Deep-sea diving: A stricter test for the body than space travel
A short trip to space poses less of a challenge to the human body than diving to great depths, assessed Professor Jacek Kot, an expert in hyperbaric medicine from the Medical University of Gdańsk.
On 10 June, the Ax-4 space mission will launch from Kennedy Space Centre in Florida, featuring Polish astronaut Sławosz Uznański-Wiśniewski. The crew also includes Peggy Whitson from the USA, Shubhanshu Shukla from India, and Tibor Kapu from Hungary. Interestingly, deep-sea diving would present a greater challenge for the entire crew than the impending space flight.
Stay on Earth's orbit less demanding on the body
"For a healthy person, a short stay in orbit is physiologically less demanding than deep diving. If an astronaut on the International Space Station has an accident, they can be brought back to Earth within a few days. In contrast, safely retrieving a saturated diver from a depth of even 330 feet requires decompression that can last up to a week," said PAP hyperbaric medicine expert Professor Jacek Kot.
The expert explains that space medicine has always profited from insights in diving medicine, particularly concerning the body's tolerance to pressure changes. Nowadays, thanks to technological advancements, atmospheric pressure similar to Earth's is maintained in manned space missions.
Challenges related to decompression
Today, as described by Professor Kot, an astronaut experiences pressure changes primarily in two situations: when there is a cabin leak or during spacewalks, when wearing a suit, where the pressure must be reduced to allow for unrestricted movement. "This requires appropriate preparation, similar to the decompression process for divers," explained the professor.
Saturated divers working under increased pressure require 100–200 hours of decompression to surface from a depth of 330 feet safely. In cases of serious injuries, such as a heart attack, they can only reach the hospital after a few days.
Such significant pressure changes do not occur during space flights
"In diving, every 10 metres of depth corresponds to an increase in pressure by one atmosphere," explained Professor Kot. He added that "at a depth of 330 feet, the pressure is ten times higher than at the surface." He emphasised that such significant pressure changes are not experienced during space flights.
During diving, regular air mixtures become dangerous even at moderate depths. Excess oxygen damages the lungs, and nitrogen causes effects similar to alcohol intoxication. Professional divers use gas mixtures tailored for specific depths, yet even these mixtures pose a risk of decompression sickness when surfacing.
As Professor Kot highlighted, diving to great depths remains a greater challenge today than a journey to orbit. "Space is fascinating, and its exploration is difficult, but diving is even harder and more taxing on the body," the researcher concluded.
