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How 'spacewalking' underwater made me feel like I was really in space
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- DeepHorus
An experienced analog mission commander has led SEA STAR, an underwater simulation designed to prepare crews for spacewalks. The commander treated scuba gear as a spacesuit and dive outings as extravehicular activities, or EVAs. Underwater, a serious equipment failure would offer no immediate escape to breathe outside air.
The mission took place at Julesâ Undersea Lab in Florida, where the crew lived 22 feet, or 7 meters, underwater. Before SEA STAR, the commander had led nearly 40 analog missions simulating crewed trips to the moon and Mars. Such missions test isolation, extreme-condition psychology, and technology for lunar or Martian operations.
Spacesuit testing is central to analog work. Fully equipped space suits can weigh about 310 pounds, or 141 kilograms, while analog suits usually weigh no more than 30 pounds, or 14 kilograms. Analog crews can open helmets and breathe outside air if necessary; astronauts and aquanauts cannot.
Aquanauts spend at least 24 hours underwater in saturation, allowing body tissues to absorb the maximum inert gas for a given depth and pressure. Water leaking into suits or the habitat can pose serious risks, along with health problems tied to higher pressures. These dangers required strict protocols before and during underwater EVAs.
The commanderâs caution grew from responsibility for the SEA STAR crew. Scuba equipment failure or decompression sickness can be as lethal as difficulties astronauts face during spacewalks. Although the diving was familiar, leading others made the mission more stressful.
The underwater EVAs still produced lessons for future long-duration space missions. The aquanaut âspacesuitsâ were essentially scuba gear, with two important accessories not always needed on normal dives. Such analog missions help researchers identify equipment and safety improvements before astronauts travel farther from Earth.
