NASA's engineers developed a number of high-tech new machines, scattered at military bases across the nation, that would simulate aspects of what the astronauts would likely confront during space flight. And that became the driving theory behind the astronauts training regimen:
Excerpted from: "Light This Candle: The Life and Times of Alan Shepard, America's First Spaceman." Copyright 2004 by Neal Thompson. Published by Crown Publishers, New York, New York. Portions have been edited for context.
to build machines that re-created the excruciating tremors and pressures of sitting on the nose of a rocket traveling faster than any human had ever traveled; to mimic the weightlessness the astronauts would experience in outer space; to simulate the sensation of tumbling through space in a disabled and out-of-control capsule.
The training program sprang from all the what-ifs that the engineers and scientists had posited. Because, in truth, the experts weren't too sure what would happen to a man in space; opinions ranged from "nothing" to "disgusting, painful death."
So, to cover all their bases, the engineers decided to explore each what-if and then see if the astronauts could survive an approximate duplication of that scenario. When they weren't in classrooms learning about astrophysics, geophysics, and astronomy, the astronauts were flying from city to city, allowing themselves to be subjected to heat chambers, pressure chambers, a "rotating room," and other of NASA's noisy, dangerous, gut-sloshing experimental training contraptions.
"There was always another what-if," (John) Glenn once remarked, referring to the nervous Nellies in NASA's medical corps who dreamed up many ghastly scenarios. What if the astronauts experienced "separation anxiety" and inexplicably refused to return to Earth? What if the astronauts' eyeballs oozed and became misshapen in the zero gravity of space? What if the fluids of the inner ear, which control balance, floated out of the astronauts' heads, leaving them permanently dizzy and vertiginous?
And what if the astronauts' orbiting space capsule spun out of control? To prepare for the off chance of such a scenario, the brilliant minds of NASA created MASTIF - the multiple axis space training inertial facility. Similar to a gyroscope, MASTIF was an enormous set of three concentric cages, called gimbals, one inside each other. Each cage was a misshapen, geometric skeletal box that looked as though it'd been assembled from the leftover parts of a set of playground monkey bars.
The outer cage was red, and inside that was a smaller green cage, both of them vaguely circular. At the center was a yellow cage, roughly cone-shaped, to represent the astronauts' space capsule. And at the center of the yellow cage was a cockpit where the astronaut sat, strapped in tight. Each gimbal was hinged to the next, but they all rotated independently from each other and in different directions, so that the cockpit could be programmed to spin - just like the Mercury capsule might in space - on three axes: pitch (from front to back), roll (side to side), and yaw (from left to right, in a twisting motion).
The engineers could program the machine to rotate just one of the cages, which would cause the astronaut's capsule to simulate a side-to-side pitching motion. Then the programmers could rotate two of the cages, causing the astronaut's cockpit to pitch and spin simultaneously. Finally, they could rotate all three cages, simulating a completely out-of-control capsule, tumbling and spinning and yawing through space.
The astronauts had to learn to use a hand control - similar to the control stick in a jet - that released spurts of gas that acted as a brake against the rotating motion of the gimbals. The goal was to stop the cockpit from tumbling and bring it to a complete stop.
Shepard intended to be the first to master MASTIF. But in a flashback to his downcheck during flight training at Corpus Christi and the two near-fatal crash dives at Edwards Air Force Base, he was immediately, frighteningly humbled.
The practice sessions began slowly, with just one or two of the cages spinning at modest speeds, and Shepard was able to quickly stop the cockpit from tumbling. But when he first gave the thumbs-up for the technicians to spin all three cages, and also increase the speed - each gimbal was capable of up to thirty revolutions per minute - things got ugly.
As the cages spun faster and faster, their breezelike whooshing sound rose into a piercing scream. After just a minute or two, with Shepard's body being tossed front to back and side to side, he reached out and slammed the red "chicken switch" button, which set off a loud klaxon that told the technician to shut down the machine.
The cages stopped tumbling, and engineers helped a dizzy and nauseated Shepard from the cockpit and led him to the cot they kept nearby - with a mop and a bucket beside it, just in case. But Shepard was determined to master the thing.
He got back in it that afternoon and performed a little better, but still had to punch the chicken switch, and so he decide to quit for the day. A few of the doctors on hand the first day were surprised at how long it took Shepard to recover from his dizziness and nausea.
The next morning he strapped himself in again. And the next. Within a few days he was able to withstand the full thirty revolutions per minute in each axis. He learned how to quickly and accurately twist and turn the control stick until he stopped one gimbal, then the next and then the next, bringing the cockpit to a standstill.
In one of the 35 mm films NASA took of the training sessions, Shepard emerged from a session in MASTIF, then stopped and stared back at the machine, the disgust plain on his face. Then he lifted his head as if to say, I beat you, you mechanical freak, turned, and walked out, chin in the air, chest out.
Another machine - the one that Shepard despised the most - was the centrifuge outside Philadelphia. It was a small flying-saucer-shaped capsule at the end of a fifty-foot arm that spun in a tight circle, like a tree-sized croquet mallet being swung by a giant.
The sadistic purpose of the machine was to expose the astronauts to the type of excessive gravity, or G forces, that they'd experience riding atop a launching rocket. They would be traveling faster than any human had flown, and the doctors had to determine whether their bodies could take the strain.
One G is the equivalent of the Earth's gravitational pull. Two Gs is essentially gravity times two. So under two Gs of gravitational pressure, a 175-pound man would feel as if he weighed 350. As the centrifuge rotated faster and faster, the astronauts would be pushed into their couches beneath hundreds of pounds of pressure, pummeled by G loads more excruciating than any fighter pilot had ever felt.
NASA engineers calculated that during their explosive launch from Earth, the astronauts would experience at least five or six Gs - the equivalent of about half a ton of pressure for a 175-pound man.
But there were unanswered questions about how many Gs they'd experience during their capsule's plunge from the emptiness of space to the thick, friction-inducing air of the Earth's atmosphere. Ten? Fifteen? No one knew for sure, so the doctors decided to give the astronauts a taste of the worst.
At five or six Gs in the centrifuge, it was still possible - but just barely - for the astronauts to lift their arms and flip a few switches on the mock dashboard in front of them. At seven Gs they were slammed into the couch and incapable of movement, as if bags of cement had been stacked on their chest, legs and arms. They had to tense their muscles to keep the blood from draining out of their head and causing them to black out.
With some practice, they reached inhumane G loads of sixteen; the record, achieved (on a dare) by an unassuming Navy lieutenant, was an astonishing 20 Gs. Such spins would smoosh back the skin on their face like Play-Doh. After such sessions, they'd find their backs splotched and red from broken blood vessels.
As if such spinning wasn't bad enough, NASA engineers then devised an even more gruesome exercise with the centrifuge. They had asked themselves: What if the astronaut's capsule lands on its nose, instead of its behind? To test their assumptions, the engineers decided to measure the astronaut's capacity for "reverse Gs."
While the centrifuge arm was spinning and the astronaut was being shoved back into his contour couch, the engineers would rotate the capsule 180 degrees so that the man inside was abruptly thrown into his should straps.
They called it the EI/EO test, for "eyeballs in, eyeballs out," which is exactly what happened. Shepard once told a reporter that it was a "real pleasure" to go from spinning forward to backward. But Glenn wasn't the only one who found the test "sadistic."
One of NASA's doctors tried the EI/EO and emerged hacking uncontrollably, unable to catch his breath; through some testing the other doctors determined that his heart had slammed into one of his lungs and deflated it.
On May 5, 1961, Alan Shepard became the first American in space. Long after this historical flight, Shepard started to experience episodes of extreme dizziness and nausea. Some of these episodes were so severe that he would fall to the ground and vomit. Although he kept this condition quiet for some time, he was eventually diagnosed with Ménière's disease, where fluids were building up in the semi-circular canal of his left inner ear.
He was scrubbed from future missions; everyone imagined that he might fall off the moon ladder, puncture his suit, and be the first astronaut casualty. Successful surgery allowed him to finally fly again - on Apollo 14, when he hit the golf ball on the moon.
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