The High Pressure Experiments That Made D-Day
Fresh Air
NPR
4.3 • 36.1K Ratings
🗓️ 14 November 2025
⏱️ 45 minutes
🧾️ Download transcript
Summary
What happens to the body in the deep sea? You need oxygen to survive, but too much oxygen can be deadly. If you rise to the surface too quickly, nitrogen bubbles can form in your body and kill you. Terry Gross spoke with author and scientist Rachel Lance last year about her research for the military. She used a hyperbaric chamber that mimics what divers and submarines are exposed to. Her book, ‘Chamber Divers,’ is about the scientists whose dangerous experiments about underwater pressure and injury were critical to the success of D-Day.
Also, Justin Chang reviews ‘Sirat,’ which he calls one of the most gripping movies of the year.
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Transcript
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| 0:00.0 | This is Fresh Air. I'm David B. and Cooley. Veterans Day has us thinking about our interview from last |
| 0:06.0 | year about some brave and obsessive scientists. Before and during World War II, they did underwater |
| 0:12.6 | research, which was essential to the success of D-Day. When Allies had to conduct surveillance, |
| 0:18.8 | searching for traps and mines underwater and on the shore before storming the beach at Normandy. |
| 0:24.5 | We're going to listen back to Terry's interview from last year with Rachel Lance. |
| 0:28.9 | She wrote the book titled Chamber Divers, the untold story of the D-Day scientists who changed special operations forces forever. |
| 0:40.1 | She's a biomedical engineer and blast injuries specialist. Some of her research revolves around the questions, how can the human |
| 0:45.9 | body survive the extremes of the deep sea? And how do blasts and bombs underwater affect the body |
| 0:52.8 | compared to the impact of blasts on land. |
| 0:55.7 | For several years, Rachel Lance was an engineer for the U.S. Navy, |
| 1:00.0 | researching and testing new underwater technology for Navy divers, seals, and Marine Force recon personnel. |
| 1:07.5 | She also conducted research at Duke University using their hyperbaric chamber. |
| 1:12.5 | That's an enclosed chamber in which the air pressure can be increased or decreased, |
| 1:16.8 | along with the levels of oxygen and other gases, to simulate the extremes of underwater environments, |
| 1:22.6 | monitor the negative impact on the human body, and test solutions. |
| 1:27.2 | In order to do the research, the scientists during |
| 1:30.1 | World War II put themselves through extremes in the hyperbaric chamber and sustained some fairly |
| 1:35.5 | serious injuries. Rachel Lance, welcome to Fresh Air. What were you researching that made you |
| 1:41.7 | interested in the World War II underwater research? |
| 1:45.8 | I read this paper about carbon dioxide, and it wasn't extremely exciting. |
| 1:52.1 | It concluded essentially that carbon dioxide is bad for you, and it hurts, which I already knew. |
| 1:57.0 | But something about the date bothered me. |
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