The Paris Gun 1918: Krupp Shells That Reached the Stratosphere

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At 7:18 in the morning on March 23, 1918, an explosion hit the quai de la Seine in Paris with no aircraft in sight, and 20 more followed at 15 minute intervals. That first day 15 people were killed and 36 wounded, and by March 27 crowds fleeing the city forced the Gare Montparnasse to suspend ticket sales. Theories ranged from silent zeppelins to a cannon hidden in the catacombs, until rifling marks on shell fragments proved the shots came from artillery near Crépy-en-Laon, 120 kilometers away. This was not Big Bertha, the shorter range howitzer used on the Belgian forts in 1914, but a new Krupp weapon built to frighten civilians rather than hit targets.

Engineers under Fritz Rausenberger fitted a 31 meter, 210 mm tube inside worn 38 cm naval gun barrels, producing a 256 ton gun with a 34 meter barrel and a smoothbore section at the muzzle to stop the shell's wobble. Shells left at 1,640 meters per second, rose 42.3 kilometers into the stratosphere and flew for 182 seconds, and Professor von Eberhard calculated for the Earth's rotation by hand. An 80 man naval crew under Vice Admiral Maximilian Rogge fired it while smaller guns masked its sound. The barrel was worn out after 65 shots.

• Each shell was slightly wider than the last, so they had to be fired in exact numerical order or the gun could explode.
• A 106 kilogram shell carried only about 7 kilograms of TNT, because thinner walls would have crumpled in the barrel.
• On Good Friday, March 29, 1918, a shell collapsed the vaulting of Saint-Gervais-et-Saint-Protais, killing 91 worshippers.
• Over its campaign the gun killed 250 people and wounded 620, and the Allies never captured one.
• Versailles limits on artillery pushed Germany toward rockets, and the shell's altitude record stood until the V-2 in October 1942.