Among the many truly unique technologies created by German scientists during the Second World War, there are many incidents. There is no other name for the "Sun Cannon" project - a colossal orbital mirror that burns entire cities with its beam, evaporates rivers and melts armored vehicles.
During the Second World War, the German village of Hillersleben was the most important training ground where the latest and most advanced weapons were developed. More than 150 engineers and physicists worked in the research centers, creating all kinds of experimental means of warfare, a significant part of which was adopted by the Wehrmacht.
After the surrender of Germany in May 1945, most of the specialists working here had to reorient themselves to more peaceful tasks, leaving a number of projects at various stages of development. Among these projects, one can name a rocket artillery shell with a range 1.5 times higher than analogs that existed at that time; 600-mm cannon, firing shells weighing a ton; the latest modification of the Tiger tank and so on. But perhaps the most ambitious unrealized project remained the Cyclopean Sonnengewehr - "Sun Cannon" - an orbital weapon, the ideal "weapon of retaliation" that Hitler dreamed of in his last years.
The idea for Sonnengewehr came from rocket dad Hermann Oberth. Back in 1929, in the book "The Way to Space Flight" (Wege zur Raumschiffahrt), he proposed a hypothetical manned station, located in orbit about a thousand kilometers above the Earth's surface. Obert described in some detail the possible ways of constructing it from pre-prepared modules (in general, this is how the ISS is going today), proposed using rotation to create an artificial gravitational field, and in general he worked out the concept of periodic support missions for delivering cargo and changing the crew. True, there was nothing particularly bloodthirsty in the physicist's plan: he intended to use such a station as an astronomical observatory and a radio relay, for Earth exploration, rescue missions, meteorology,and only then did he mention defense prospects. But it was they who interested the Reich functionaries.
It was assumed that a concave mirror 100 m in diameter would be placed on board such an orbital station, which would be able to reflect and collect solar radiation to a point on the Earth's surface. Obert believed that this energy could heat water and rotate the turbines of power plants - but the generals preferred to use it literally to burn out everything that met in the path of such an incandescent ray. Agree, it looks more like the designs of the world's villains from American comics!
This idea in itself is far from new. A kind of "sun cannon" was used by Archimedes, who, according to legend, practically destroyed the first wave of the Roman fleet, which in 212 BC. attacked his hometown of Syracuse. According to some testimonies, the brilliant scientist used an array of concave mirrors made of polished copper, burning many enemy ships. Since then, scientists have tried many times to substantiate (or, conversely, refute) the effectiveness of such weapons - and with different results. Not so long ago, this legend was tested for strength by the creators of the cult program "MythBusters" in our edition. They built a set of metal mirrors and found that, in principle, it is possible to set fire to a wooden ship with such a device, but this would require holding the beam at one point for as many as several minutes.which is quite difficult at a distance and when rolling. In short, the veracity of the story of Archimedes the arsonist remains in question. However, let's go back to the XX century.
Using sketches made by Obert, the Hillersleben war-commissioned physicists greatly expanded the concept of an orbiting mirror. They performed the necessary calculations, showing that for their purposes a parabolic mirror with an area of at least 3 sq. km, located at an altitude of 8200 km. The Cyclopean project took 50 years to complete.
After examining a number of reflective materials, it was concluded that metallic sodium, a metal that is quite rare on Earth, would be optimal. This extremely alkaline element, in its pure form, instantly reacts with moisture and oxidizes, however, scientists considered that this did not matter in the rarefied layers of the exosphere. In any case, the choice of sodium remains rather dubious. To put the modules into orbit, it was planned to use the Vergeltungswaffe 2 (V-2), a rather unreliable rocket, with which they tried to bombard London in the last years of the war. A special modified version of it A11 for space launches was even developed by Wernher von Braun in Peenemünde - in theory, such a rocket could deliver a charge through the stratosphere to the American continent itself.
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Inside the station itself, it was planned to generate electricity with special steam generators, heated by all that solar energy. To facilitate work in zero gravity, the "Nazinauts" had to use shoes with magnetic soles, and their exhaled air was continuously regenerated using on-board greenhouses. In them it was possible to breed pumpkins - a plant that absorbs carbon dioxide very actively. To communicate with the command, the Sonnengewehr team had to use an encrypted radio signal, which was already common in those days. Moreover, the "Nazinauts" could not only punish the enemies of the Reich, but also keep them under constant surveillance.
Having received the signal to attack, the team had to launch a whole array of rocket boosters, orienting the mirror in the right direction so that the sun's rays were collected in a small area on the Earth's surface. Theoretically, its energy should have been enough to burn entire cities, evaporate lakes and melt armored vehicles. No country that lacks missile weapons could resist such power.
In the spring of 1945, against the backdrop of an increasingly obvious victory for the USSR and its allies, the project was scrapped. The winners - first of all, the United States - managed to capture a number of the latest technologies that impressed many military and scientists of the time so much that even the “solar sword” did not look like something supernatural in this series. However, many experts were more skeptical. They gave a calculation of the astronomical costs required to deliver hundreds of tons of cargo to orbit, for assembly and equipment - not to mention the cost of the metal itself. There are also doubts that a single mirror is generally capable of collecting enough destructive energy at a focal point located thousands of kilometers from it - unless it will be possible to put a whole set of such mirrors into orbit.
However, the "mirror of Archimedes" has found a lot of more peaceful applications today. Parabolic mirrors that capture sunlight are used for heating food, generating electricity, metalworking, and hydrogen production. The largest of these objects is located in the village of Odeillo in the French Pyrenees: the 8-storey array includes 10 thousand small mirrors, together creating a temperature of 3 thousand degrees Celsius at the focal point.
In reality, this 8-storey building, which includes about 10 thousand separate parabolic mirrors, has become the largest "collector" of sunlight. Today the Solar Oven, built in 1970 in the Pyrenees-Orientales, is the largest in the world. The array of mirrors acts as a parabolic reflector. The light is focused in one center. And the temperature there can reach 3500 degrees Celsius. At this temperature, steel can be melted. But the temperature can be adjusted by setting the mirrors at different angles.