Command and Control (6 page)

The silo door motors on level 1A had to be checked, as did the sump at the bottom of level 9B, and everything in between. The equipment areas of the silo tended to be loud, but the launch duct was lined with sound dampeners, so that the roar of the engines wouldn't cause vibrations and damage the missile. It was so quiet in the launch duct that on hot summer days, when the air-conditioners were struggling, warm oxidizer could be heard bubbling in the tanks. The only problem that Holder and Fuller noted that day was a faulty switch on the hard water tank. The complex had two large water tanks: one inside the silo, extending from levels 3 to 6, and one topside beyond the perimeter fence. The tank within the silo was considered “hard” because it was underground, and therefore shielded from a nuclear blast. It held one hundred thousand gallons of water that would spray into the silo moments before launch. The water helped to suppress the sound of the engines and ensured that flames wouldn't rise up the silo and destroy the missile. The two water tanks were also essential for extinguishing a major fire at the complex. Like a broken float in a toilet that allows only one flush, a faulty switch on the hard water tank could prevent it from refilling automatically. Holder and Fuller noted the problem on the checklist and moved to the next step.

PTS Team A reached the complex around 3:30 in the afternoon, but the platforms still wouldn't lower. Having nothing better to do, the team hung out and played cards around the table in level 1 of the control center. Jeffrey Plumb, who was new to the group, lay on one of the beds. They'd been working since early in the morning and were ready to be finished
with the day. PTS teams and launch crews didn't tend to socialize. The PTS guys were a different breed. Outside of work they had a reputation for being rowdy and wild. They had one of the most dangerous jobs in the Air Force—and at the end of the day they liked to blow off steam, drinking and partying harder than just about anyone else at the base. They were more likely to ride motorcycles, ignore speed limits, violate curfews, and toss a commanding officer into a shower, fully clothed, after consuming too much alcohol. They called the missiles “birds,” and they were attached to them and proud of them in the same way that good automobile mechanics care about cars. The danger of the oxidizer and the fuel wasn't theoretical. It was part of the job. The daily risks often inspired a defiant, cavalier attitude among the PTS guys. Some of them had been known to fill a Ping-Pong ball with oxidizer and toss it into a bucket of fuel. The destruction of the steel bucket, accompanied by flames, was a good reminder of what they were working with. And if you were afraid of the propellants, as most people would be, you needed to find a different line of work.

Although low pressure in an oxidizer tank could mean a leak, PTS Team A wasn't worried about it. This was the third day in a row that they'd been called out to 4-7. The missile in the silo had recently been recycled. The warhead and the propellants were removed during a recycle, and then the missile was lifted from the silo, hauled back to the base, carefully checked for corrosion and leaks. Later, the same missile might be returned to the complex, or a different one might be shipped there from storage. The fuel and oxidizer pressure often didn't stabilize at the proper levels for weeks after a recycle. PTS teams were accustomed to adding more nitrogen two, three, four times until the tank pressures settled.

At the conclusion of the recycle at 4-7, a Titan II was placed in the silo, filled with propellants, and armed with a warhead.
The missile's serial number was 62-0006. The same missile that had been in the silo during the fire at the complex near Searcy now stood on the thrust mount at Launch Complex 374-7 north of Damascus. The odds were slim that the same Titan II airframe, out of dozens, would wind up in those two places.
Bad luck, fate, sheer coincidence—whatever the explanation, neither the launch crew, nor the PTS team, knew that this missile had once been in a silo full of thick smoke and dying men.

By six o'clock in the evening, the platforms had finally been repaired, and the PTS team was ready to do its work. Childers was in the control center, instructing the trainee. Mazzaro and Heineman, the PTS team chief, were there as well, going over the checklist for the procedure. Holder decided to get a few hours of sleep. Although the control center was underground and far removed from the world, it was always noisy. Motors, fans, and pumps were constantly switching on and off. Test messages from SAC were loudly broadcast over the speakers, and telephones rang. The sound had nowhere to go, so it bounced off the walls. Holder never slept well there, even with earplugs. The vibration bothered him more than the noise. The whole place was mounted on springs, and there was so much machinery running that the walls and the floors always seemed to be vibrating. It was the sort of thing you didn't notice, until you became perfectly still, and then it became hard to ignore.

Holder took off his socks and shoes, put on a T-shirt and some pants from an old uniform, and had a bite to eat before bed. He was washing dishes when the Klaxon went off. The sound was excruciatingly loud, like a fire alarm, an electric buzzer inside your head. He didn't think much of it. Whenever a nitrogen line was connected to an oxidizer tank, a little bit of vapor escaped. The vapor detectors in the silo were extremely sensitive, and they'd set off the Klaxon. It happened almost every time a PTS team did this procedure. The launch crew would reset the alarm, and the Klaxon would stop. It was no big deal. Holder kept doing the dishes, the Klaxon stopped—and then ten or fifteen seconds later it started blaring again.

“
Dang,” Holder thought, “why'd that go off again?” He heard people scurrying on the level below and wondered what was going on. He went halfway down the stairs, looked at the commander's console, and saw all sorts of lights flashing. He thought the PTS team must have spiked the MSA—the vapor detector manufactured by the Mine Safety Appliances Company. If the MSA became saturated with too much vapor, it spiked,
going haywire and setting off numerous alarms. That didn't mean anything was wrong. But it did mean one more hassle. Now the crew would have to conduct a formal investigation with portable vapor detectors.

Holder went back upstairs and grabbed his boots. When he came down again, Captain Mazzaro was standing and talking on the phone to the command post in Little Rock. Childers was giving orders to the PTS team topside. Something wasn't right. Holder sat at the commander's console and looked down at rows of red warning lights.
OXI VAPOR LAUNCH DUCT
was lit.
FUEL VAPOR LAUNCH DUCT
was lit.
VAPOR SILO EQUIP AREA, VAPOR OXI PUMP ROOM,
and
VAPOR FUEL PUMP ROOM
were lit. He'd seen those before, when an MSA spiked. But he'd never seen two other lights flashing red:
FIRE FUEL PUMP ROOM
and
FIRE LAUNCH DUCT
. Those were serious. There's a problem, Holder thought. And it could be a big one.

I
n the old black-and-white photograph, a young man stands at the bedroom door of a modest home. He wears khakis and a white T-shirt, carries a small metal box, and doesn't smile for the camera. He could be a carpenter arriving for work, with his lunch or his tools in the box. A cowboy hat hangs on the wall, and a message has been scrawled on the door in white chalk: “
PLEASE USE OTHER DOOR—KEEP THIS ROOM CLEAN.
” The photo was taken on the evening of July 12, 1945, at the McDonald Ranch House near Carrizozo, New Mexico.
Sergeant Herbert M. Lehr had just arrived with the unassembled plutonium core of the world's first nuclear device. The house belonged to a local rancher, George McDonald, until the Army obtained it in 1942, along with about fifty thousand acres of land, and created the Alamogordo Bombing and Gunnery Range. The plutonium core spent the night at the house, guarded by security officers. A team of physicists from the Manhattan Project was due at nine o'clock the next morning, Friday the thirteenth. After billions of federal dollars spent on this top secret project, after the recruitment of Nobel laureates and many of the world's greatest scientific minds, after revolutionary discoveries in particle physics, chemistry, and metallurgy, after the construction of laboratories and reactors and processing facilities, employing tens of thousands of workers, and all of that accomplished within three years, the most
important part of
the most expensive weapon ever built was going to be put together in the master bedroom of a little adobe ranch house. The core of the first nuclear device would be not only home made but hand made. The day before, Sergeant Lehr had sealed the windows with plastic sheets and masking tape to keep out the dust.

Although the question of how to control an atomic bomb had inspired a good deal of thought, a different issue now seemed more urgent: Would the thing work? Before leaving Los Alamos, two hundred miles to the north, some of the Manhattan Project's physicists had placed bets on the outcome of the upcoming test, code-named Trinity. Norman F.
Ramsey bet the device would be a dud. J. Robert Oppenheimer, the project's scientific director, predicted a yield equal to 300 tons of TNT; Edward Teller thought the yield would be closer to 45,000 tons. In the early days of the project, Teller was concerned that the intense heat of a nuclear explosion would set fire to the atmosphere and kill every living thing on earth. A year's worth of calculations suggested that was unlikely, and the physicist Hans Bethe dismissed the idea, arguing that heat from the explosion would rapidly dissipate in the air, not ignite it. But nobody could be sure. During the drive down from Los Alamos on Friday the thirteenth, Enrico Fermi, who'd already won a Nobel for his discoveries in physics, suggested that the
odds of the atmosphere's catching fire were about one in ten. Victor Weisskopf couldn't tell if Fermi was joking. Weisskopf had done some of the calculations with Teller and still worried about the risk.

As Louis Slotin prepared to assemble the plutonium core, the safety precautions were as rudimentary as the work space. Jeeps waited outside the house, with their engines running, in case everyone had to get out of there fast. Slotin was a Canadian physicist in his early thirties. For the past two years at Los Alamos he'd performed some of the most dangerous work, criticality experiments in which radioactive materials were brought to the verge of a chain reaction. The experiments were nicknamed “
tickling the dragon's tail,” and a small mistake could produce a lethal dose of radioactivity. At the ranch house, Slotin placed a neutron initiator, which was about the size of a golf ball, into one of the plutonium hemispheres, attached it with Scotch tape, put the other hemisphere on top, and sealed a hole with
a plutonium plug. The assembled core was about the size of a tennis ball but weighed as much as a bowling ball. Before handing it to Brigadier General Thomas F. Farrell, Slotin asked for a receipt. The Manhattan Project was an unusual mix of civilian and military personnel, and this was the nation's first official transfer of nuclear custody. The general decided that if he had to sign for it, he should get a chance to hold it. “
So I took this heavy ball in my hand and I felt it growing warm,” Farrell recalled. “I got a sense of its hidden power.”

The idea of an “atomic bomb,” like so many other technological innovations, had first been proposed by the science fiction writer H. G. Wells. In his 1914 novel
The World Set Free
, Wells describes
the “ultimate explosive,” fueled by radioactivity. It enables a single person to “
carry about in a handbag an amount of latent energy sufficient to wreck half a city.” These atomic bombs threaten the survival of mankind, as every nation seeks to obtain them—and use them before being attacked. Millions die, the world's great capitals are destroyed, and civilization nears collapse. But the novel ends on an optimistic note, as fear of a nuclear apocalypse leads to the establishment of world government. “
The catastrophe of the atomic bombs which shook men out of cities . . . shook them also out of their old established habits of thought,” Wells wrote, full of hope, on the eve of the First World War.

The atomic bombs in
The World Set Free
detonated slowly, spewing radioactivity for years. During the 1930s, the Hungarian physicist Leó Szilárd—who'd met with H. G. Wells in 1929 and tried, without success, to obtain the central European literary rights to his novels—conceived of a nuclear weapon that would explode instantly. A Jewish refugee from Nazi Germany, Szilárd feared that Hitler might launch an atomic bomb program and get the weapon first. Szilárd discussed his concerns with Albert Einstein in the summer of 1939 and helped draft a letter to President Franklin D. Roosevelt. The letter warned that “
it may become possible to set up a nuclear chain reaction in a large mass of uranium,” leading to the creation of “
extremely powerful bombs of a new type.” Einstein signed the letter, which was hand delivered to the president by a mutual friend. After British researchers concluded that such weapons could indeed be made and
intelligence reports suggested that German physicists were trying to make them, the Manhattan Project was formed in 1942. Led by Leslie R. Groves, a brigadier general in the U.S. Army, it secretly gathered eminent scientists from Canada, Great Britain, and the United States, with the aim of creating atomic bombs.

Conventional explosives, like TNT, detonate through a chemical reaction. They are unstable substances that can be quickly converted into gases of a much larger volume. The process by which they detonate is
similar to the burning of a log in a fireplace—except that unlike the burning of a log, which is slow and steady, the combustion of an explosive is almost instantaneous. At the point of detonation,
temperatures reach as high as 9,000 degrees Fahrenheit. As hot gases expand into the surrounding atmosphere, they create a “shock wave” of compressed air, also known as a “blast wave,” that can carry tremendous destructive force. The air pressure at sea level is 14.7 pounds per square inch. A conventional explosion can produce a blast wave with an air pressure of
1.4 million pounds per square inch. Although the thermal effects of that explosion may cause burns and set fires, it's the blast wave, radiating from the point of detonation like a solid wall of compressed air, that can knock down a building.

The appeal of a nuclear explosion, for the Manhattan Project scientists, was the possibility of an even greater destructive force. A plutonium core the size of a tennis ball had the potential to raise the temperature, at the point of detonation, to
tens of millions degrees Fahrenheit—and increase the air pressure to
many millions of pounds per square inch.

Creating that sort of explosion, however, was no simple task. The difference between a chemical reaction and a nuclear reaction is that in the latter, atoms aren't simply being rearranged; they're being split apart. The nucleus of an atom contains protons and neutrons tightly bound together. The “binding energy” inside the nucleus is much stronger than the energy that links one atom to another. When a nucleus splits, it releases some of that binding energy. This splitting is called “fission,” and some elements are more fissionable than others, depending on their weight. The lightest element, hydrogen, has one proton; the heaviest element found in nature, uranium, has ninety-two.

In 1933, Leó Szilárd realized that bombarding certain heavy elements with neutrons could not only cause them to fission but could also start a chain reaction. Neutrons released from one atom would strike the nucleus of a nearby atom, freeing even more neutrons. The process could become self-sustaining. If the energy was released gradually, it could be used as a source of power to run electrical generators. And if the energy was released all at once, it could cause an explosion with temperatures many times hotter than the surface of the sun.

Two materials were soon determined to be fissile—that is, capable of sustaining a rapid chain reaction: uranium-235 and plutonium-239. Both were difficult to obtain. Plutonium is a man-made element, created by bombarding uranium with neutrons. Uranium-235 exists in nature, but in small amounts. A typical sample of uranium is about 0.07 percent uranium-235, and to get that fissile material the Manhattan Project built a processing facility in Oak Ridge, Tennessee. Completed within two years, it was
the largest building in the world. The plutonium for the Manhattan Project came from three reactors in Hanford, Washington.

A series of experiments was conducted to discover the ideal sizes, shapes, and densities for a chain reaction. When the mass was too small, the neutrons produced by fission would escape. When the mass was large enough, it would become critical, a chain reaction would start, and the number of neutrons being produced would exceed the number escaping. And when an even larger mass became supercritical, it would explode. That was the assumption guiding the Manhattan Project scientists. In order to control a nuclear weapon, they had to figure out how to make fissile material become supercritical—without being anywhere near it.

The first weapon design was a gun-type assembly. Two pieces of fissile material would be placed at opposite ends of a large gun barrel, and then one would be fired at the other. When the pieces collided, they'd form a supercritical mass. Some of the most difficult computations involved the time frame of these nuclear interactions. A nanosecond is one billionth of a second, and the fission of a plutonium atom occurs in ten nanoseconds. One problem with the gun-type design was its inefficiency: the two pieces would collide and start a chain reaction, but they'd detonate before most of
the material had a chance to fission. Another problem was that plutonium turned out to be unsuitable for use in such a design. Plutonium emits stray neutrons and, as a result, could start a chain reaction in the gun barrel prematurely, destroying the weapon without creating a large explosion.

A second design promised to overcome these problems by increasing the speed at which a piece of plutonium might be made supercritical. The new weapon design was nicknamed, at first, “
the Introvert.” A sphere of plutonium would be surrounded by conventional explosives. The shock wave from the detonation of these explosives would compress the sphere—and the denser the sphere became, the more efficiently it would trap neutrons. “
The more neutrons—the more fission,” a secret government manual on nuclear weapons later explained. “
We care about neutrons!” Imploding a ball of plutonium to produce an explosion was a brilliant idea. But it was easier said than done. If the conventional explosives failed to produce a shock wave that was perfectly symmetrical, the plutonium wouldn't implode. It would blow to pieces.

Many of the physicists who worked on the Manhattan Project—Oppenheimer, Fermi, Teller, Bethe—later became well known. And yet one of the crucial design characteristics of almost every nuclear weapon built since then was perfected by George B. Kistiakowsky, a tall, elegant chemist. Born in the Ukraine and raised in an academic family, Kistiakowsky had fought against the Bolsheviks during the Russian civil war. He later earned a degree at the University of Berlin, emigrated to the United States, and become a professor of chemistry first at Princeton, then at Harvard. By the mid-1940s, he was America's leading expert on explosives. Creating a perfectly symmetrical shock wave required not just the right combination of explosives but also the right sizes and shapes. Kistiakowsky and his team at Los Alamos molded explosive charges into three-dimensional lenses, hoping to focus the shock wave, like the lens of a camera focuses light. Tons of explosives were routinely detonated in the hillsides of Los Alamos, as different lens configurations were tested. Kistiakowsky considered these lenses to be “
precision devices,” not crude explosives. Each weighed between seventy and one hundred pounds. As the date of the Trinity test approached, he spent long hours at the lab with a
dentist's drill, eliminating the air bubbles in lenses and filling the holes with molten explosives. The slightest imperfection could distort the path of a shock wave. The final design was a sphere composed of thirty-two shaped charges—twelve pentagons and twenty hexagons. It looked like a gigantic soccer ball and weighed about five thousand pounds.

The shape and composition of the explosive lenses were irrelevant, however, if the lenses failed to detonate at exactly the same time. The shock wave would travel through the device at a speed of one millimeter per millionth of a second. If a single lens detonated a few ten millionths of a second before the others, it could shatter the plutonium without starting a chain reaction. Blasting caps and Primacord were the detonators usually employed with conventional explosives. But both proved incapable of setting off thirty-two charges simultaneously. The physicist Luis Alvarez and his assistant, Lawrence Johnston, invented a new type of detonator for the job—
the exploding-bridgewire detonator. It sent a high-voltage current through a thin silver wire inserted into an explosive. The current vaporized the wire, created a small shock wave, and detonated the explosive. Donald F. Hornig, who was one of the youngest scientists at Los Alamos, devised a contraption, the X-unit, that could store 5,600 volts in a bank of capacitors and then send that electricity instantaneously to all the detonators.