Graham Hawkes and the Race to the Bottom of the Sea
Credit: Balint Porneczi / Bloomberg / Getty Images

Hawkes finally made the inaugural trip in Deep Flight I in 1996, with a test dive in California's Monterey Bay, proving that the concept of underwater flight would work as he'd promised. But to actually reach Challenger Deep, he'd need a craft capable of diving far deeper. A plan for Deep Flight II was already on his drawing board, ready to go: a full-ocean-depth craft to carry two people. He estimated he would need another $3 million to finish it. There were no takers until, four years later, Steve Fossett called.

That first conversation, in 2000, was awkward. "Very stiff," Hawkes says. "We were circling one another." Finally, Fossett explained what he wanted: to set the record as the first man to travel alone to Challenger Deep. Hawkes had an idea: What about a flying submarine? Fossett agreed. "Finally," Hawkes thought at the time, "someone who will foot the bill. Let's do it!" There was, of course, a problem. Hawkes visualized building a pair of flying submersibles to make the dive together – for safety and so that they could film one another during the journey. Fossett insisted on one submarine, to carry a single person: Steve Fossett. "Steve took this very seriously," Hawkes says. "People who set records parse things." He asked Fossett if he would be able to use the submarine after the record had been broken, to visit Challenger Deep himself. It was, after all, the goal of almost everything he had worked on for nearly 15 years. There was, Hawkes recalls, a long silence on the line.

"No," Fossett told him. "I set the record – it goes in the Smithsonian."

"And I said, 'Well, Steve, I don't think we've got much to talk about.' "

And that was it for another four years, during which time Hawkes repeatedly tried and failed to raise the money to make the dive himself, and Fossett – on his sixth attempt – became the first man to make an uninterrupted circumnavigation of the globe by balloon.

At the end of 2004, Hawkes finally gave in. At the library of the adventurer's estate in Carmel, California, they struck a deal: In exchange for building a single submarine that would make a single trip to full ocean depth and secure Fossett the title of Deepest Man on Earth, Hawkes would retain the intellectual property of his design.

The engineer worked closely with Fossett on the project for years but found his motives inscrutable, and they never became friends. "I admired the guy," Hawkes tells me. "But we didn't get on." The machine Hawkes built for him was stripped down and austere, engineered from materials on the outer limits of experimental technology. At Fossett's insistence, safety margins and equipment were shaved to make savings in both cost and weight; Hawkes, once again, scavenged for parts. In May 2007, DeepFlight Challenger was undergoing final testing in the Applied Research Laboratory Building at Penn State when, subjected to the 16,000 pounds per square inch of pressure it would endure at the bottom of the ocean, the glass viewing dome of the submarine cracked – the result of a manufacturing fault. By now, Fossett had spent $3 million on the project and wanted to see a swift return on his investment; he became ever more deeply involved in micromanaging the work. By the end of August 2007, the submarine was weeks away from sea trials. Then, at 8:45 on Labor Day morning, Fossett climbed into his single-engine Super Decathlon in the Nevada desert, taxied down the runway, and vanished into the sky.