The Day We Lost the H-Bomb: Cold War, Hot Nukes, and the Worst Nuclear Weapons Disaster in History

the USS Thresher, and asked for assistance. Andrews had retired from the Navy but was happy to help. He suggested that Craven call Wagner Associates, a small consulting firm outside Philadelphia. Soon Dan Wagner, the owner of the company, was flying to Washington with a member of his staff, a probability expert named Tony Richardson.

In Washington, Craven briefed the two mathematicians on the situation and gave Richardson a rough

“probability map” that he had sketched. The map, which showed the area off the coast of Palomares, resembled a contour map. However, the contours on Craven's map showed not the height of a mountain ridge or the depth of an ocean trench but the probability that the bomb had fallen into certain points in the sea. Craven hadn't had much information when he had drawn the map, so his initial stab basically outlined what everyone already thought: that the bomb lay either right off the beach or somewhere near the fishermen's sighting. Craven gave Tony Richardson a copy and sent him and Frank Andrews to Spain.

On the plane to Madrid, Richardson sat next to Andrews and discussed his strategy, sketching out ideas on graph paper. He knew basically how to run a systematic search — mathematicians had been working on search theory since at least World War II. First he had to develop a probability map laying out where the bomb might be hiding. Second — this was the tough part — he had to find a way to evaluate the search as the Navy carried it out. And not just say “good” or “bad” but quantify the search, evaluate it mathematically. Then, as the search continued and new information came in, he would update the probability map, hopefully narrowing down the search area. Richardson could keep the analysis going until the Navy found the bomb or gave up the search.

On the plane, Richardson explained his system to Andrews. He thought he could call it “search failure probability.” In other words, after the Navy had searched a given area, this was the probability that the bomb was there but the Navy had failed to find it. Andrews shook his head.

Tony, he explained, you have it all backwards. You are dealing with the Navy. You can't talk about failure! You need to talk about success. Richardson objected, showing Andrews a sample probability he had plotted on his graph paper. Andrews looked at it and frowned. The line that Richardson had drawn sloped downward toward the bottom of the page. It looked like a business with a bad quarter or a stock market crash. No, no, no, Andrews explained. In the Navy, graphs need to point up.

Richardson and Andrews reported to Admiral Guest on February 22. Richardson's reputation had preceded him. The ship had prepared for the arrival of the distinguished mathematician, assigning him a generous stateroom with a private sink and stewards. So Guest was a bit taken aback to discover that Dr. Richardson was a baby-faced twenty-seven-year-old who looked even younger than his age.

Eyeballing this new member of his team, Guest asked Dr. Richardson what he could do for the mission. Richardson launched into a description of his plan — now called search effectiveness probability — and an explanation of Gaussian probability distributions. As Guest's eyes glazed over, Andrews stepped in and cut Richardson off. After the admiral escaped, Andrews turned to Richardson. Would this kid ever learn? “Tony,” he said, “don't talk about Gaussian distributions to an admiral!” Later, Guest pulled Frank Andrews aside. “Where the hell did you get this high school kid?”

Soon, however, Guest began to see the value of his new addition. Richardson, working with the grid overlay of the search area, assigned each square a “search effectiveness probability” (or “SEP”) number between 0 and 1. A low number, close to 0, meant that if the bomb lay in that square, searchers probably wouldn't have found it yet, either because they hadn't searched there or because they hadn't used the proper tools. A higher number, such as.95 or.98, meant that if the bomb rested in that area, the searchers probably would have found it by now. The goal was to get each square on the grid from a low number to a higher one.

Some on the task force had doubts about Richardson's system. After all, the information he used to make calculations was vague. Nobody could say for sure when Alvin or Aluminaut or OBSS had

“covered” a particular area, because their navigation accuracy and the underwater terrain remained largely unknown. But Richardson had equations to cover these uncertainties. Every night, he crunched numbers using a Frieden calculator — a mechanical adding machine the size of a cash register — in the Boston's accounting office. Because the office was busy during the day, Richardson made all his calculations from about 11 p.m. to 3 a.m., the chug-chug-chug of the calculator keeping him company. At eight every morning, he presented his new chart to Guest at the admiral's daily briefing.

Guest grew to love Richardson's search effectiveness probability chart. Like all salvage missions, the search for the missing bomb was a succession of failures, one day after another of hard work, with nothing to show for it. Richardson's ever-changing numbers were the only tangible sign of progress. “It's important psychologically to have something that shows that you're actually achieving something. And SEP served that purpose,” said Richardson. “It was kind of like the thermometer on the United Fund chart. It keeps going up and up.”

That is to say, the numbers in certain squares kept going up and up; namely, those searched by Red Moody's inshore divers — probably the only searchers on Task Force 65 properly trained and equipped to do their job. By February 17, they had thoroughly scanned the water from the beach out to eighty feet deep. “He had guys swimming along the shore that were actually looking at the bottom with their eyes,” recalled Richardson. “So I'd always have these very high numbers for Red, like over ninety percent.” The numbers cheered Admiral Guest, not only because they showed progress but because he could then tease Red Moody, the towering, muscular diver, about intimidating the skinny mathematician into fixing his stats.

Deep water, however, was another story. With Alvin, Aluminaut, and OBSS struggling, the numbers in the deepwater boxes remained stubbornly close to zero. At times, Guest moved the submersibles inshore, probably to be able to check off a few more boxes on Richardson's chart. The submersible crews, with no understanding of the admiral's motivations, were greatly annoyed by these seemingly arbitrary moves. But the admiral didn't care, because he was greatly annoyed by the submersibles.

By the time Alvin and Aluminaut had been in Spain for a few weeks, specific grievances began to emerge. During a dive on level terrain, Aluminaut veered off her back-and-forth sweep pattern to examine what appeared to be a piece of airplane wreckage. The crew took photos and presented them to Guest at a meeting on the flagship. Instead of being congratulated on the find, as he expected, Art Markel received a rebuke. “What are you doing, going out of the area?” demanded Guest. “I think I'll have to send you back to the States, because you don't know how to take orders.” Markel, proud of his work and his ship, was furious.

The Alvin crew had its own problems with the admiral. The high seas had led to several close calls for the little sub. On February 23, the waves rose too high for the crew to maneuver Alvin into the well deck of the Fort Smiling, so the Navy ship used its crane to lift Alvin over the side. It was a risky maneuver, dangling the fragile sub close to the side of the ship, and Earl Hays did not want to repeat it. He would not risk Alvin or her crew by diving in rough weather again and sent a message to the flagship stating so.

Soon after, Hays attended a briefing on the flagship. Guest told the scientist that he wanted Alvin to dive by 2 p.m. the following day. Knowing Alvin would dive only if the weather permitted, Hays replied, “Maybe I will, maybe I won't.” Guest, taken aback by the scientist's insolence, asked what he meant. Hays, equally insulted by Guest's demand, replied, “If you're going to give me orders like that, Admiral, I'm going to take Alvin and go home.” With that, Guest threw Hays out of the room.

Then he turned to Brad Mooney, who had witnessed the exchange, and said, “What the hell do you do with a guy like that?”

Mooney, used to dealing with both admirals and scientists, knew that the two men came from vastly different cultures, one that demanded obedience and one that questioned authority. But Mooney also knew that no matter what their differences, these people had to work together to find the bomb. He said to Guest, “Admiral, he's a researcher. Why don't you not talk to him anymore and let me talk to him?” From that day on, says Mooney, Guest never spoke to Earl Hays. Such events soured the already strained relationship between Guest and the Alvin crew. Some of the crew understood the admiral, but many, according to Mooney, just “locked into their minds what a bastard Guest was.” By the end of February, Guest had all the deep-search tools he was going to get. Despite the personnel difficulties, Aluminaut and Alvin were diving and searching. The USNS Mizar had arrived,