Mary Roach - Packing for Mars

Getting back to weightlessness. Weight is a bit of a mind-bender. I had always thought of my weight, on any given day, as a constant, a physical trait like my height or my eye color. It’s not. I weigh 127 pounds on Earth, but on the much smaller moon, whose gravitational pull is one sixth of Earth’s, I weigh about as much as a beagle. Neither weight is my real weight. There is no such thing as a real weight, only real mass. Weight is determined by gravity. It’s a measure of how fast you’ll accelerate if you happen to be dropping through the air like Newton’s apple. (Here on Earth, were there no atmospheric drag to slow you down, gravity would accelerate you at the rate of 22 miles per hour faster for each second that you fall.) If you’re standing on the ground, you obviously don’t speed up, but the pull is still there. You’re not falling, just pressing. The acceleration reads as weight on a bathroom scale. When there’s nothing to press against, as in the free fall of orbit, then you are weightless. The “zero gravity” that astronauts experience aboard an orbiting spacecraft is simply a continuous state of falling around the Earth.

If something provides a supplemental source of acceleration—something added to the acceleration prompted by Earth’s gravity—now your weight will change. Take your bathroom scale into an elevator and watch the readout as you take off. You will briefly gain weight, and perhaps a minor reputation around the building. The elevator’s acceleration has added an extra earthward pull to the earthward pull of gravity. Contrariwise, when the elevator approaches the top floor and slows down, the deceleration renders you briefly lighter; it has accelerated you skyward, counteracting some of the Earth’s downward pull.

Why is there this force, this pull between objects? Poking around on the Web for a suitably patient entity to ask, I came upon the Gravity Research Foundation, founded by multimillionaire businessman and fire alarm magnate Roger Babson. After gravity pulled Babson’s sister toward the bottom of a river and she drowned, he became history’s most voluble antigravity activist, publishing screeds like Gravity: Our Enemy No. 1. If I were Babson, I might have nominated water or currents for the number-one spot, but the man was unshakable in his ire. [15] To inspire future generations to take up the fight against gravity, Babson paid for stone monuments to be erected at thirteen prominent American colleges. Colby College’s “antigravity stone,” as it became known, states its goal as follows: “To remind students of the blessings forthcoming when a semi-insulator is discovered in order to harness gravity as a free power and reduce airplane accidents.” The students were differently inspired: In what became a joyous progravity rite, the antigravity stone was knocked over so many times that the college eventually relocated it to a less prominent spot. Along with the stones, Babson left the colleges small grants but did not explicitly state that the money must go toward antigravity research. Loath to sponsor “Mickey Mouse” science, Colby used the money to erect a skyway connecting two science buildings. “At least,” noted a college spokesperson, “it’s off the ground.”

Babson is dead, but the foundation lives on. It no longer characterizes its efforts as antigravity, a term that has come to connote “crackpot.” “We are neither ‘pro-gravity’ nor ‘anti-gravity,’” director George Rideout, Jr., told a journalist who profiled the organization in 2001. They are, he said, just trying to learn as much as possible about it. I contacted Rideout seeking an explanation of why gravity exists. He told me to go ask a physicist.

I did. I made a hobby of it. But why are two masses drawn together, I’d say. “Mary, Mary, Mary,” was the kind of response I tended to get. “Because space-time exists,” said one physicist. “What does ‘why’ mean?” said another. Perhaps gravity is a mystery even to those who understand it. I can well imagine that the prospect of messing with it must have been daunting to the pioneers of aerospace medicine out in the desert in 1948.

DISMAYED BUT UNDETERRED, Simons and his crew launched four more Alberts. Albert III’s rocket exploded. Alberts IV and V were, like Albert II, victims of malfunctioning parachute systems. Albert VI made it to the ground with his vital signs little changed, but died of heat prostration while rescuers searched for the nose cone. Eventually the Air Force—and you do wonder what took them so long—stopped naming their ill-fated gravity monkeys Albert. More importantly, they began to move away from the V-2s in favor of a smaller, less problematic [16] The V-2’s directional system was notoriously erratic. In May 1947, a V-2 launched from White Sands Proving Ground headed south instead of north, missing downtown Juarez, Mexico, by 3 miles. The Mexican government’s response to the American bombing was admirably laid back. General Enrique Diaz Gonzales and Consul General Raul Michel met with United States officials, who issued apologies and an invitation to come to “the next rocket shoot” at White Sands. The Mexican citizenry was similarly nonchalant. “Bomb Blast Fails to Halt Spring Fiesta,” said the El Paso Times headline, noting that “many thought the explosion was a cannon fired for the opening of the fiesta.” rocket called the Aerobee.

Patricia and Michael, in 1952, were the first monkeys to survive a trip to Weightlessville. The macaques’ heart rate and breathing was monitored throughout the flight and appeared to be normal. Biomedical research from this era appears to have been fixated on pulse and respiration. Publicity images from that era invariably show a physician in a white coat and crewcut, holding a stethoscope to a monkey’s narrow chest. That’s all the Albert papers reported on. You couldn’t diagnose much from it— yep, still alive —but this was the limit, circa 1950, of the data you could transmit back from a rocket 30 or 50 or 80 miles up. To rule out any subtler effects of weightlessness, the Air Force would need a subject they could interview: a human. For that, they needed a safer way to go about it.

It was a team of brothers, Luftwaffe aerospace medicine pioneers Fritz and Heinz Haber, who, in 1950, dreamed up a technique known today as parabolic flight. The Habers theorized that if a pilot flies the same kind of parabolic arc as a suborbital rocket (or a baseball pop fly), then the passengers, for anywhere from 20 to 35 seconds at the top and the downward segments of the arc, will experience weightlessness, just as the monkeys had. If the pilot then pulls out of the downward dive and heads back up and repeats the process, over and over until his fuel runs low, science will have an accumulation of several minutes of weightlessness to work with—at a fraction of the cost of building and launching rockets. These roller-coaster zero-gravity flights are still flown today by space agencies to test equipment or train astronauts or humor authors who have pestered them ceaselessly for months (more on this shortly).

Here the scene shifts to South America. The Habers had a colleague named Harald von Beckh, who lived in Buenos Aires after the war. Von Beckh knew from the V-2 and Aerobee rocket flights that weightlessness posed no grave threat to survival, but he wondered whether it would disorient a pilot or otherwise compromise his ability to fly a craft. So naturally, von Beckh went out and got some snake-necked turtles. Hydromedusa tectifera are, like post-war Nazis, native to Argentina, Paraguay, and Brazil. These are turtles that hunt like snakes, coiling their overlong necks into an S and then unwinding in bullet-fast strikes that rarely miss. That is what von Beckh planned to test. Would weightlessness put them off their game? It did. The turtles moved “slowly and insecurely” and did not attack a piece of bait placed directly in front of them. Then again, the water in which they swam was repeatedly floating up out of the jar and forming an “ovoid cupola.” Who could eat?