While Apollo 9 astronauts were preparing for outer space, two crews of U.S. aquanauts began new missions to determine how well man can exist in inner space—the underwater depths.
Near San Clemente Island off the California coast, the Navy's trouble-plagued "yellow submarine," Sealab 3, was lowered 610 ft. to the floor of the continental shelf. Then instruments indicated a helium leak in the still-unoccupied deep-sea habitat, and Aquanaut Berry L. Cannon, 33, and two companions were sent below to make repairs. They descended to the 610-ft. level in a pressurized personnel transfer capsule (PTC) and were opening a hatch to enter Sealab when Navy officers watching a TV monitor on the surface saw Cannon begin to thrash about. "I saw his body jackknifing, making a rapid motion," says Captain George Bond, Sealab's chief medical officer. "Any time you see rapid motion in a diver, you know he's in trouble." Cannon died before he could be brought to the surface.
Series of Leaks. Late in the week a Navy investigation revealed that "one of the diving rigs in use by Sealab divers was equipped with an empty Bar-alyme canister." Without the Baralyme, which absorbs carbon dioxide exhaled by the diver, the gas builds up in the system and can eventually cause suffocation. "This could explain the tragic event," said a Navy spokesman, and indeed, an autopsy revealed "a greatly excessive" amount of carbon dioxide in Cannon's blood. Navy officials ordered a halt to all diving. Sealab 3, still leaking helium, was brought to the surface and lifted onto a barge to be taken ashore and repaired.
The tragedy marked still another lengthy setback for the Sealab project, which is already about two years behind schedule. Designed to help man learn the techniques and develop the equipment that will enable him to live and work for long periods under the sea, the project has been beset by delays. First there was a steel strike; then some of the steel that was delivered turned unexpectedly brittle at low temperatures. Redesign of the oxygen system was called for after the fatal Apollo fire, and that was followed by a series of seawater and helium leaks. At week's end no one would predict how long it will be until Sealab is again judged seaworthy.
A few days after other aquanauts set up housekeeping aboard Tektite, a second undersea habitat that had been lowered into Lameshur Bay at St. John, V.I., one of four fire extinguishers began to leak carbon dioxide into the cabin. It was quickly placed outside. The following day, the unit that had detected the carbon dioxide ceased to function. But Tektite technicians began hourly atmosphere checks to ensure the safety of the aquanauts and expressed confidence that their mission would continue successfully for its scheduled two-month duration. If everything goes according to plan, the aquanauts hope to complete underwater biological and geological studies, learn more about diving and sonar techniques and supply medical and behavioral data that will help scientists plan the longer manned space flights of the future.