Where Have All the Aquanauts Gone? The Story of Sealab

By: Jesslyn Shields  | 
sealab 2, oceanography
Sealab II, built on the design of Sealab I, which included multiple chambers and a dedicated support ship, was submerged at a depth of 205 feet (62 meters) near La Jolla, CA in August 1965. Wikimedia Commons

Even though around 70 percent of our planet is covered in saltwater, we have a better map of Mars than we do the oceans that sustain virtually every living thing on Earth. Sure, ocean exploration is expensive and complicated, but so is space exploration, and we do plenty of that.

There was a time, though, during the early years of space exploration, that aquanauts were pushing the limits of how deep humans could dive under the ocean, and how long they could stay down there. Sealab, a program launched by the U.S. Navy in 1964, was intended to figure out how to send divers down into the freezing, high-pressure environments of the deep sea for longer periods of time than anyone ever thought possible. And the program was a big success, until it wasn't anymore.


Humans Underwater

It's always challenging to get a human body free-swimming at any great depth, the reason being that our bodies are not made to withstand millions of gallons of water piled on top of us. Divers have to breathe pressurized air, which contains inert gases — nitrogen, mainly — that dissolve into the bloodstream and tissues, which works out great so long as the weight of the entire ocean keeps them compressed. If a diver wants to come up to the surface, she must do it slowly in order to avoid the gases making little bubbles in her blood, migrating to her joints and causing decompression sickness (or, "the bends"), which is unspeakably painful, and sometimes fatal.

In the early 1960s, a Navy physician named George Bond figured out how to let people explore the ocean in a way nobody ever thought possible through a technique called saturation diving. In his laboratory experiments, Bond was able to saturate the blood with inert gases like helium in such a way that divers could not only go deep, they could stay down indefinitely, so long as they had the right set-up and a shelter. Divers could become acclimated to a habitat 200 feet (60 meters) below the surface and free dive even deeper from there.


"Dr. Bond's breakthroughs were a little bit like the diving equivalent of breaking the sound barrier," says Ben Hellwarth, author of "Sealab: America's Forgotten Quest to Live and Work on the Ocean Floor." "It was a quantum leap in technology over what the diving parameters had been for more than a century."


Sealab I, the first iteration of the Sealab experiment, was housed in a 57-foot-long (17 meters) steel tube lowered onto the ocean floor off the coast of Bermuda in July of 1964, at a depth of 192 feet (59 meters). Four men successfully stayed submerged in this pod for 11 days, and the experiment went so well that Sealab II was submerged off the coast of La Jolla, California at a depth of 205 feet (62 meters) in August of the next year. Sealab II had hot showers, a refrigerator and a dolphin named Tuffy, trained to deliver supplies and rescue aquanauts, if necessary. After a 30-day stay on Sealab II, aquanaut (and astronaut!) Scott Carpenter spoke to President Lyndon Johnson from his helium-atmosphere decompression chamber sounding like a cartoon chipmunk. He might have sounded ridiculous, but history was made: he had survived a month at a pressure of 103 psi, which is seven times that of Earth's atmosphere.

"I want you to know that the nation's very proud of you," President Johnson told Carpenter.


It's strange, then, that only a few years later, an accident on Sealab III, which was situated on the seafloor off the coast of San Clemente, California at a depth of 600 feet (183 meters), could have shut the program down. But when aquanaut Berry Cannon went down to fix a carbon monoxide leak on the still-uninhabited Sealab III and died of asphyxiation, the Navy shut the program down in short order.

"Most people involved were aware that this was a dangerous operation — they always knew it had been," says Hellwarth. "Sealab I and Sealab II had gone well, with no major injuries. After the tragedy on Sealab III, they all expected to press on, but the Navy didn't see it that way, so the program was canceled. It was still a low-profile enough program that there wasn't a national uproar about giving up the race to the bottom of the ocean that you would expect if they had tried to cancel the space program two years earlier after the Apollo I launchpad fire that killed three astronauts. I think everyone expected the program to go on, but for various reasons it didn't."


The Legacy of Sealab

We still use the technical breakthroughs George Bond pioneered with the Sealab program, mostly in the oil industry, setting up oil platforms. Saturation divers can go to a job site hundreds of feet below the surface and stay down there for an entire eight-hour shift.

"Unbeknownst to most people, we all owe the fuel in our tank to some extent to some saturation diver working out in the Gulf of Mexico or the North Sea," says Hellwarth.


But George Bond's vision was not just industrial — it was military, civilian and scientific. He solved the problem of going deeper and staying longer, but after Sealab was canceled, it turned out that industry is where the money was. Any military application — equipping military submarines to release saturation divers as spies during the Cold War, for instance — would be highly classified, and therefore hard to document.

But there is one place on Earth where a Sealab-type facility still exists for scientific research: the Aquarius Reef Base south of the Florida Keys, that's been in operation for over 20 years. Scientists can go down there, 60 feet (18 meters) below the surface, and live anywhere from a few days to a couple weeks, running experiments on the reef.

"Dr. Bond's vision was science-related," says Hellwarth. "He thought we ought to have Sealab-like bases set up in the ocean wherever there might be something of interest to study and observe. We should get to know that environment better because there's value to spending time in the ocean, just like there was value in Jane Goodall's being able to sit and observe in the jungle. Once you're down there and can stay awhile, you really don't know what you're going to see. That's how we discover things."

Learn more about Sealab in "Papa Topside: The Sealab Chronicles of Capt. George F. Bond, USN" by Helen A. Siiteri, ed. HowStuffWorks picks related titles based on books we think you'll like. Should you choose to buy one, we'll receive a portion of the sale.


Frequently Answered Questions

Where is Sealab II?
Sealab II is located in the Pacific Ocean, off the coast of California.