by Kaye Dee

The SEALAB II habitat on the dockside ready for its official launching ceremony

In my article at the end of August about the Gemini 5 mission, I mentioned the unique phone call that Gemini 5 commander Gordon Coper made from space to his fellow Mercury astronaut Scott Carpenter, who was working aboard the SEALAB II experimental underwater habitat. Carpenter is the first astronaut to also serve as an aquanaut, and the two roles are clearly related, since they both involve operations in dangerous, barely explored environments, isolated in small, confined craft. Since the third (and last) crew in SEALAB II has just completed their undersea mission, I thought it would be interesting to look at the SEALAB programme this month.

Getting Saturated

The SEALABs have been developed by the United States Navy to research the technique of saturated diving and enable a better understanding of the psychological and physiological stresses that affect people living in confined isolation for extended periods of time. This research into long-duration isolation is obviously relevant to space exploration as well as undersea activities.

Saturation diving is a technique that reduces the risk of decompression sickness (“the bends”) for divers working at great depths. If a diver breathes inert gasses, while in an environment pressurised to match the intended depth of a dive, the body will become saturated with the gasses, reaching a state of equilibrium once the blood and body tissues have absorbed all they can. Once this occurs, a diver’s decompression time will be the same whether he stays underwater for hours, days, weeks, or even months. This means that if a diver lives in a suitably pressurised habitat, he can work underwater for long periods and only have to undergo decompression once, at the end of his assignment.

The Genesis of SEALAB

SEALAB has its origins in a research programme by Captain George F. Bond, a US Navy physician. In 1957, Dr. Bond began Project Genesis at the Naval Submarine Medical Research Laboratory in Connecticut with the aim of demonstrating that divers could withstand prolonged exposure to different breathing gases at multi-atmosphere pressures. The first two phases of Project Genesis were carried out in 1957 and '58. This involved exposing animals, including rats, goats and monkeys to saturation using a variety of breathing gasses. Dr. Bond happened to meet Jacques Cousteau, the famous French oceanographer, when he gave a talk about the concept of saturation diving in 1957 and the two men became good friends. They co-operated on their diving research, and Cousteau even contributed some ideas to SEALAB II.

"Papa Topside", Dr. George F. Bond, (left) on the SEALAB I support ship with Argus Island in the background

NASA Keeps the Research Going

Despite his promising results, the Navy was not interested in funding the human trials that Dr. Bond needed to progress his research. Then, in 1962, NASA stepped in and funded the human research programme because it was interested in using a mixed -gas spacecraft atmosphere (either nitrogen-oxygen or helium-oxygen) for the Apollo programme – although it has now decided to use a simpler low-pressure oxygen atmosphere for the Apollo spacecraft, despite its potential fire danger.

Between 1962 and 1963, Capt. Bond, with the help of three volunteer divers, experimented with varying gas mixtures of oxygen, nitrogen and helium. One volunteer, Chief Quartermaster Robert A. (“Bob”) Barth took part in all these experiments and went on to become a member of the crews of SEALAB I and II.

"Papa Topside" and SEALAB I

By 1963, Capt. Bond’s team had collected enough data for the Navy to initiate its “Man in the Sea” programme, which would include an experimental habitat, dubbed SEALAB. Dr. Bond serves as the Senior Medical Officer and principal investigator of the SEALAB programme. The SEALAB I crew nicknamed him “Papa Topside”, for being always available on the support ship that kept station above the undersea habitat.

SEALAB I was a cigar-shaped chamber, 40 feet long and 10 feet in diameter. It was constructed from two converted steel floats and held in place with axles from railway cars. The lab had two portholes on each side and two open manholes in the bottom, but water didn’t enter because the pressure inside the chamber was the same as the surrounding water. SEALAB I used a helium-oxygen atmosphere that caused its crew to develop funny, squeaky voices that made them sound like a garbled Alvin the Chipmunk! The habitat was linked to its surface support ship by a Submersible Decompression Chamber, that served as a lift (elevator) between the two. Cables carried electricity, compressed gas, fresh water, communications, and atmosphere sampling lines between SEALAB and the support ship.

The quarters were pretty cramped and uncomfortable on board SEALAB I

First tested in the waters off Panama City, Florida, SEALAB I was lowered to 193ft into the Gulf of Mexico. It was then moved 26 miles southwest of Bermuda and lowered to a depth of 192ft, beside a US Navy research tower named “Argus Island”.

SEALAB I was both a habitability study and an experiment in developing safe decompression procedures for saturation diving. It had a crew of four aquanauts, including former experimental subject Bob Barth. They began their submerged sojourn on 20 July 1964, which was intended to last three weeks. The team investigated the effects of nitrogen narcosis on cognition, tried out the characteristics of the new “Neoprene” foam wet suit and performed many other performed physical and biological experiments. These included using ultrasonic beacons, current meters, and an anti-shark cage, as well as attempting to grow plants in the helium atmosphere.

Unfortunately, the SEALAB I mission had to be aborted after 11 days, due to an approaching hurricane. The support ship attempted to lift the habitat by crane from the ocean floor while slowly decompressing the divers (rising 1 foot every 20 minutes), but the churning sea caused the habitat to sway dangerously back and forth. As a result, the crew were transferred from the habitat to a small emergency decompression chamber and brought to the surface within minutes. 

An amazing underwater shot of the emergency decompression chamber coming to the rescue of the SEALAB I crew

Despite being cut short, SEALAB I was a major success, testing and proving the concept of saturation diving. Many lessons learned from SEALAB I would be applied in the development of its successor-SEALAB II. This included better solutions for raising and lowering the habitat (after two early attempts that dropped it!), lower humidity, improved umbilicals, and a reduction in the gear the divers needed to wear and store in the habitat. A helium voice unscrambler was also developed to improve communications with the aquanauts, because the changes that the gas made in their voices made them almost unintelligible.

The crew of SEALAB I with Mercury astronaut Scott Carpenter, who had originally planned to join their team. (left to right) Gunner's Mate First Class Lester E. Anderson; Lieutenant Robert E. Thompson; Astronaut M. Scott Carpenter, Chief Hospital Corpsman Sanders W. Manning; Chief Quartermaster Robert A. Barth

SEALAB II

SEALAB II is a big advance on its predecessor. Constructed in a naval dockyard in California, it is 57 feet long and 12 feet in diameter, with a small “conning tower”: I’ve heard someone describe it as looking like a “railway tank car, without the wheels”. It has eleven viewing ports and two exits. SEALAB II is also much better equipped, with hot showers, a built-in toilet (I wonder what they used on SEALAB I?), laboratory equipment and a fridge. The gas mixture used onboard is 77-78%helium, 18% nitrogen, and 3-5% oxygen at a pressure of 103 psi, which is seven times that of Earth's atmosphere! SEALAB I found that helium chilled the habitat uncomfortably, so SEALAB II has been fitted with heating coils in the deck to combat the cold. Air conditioning has also been included in this habitat, to reduces the humidity.

A new support ship was provided for SEALAB II, equipped with a Deck Decompression Chamber and a Pressurised Transfer Capsule, used to transport the aquanauts from the surface to the habitat. And, of course, Papa Topside was there, presiding over the experiment.

Inside the Tiltin' Hilton. This team photo of the first SEALAB II crew pokes fun at the habitat's slight tilt. Team leader Scott Carpenter is in the centre of the photo.

In August 1965, the habitat was placed at a depth of 205 feet in the La Jolla Canyon off the coast of California. The location has earned it the nickname of the "Tiltin' Hilton" because it was placed on a sloped part of the ocean floor, giving it a six-degree tilt and a slight cant to port. The first SEALAB II crew, consisting of 10 divers, swam down to the habitat to take up residence on August 28. One of those divers was Mercury astronaut M. Scott Carpenter, who has joined the SEALAB program on leave from NASA.

Astronaut Aquanaut

Carpenter became interested in the SEALAB program after meeting Jacques Cousteau in 1963. He originally planned to be a member of the SEALAB I crew, but was injured in a motorcycle accident during training and so was unable to participate in that experiment. But he became the commander of the first two teams to use SEALAB II, spending 30 days living on the ocean floor. SEALAB II has hosted three crews of ten men, each of 15 days duration. Altogether 28 divers occupied SEALAB II between August 28 and October 10, with Carpenter and Bob Barth both part of two crews.

Originally a Naval aviator, then an astronaut, now Scott Carpenter has added to his resume as the team leader of the first two SEALAB II crews

The SEALAB programme seems to have been a bit jinxed for Carpenter: his right index finger was wounded by the toxic spines of a scorpion fish. In addition to his conversation with Gemini 5, soon after his arrival on SEALAB II, during his time in decompression at the end of his mission, Carpenter also took part in another special telephone call, this time from President Lyndon Johnson. Since Carpenter was calling from a decompression chamber with a helium-oxygen atmosphere, his "chipmunk voice" was almost unintelligible as a helium voice unscrambler was not available! 

The cold water off the Californian coast has been a real test for the aquanauts, along with poor underwater visibility. Even with its heating coils and air conditioning, SEALAB II still experienced high humidity and cold, with the temperature having to be raised to 86°F to ward off the chill. Nevertheless, the aquanauts conducted many physiological experiments and tasks, including testing new tools, methods of salvage and trying out an experimental electrically heated drysuit.

Dolphin Delivery

The Navy Marine Mammal Program also supported SEALAB II, assigning one of its bottlenose dolphins, named Tuffy, to assist the SEALAB crews. Tuffy’s Navy trainers attempted to teach the dolphin useful skills, such as delivering supplies from the surface to SEALAB, or carrying items from one aquanaut to another. Tuffy was apparently not up to the standard of that famous TV dolphin, Flipper, but I’ve heard that he will also be assigned to the SEALAB III mission when that takes place, so the Navy must have been happy enough with his performance.

Tuffy the Navy dolphin, at work during the SEALAB II programme. Wonder if he'll get a TV series of his own some day?

Third time continues the charm?

The third, and last, crew to serve on SEALAB II departed the habitat on October 10, marking the conclusion of a very successful experimental programme. SEALAB I and II have been a resounding success and the knowledge gained from these expeditions will certainly help to improve the techniques of saturation diving and, consequently, the safety of deep-sea diving and rescue. I’ll be watching the future SEALAB III mission, when it arrives, with interest!

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