fit buttock-knee lengths from 1st to 99th percentile, and ditto seated chest heights, foot lengths, hip breadths, and seventeen other anatomical parameters.[33]

This wasn’t always the case. Apollo astronauts had to be between 5 feet 5 and 5 feet 10. It was a simple, inflexible cutoff, the governmental version of the sign by the amusement park ride: MUST BE THIS TALL TO RIDE. That meant that a lot of otherwise qualified candidates were kept out of the space program because of their stature. To today’s PC-sensitized mind, that smacks of discrimination.

To Dustin Gohmert, it smacks of common sense. As things stand, NASA has to spend millions of dollars and man-hours making seats lavishly adjustable. And the more adjustable the seat, generally speaking, the weaker and heavier it is.

A further complication for the astronaut, as opposed to the race-car driver: He’s got vacuum cleaner parts attached to his suit[34]—hoses, nozzles, couplings, switches. To be sure the hard parts of a suit don’t injure the soft parts of an astronaut in a rough landing, F will be wearing a suit simulator: a set of rings duct-taped in place around his neck, shoulders, and thighs. The rings are facsimiles of the mobility bearings, or joints, of a spacesuit. (Tomorrow’s cadaver, presently thawing,[35] will be wearing a vest with “umbilicals”—life support hoses and couplings—mounted on it.) One specific concern today is whether, on a sideways touchdown, a mobility bearing might collide with the seat’s shoulder bolster and be driven into the astronaut’s arm with enough force to break a bone.[36]

Gohmert explains how ring joints work, how they enable an astronaut to raise an arm. A pressurized spacesuit is a heavy-duty body-shaped balloon—almost more of a tiny inflated room than an article of clothing. Fully pressurized, it’s all but unbendable without some sort of joints. The current suit prototype has metal shoulder rings that twist back and forth against each other, enabling astronauts to rotate their entire arm up and down, like old-fashioned doll arms. This is my analogy, not Gohmert’s. Earlier in the conversation, I likened NASA’s differently sized, individually selected spacesuit components to the recent development of mix-and-match bikini bottoms and tops. “I haven’t bought one,” Gohmert was careful to point out, “but that sounds right.”

JOHN BOLTE ISN’T 99th percentile, but he’s pretty big. When he drove my crappy little rental car, I swear he had to hunch forward over the steering wheel to fit in it. He was reading texts as he drove, getting updates on the score of his older son’s ball game. I was relatively certain that if he ran off the road, the car would crumple around him and he’d step from the wreckage unfazed, going “Bottom of the eighth, nine to three!”

Bolte has just arrived from OSU, where he runs the Injury Biomechanics Research Laboratory. He’s here to check his students’ work and to help with last-minute preparations before the piston fires. He wears hospital scrubs and a backward baseball cap. He is helping to dress F, pushing the dead man’s fist through the bunched-up sleeve of a long-underwear shirt, a task he likens to dressing his five-year-old.

Now the challenge is to get F into the seat on the sled. Think of wrestling a comatose drunk into a taxicab. Two students hold F’s hips, and Bolte has his hands beneath F’s back. F lies on his back with his bent legs raised, like a man whose dinner chair has tipped over.

The piston is off to F’s right; he’ll be impacted along his lateral axis. “Lateral crashes are very deadly because…” Gohmert stops. “I shouldn’t say crash.” “Landing pulse” is the preferred NASA phrasing. (NASCAR is partial to “contact.”) “NASA must train these guys,” Bolte marveled at one point. “You ask them a question and you see them pause and think through their answer.” Bolte isn’t like that. My favorite line of the day so far has been Bolte’s: “Is he leaking badly from anything major?”

What’s so deadly about lateral “pulses”? Diffuse axonal injury. When an unsecured head whips from side to side, the brain gets slammed back and forth against the sides of the skull. The brain is a smushable thing. It alternately compresses and stretches out as this happens. In a lateral impact, as opposed to a head-on, the stretching pulls on the long neuron extensions, called axons, that connect the brain’s circuits across the two lobes. The axons swell, and if they swell too much, you may go into a coma and die.

A similar thing happens to the heart. A heart, when it’s full of blood, can weigh a good three-quarters of a pound. In a side impact, as opposed to a head-on, there’s more room for it to whip back and forth on the aorta.[37] If the aorta stretches far enough and the heart is heavy with blood at that moment, the two may part ways. “Aortal severation,” as Gohmert put it. This happens less often in a head-on collision, because the chest is relatively flat in that direction; the heart is more sandwiched in place. Hearts also come off their stalk in longitudinal impacts, like those that happen in helicopter drops, because there’s lots of room for them to pull downward and exceed the limits of the aorta’s stretch.

F is finally ready. We’ve moved upstairs to watch the action from the control room. A bank of overhead lights comes on with a dramatic phumph. The actual impact itself is anticlimactic. Because it is air[38] that’s doing the impacting, sled tests are unexpectedly quiet, crashes without a crash. And they are fast, too fast for the eye to register much of anything. The video is shot at ultrafast speed, so that it can be played back in extremely slow motion.

We all lean in to see the screen. F’s arm bends up underneath the shoulder bolster, the space where the rib bolster had been removed. The arm appears to have an auxiliary joint, bending where arms shouldn’t bend. “That can’t be good,” says someone. This has been a recurring problem. As Gohmert puts it: “Gaps in the seat tend to get filled in by body parts.” (The arm will turn out not to be broken.)

F endured a peak impact of 12 to 15 G’s—right on the cusp of injury. Gohmert explains that the extent of an accident victim’s injuries will depend not only on how many G’s of force there were, but on how long it takes the vehicle to come to rest. If a car stops short the instant it hits a wall, say, the driver may endure a split-second peak load of 100 G’s. If the car has a collapsing hood—a common safety feature these days—the energy of those same 100 G’s is released more gradually, reducing the peak force to maybe 10 G’s—highly survivable.

The longer it takes the car to stop moving, the better—with one dangerous exception. To understand it, you need to understand what is happening to a body during a crash. Different types of tissue accelerate more quickly or slowly, depending on their mass. Bone accelerates faster than flesh. Your skull, in a lateral impact, leaves your cheeks and the tip of your nose behind. You can see this in a freeze-frame of a boxer’s face[39] as he’s punched in the side of the head. In a head-on, your frame gets moving first. It’s hurled forward until it’s stopped—by the shoulder belt or by the steering wheel—and then it rebounds backward. A fraction of a second later than your frame began moving forward, your heart and other organs depart. This means that as the heart is launched forward, it collides with the ribcage on its journey back the other way. Everything’s moving forward and back at different rates, colliding with the chest walls and rebounding. And all of this is happening within a few milliseconds. So fast that bouncing and rebounding are the wrong words. Things are vibrating in there.

The big danger, Gohmert explains, is if one or more of those organs starts vibrating at its resonant frequency. This will serve to amplify the vibrations. When a singer hits a note that matches the resonant frequency of a wine glass, the glass starts to vibrate more and more energetically. If the note is sung loud enough and sustained for a long enough time, the glass will shake itself apart. Recall, if you are old like me, the Memorex ads with Ella Fitzgerald and the exploding wine glass. The same sort of thing can happen to an organ that hits its resonant frequency in a crash. It can shake itself off its moorings. And worse. “Essentially,” said Gohmert, after repeated wheedling for specifics, “you’re churned to death.”

You may be wondering: Could Ella Fitzgerald explode your liver? She could not. Glass has a relatively high resonant frequency, up in the audible sound wave range. Body parts resonate down in the long, inaudible wavelength range called infrasound. A launching rocket, on the other hand, creates powerful infrasonic vibration. Could those sound waves shake apart your organs? NASA did testing on this back in the sixties, to be sure, as one infrasound expert told me, “that they didn’t deliver jam to the moon.”

Bolte’s students are sliding F onto a stretcher and loading him into the back of a white van. He’s traveling to the OSU Medical Center where he’ll be scanned and X-rayed. The whole procedure will unfold exactly as it would with a live patient, right down to a forty-five-minute wait and a problem with the billing.

Gohmert’s gaze rests on F. It is hard to read his look. Is he uncomfortable with having had to impact a human body? He turns to Bolte. This I didn’t see coming. “Do you ever put ’em in the front seat and take ’em through the HOV lane?”

I RECALL AN IMAGE from early this morning. Two of Bolte’s students, Hannah and Mike, are standing beside F, talking and laughing as they untangle the long, fine wires that trail from the strain gauges mounted on F’s bones. Rather than seeming gruesome, the scene had a comfortable, familial feel, like a family stringing lights on the Christmas tree. I was struck by how at ease the students were. To them, the cadaver seemed to inhabit an in-between category of existence: less than a person, but more than a piece of tissue. F was still a “he,” but not someone you needed to worry about hurting. Hannah, in particular, had a lovely way with him. While F lay in the CT scanner late that night, an automated recording commanded, “Hold your breath.” “He’s really good at that,” she said. It was funny, but also a sideways acknowledgment of the unusual talents and abilities of the dead.

Not quite so at ease were the NASA team. Outside the context of the testing (and the carpool lane bit), they made very few references to him, and usually with the pronoun it. Getting permission to be here entailed months of emailing with a NASA public affairs officer and culminated in a flurry of tense phone calls upon my arrival this morning. Dead people make NASA uncomfortable. They don’t use the word cadaver in their documents and publications, preferring the new euphemism postmortem human subject (or, yet more cagily, PMHS). In part, I’m guessing, it’s because of the associations. Corpses in spaceships take them to places they’d rather not revisit: Challenger, Columbia, the Apollo 1 fire. And partly, they are unaccustomed to it. I have come across only one project that made use of human cadavers in the past twenty-five years of aeromedical research. In 1990, a human skull rode Space Shuttle Atlantis, kitted out with dosimeters, to help researchers determine how much radiation penetrates astronauts’ heads in low Earth orbit. Worried that the astronauts would be unnerved by their decapitated crewmate, the researchers covered the bone with pinkish plastic molded to approximate a face. “The result was far more menacing than plain bone would have been,” noted astronaut Mike Mullane.[40]

Back in the Apollo era, the agency’s discomfort over using dead people in capsule impact studies appeared to transcend any discomfort they felt about using live ones. In 1965, NASA collaborated with the Air Force on a series of tests very similar to today’s—but with human volunteers. Personnel from Holloman Air Force Base, seventy-nine in all, rode an ersatz Apollo space capsule seat on an impact sled while wearing helmets and other spacesuit components. The men endured 288 simulated splash-downs: upside down and right side up, backward, forward, sideways, at 45-degree angles. Peak forces were as high as 36 G’s, more than twice as powerful as the 12 to 15 G’s inflicted on Subject F today.

Colonel John Paul Stapp, a pioneer in human impact tolerance research, breezily summed up the project in a press release: “It might be said that at the cost of a few stiff necks, kinked backs, bruised elbows, and occasional profanity, the Apollo capsule has been made safe for the three astronauts who will have perils enough left over in the unknown hazards of the first flight to the moon.”

I spoke to a man who rode Holloman’s Daisy sled six times, in various positions, while wearing an Apollo helmet. Earl Cline is sixty-six now. His last ride was in 1966—25 G’s. I asked Cline whether he’d suffered any lasting damage. He replied that he hadn’t had any problems, but as the conversation went on, things began to emerge. To this day, he has pain in the shoulder that bore the brunt of a lateral impact. At the time of his discharge, he was found to have a torn heart valve and one eye that’s “off a little bit.”

Cline reserves his sympathy for the guy whose eardrum ruptured and the one who rode the Apollo seat upside down “with his rear end up in the air” and wound up with a ruptured stomach.

Cline expressed neither resentment nor regret, and has not pursued a disability claim. “I am very proud of the fact that I contributed. I like to think that when they went up in the Apollo missions their helmets didn’t shatter or anything because I tested them.” A subject named Tourville expressed a similar sentiment in a newspaper interview at the time of the Stapp “a few stiff necks” press release: “As long as I know this will save our Apollo astronauts from being hurt on their landings I don’t mind losing sleep with a stiff back for a few days.” Tourville took 25 G’s and suffered a compression injury of the soft tissue surrounding three vertebrae.

Added motivation was provided by a generous hazardous-duty stipend. Bill Britz, a Holloman Air Force Base veterinarian, recalls being paid an extra $100 a month. Cline received $60 to $65 a month for riding the sleds a maximum of three times a week. Given that his base pay was $72 at that time, it was a significant amount. “I lived like an officer,” Cline told me, adding that there was a waiting list to become a Daisy sled volunteer. This was not the case over at Stanley Aviation, in Denver, which NASA had contracted to do some landing impact studies. Capsule mock-ups were hoisted aloft and then dropped onto surfaces of differing compressibility to see what sorts of injuries an astronaut might have to cope with should the capsule go off course and land not on water, but on dirt or gravel or the Winn-Dixie parking lot. There, Britz told me, the pay was only $25. “They got derelicts from Skid Row!” You would think that a news scandal involving underpaid indigents would be a scarier prospect for NASA than one involving cadavers, but things were different back then. The homeless were “derelicts” and “bums,” and cadavers were people who rest on satin pillows.

THE FIRST AMERICAN to live through a space capsule landing mishap endured 3 G’s more than the mission planners had anticipated. His capsule arced 42 miles higher than it was meant to and landed 442 miles off course. By the time rescue ships reached it, two and a half hours later, it had taken on 800 pounds of water and was partly submerged. With great trepidation, the hatch was opened. The space traveler was alive! Upon returning to base, he leapt into the waiting arms of Air Force Master Sergeant Ed Dittmer.

The astronaut was the three-year-old chimpanzee called Ham. (Dittmer was Ham’s trainer.) Ham was more than just the first space capsule landing mishap, of course. He was the first American to ride a capsule into space and come back down alive. As such, he put a bit of a tarnish on the Mercury astronauts’ considerable shine. Ham’s much-publicized flight made it clear to all: The astronaut doesn’t fly the capsule; the capsule flies the astronaut. Along with fellow astrochimp Enos, who orbited Earth three months before John Glenn, Ham was the embodiment of a debate that persists to this day: Are astronauts necessary?