Joachim Ronneberg, The Resistance Fighter Who Sabotaged Nazi Nuclear Weapons, Dies At 99

Published October 22, 2018
Updated December 19, 2018

"We were a gang of friends doing a job together. We very often thought that this was a one-way trip."

Joachim Ronneberg Portrait

Maruricio Lima for The New York TimesJoachim Ronneberg in 2015.

Joachim Ronneberg, a Norwegian¬†resistance fighter who led the successful 1943 mission to sabotage the Nazis’ plans for an atomic bomb, has died at the age of 99.

Ronneberg was only 23-years-old when he spearheaded the mission that would change the world’s future. He was the last living member of the team of resistance fighters that infiltrated a Nazi nuclear facility and successfully destroyed it from within before the Nazis even knew what had hit them.

Born in 1919 in Aalesund, Norway, Ronneberg was 21-years-old when the Nazi invasion of 1940 forced him to flee his home country. Ronneberg joined a group of friends to escape to Scotland, but never forgot about their homeland.

Meanwhile, Nazi Germany had nuclear plans. The Reich was in the process of creating an atomic bomb and required a substance called heavy water in order to finish it. Heavy water contained an extra atomic particle in its nucleus which made it an essential ingredient in building a nuclear bomb.

Inside Vemork

FlickrInside the Vemork heavy water plant, now a museum.

The only place that made large enough amounts of heavy water to make a bomb was Norsk Hydro facility in Rjukan, Telemark, Norway. A plan, called Operation Gunnerside, was subsequently launched to destroy the heavy water stores and thus the Nazis hopes of creating the first atomic bomb.

But the facility was deep underground and fortified by bomb-proof material which made destruction by air raids impossible. So a British team of 35 men was first sent to infiltrate the facility and destroy it from the inside. But this had ultimately failed.

23-year-old Ronneberg then was tapped to lead the next perilous mission into enemy territory. Under the endorsement of Winston Churchill himself, Ronneberg and eight comrades armed with cyanide tablets in case of capture embarked on what they thought would be a life-ending journey.

“We were a gang of friends doing a job together,” Ronneberg told the BBC in 2013. “We very often thought that this was a one-way trip.”

Joachim Ronneberg Young

The AustrailianA young Joachim Ronneberg in uniform.

To simply enter the plant was treacherous. The young men had to carefully parachute into the area, ski across the country in frigid temperatures, descend into a ravine, and cross a river to get into the basement to set their explosives. But Ronneberg managed to push his men through.

By the time the surrounding German guards heard the explosions and understood what had happened, it was too late. Ronneberg and his men had fled the facility. 3,000 German soldiers chased the mission, but Ronneberg’s team escaped to nearby Sweden by cross-country skiing for nearly 200 miles.

“It was the best skiing weekend I ever had,” Ronneberg quipped.

Ronneberg added that at the time, he and the team did not truly understand the impact of their mission. He said that it was not until after the war had ended that he understood.

“The first time I heard about atomic bombs and heavy water was after Americans dropped the bomb on Hiroshima and Nagasaki,” Ronneberg told the New York Times in 2015. He added that if the Germans would have gotten their hands on an atomic bomb during World War II, London would have ended up “looking like Hiroshima.”

With Ronneberg’s passing, the world loses one of its greatest remaining World War II heroes. But the impact of his legacy and bravery will live on forever.

Next, read up on other World War II heroes like: Freddie Oversteegen, the Dutch resistance fighter who seduced and killed Nazis as a teen, and also Witold Pilecki, the Polish resistance leader who voluntarily entered Auschwitz to be the first tp expose its horrors to the world.

Caroline Redmond
Caroline is a writer living in New York City who holds a Bachelor's in science from the University of Florida. Her work has appeared in People, Yahoo, Bustle, Entertainment Weekly, and The Boston Herald.
Leah Silverman
A former associate editor for All That's Interesting, Leah Silverman holds a Master's in Fine Arts from Columbia University's Creative Writing Program and her work has appeared in Catapult, Town & Country, Women's Health, and Publishers Weekly.
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Redmond, Caroline. "Joachim Ronneberg, The Resistance Fighter Who Sabotaged Nazi Nuclear Weapons, Dies At 99.", October 22, 2018, Accessed May 23, 2024.