The Sun Gun: The Nazi Plan to Build an Orbital Death Ray

The Sun. Naturally, someone looked up and wondered "Can I kill somebody with that?"

The Sun. Naturally, someone looked up and wondered “Can I kill somebody with that?”
Image Credit: NASA

Death rays are the stuff of comic books and B-grade sci-fi movies, usually wielded by cacklng mad scientists in an attempt at world domination. While they are normally considered the stuff of fiction, real scientists (I’ll leave it up to you to decide if they’re mad or not) have tried to develop their own versions of the fictional weapon. Tesla worked on a machine that could use electricity to make a particle beam and Archimedes allegedly built a solar death ray to combat the Romans.

Not to be outdone, the Nazis too had plans on the book to build a solar death ray, the Sun-Gun. Now the Nazis were no strangers to cartoon-ish supervillainy, their plans for the Sun-Gun really took the cake. In fifty to one hundred years, the Nazis wanted to build an orbital super weapon that could scorch cities to the ground and boil oceans.


Planned in every detail

By the time the Allies learned of the Sun Gun plan, Nazi Germany was in ruins and the US and Soviet Union were in a mad dash to acquire Germany’s so-called “wonder weapons.” The Nazis were able to construct the world’s first ballistic missiles and functional jet fighters, weapons the Allies couldn’t match. So when technical experts came across the plan for an orbital death ray, it seemed chillingly plausible.

The weapon had its origins in the work of Dr. Hermann Oberth, a German engineer and rocketry pioneer. He developed detailed plans for an orbital space station in the 1920s. This space station would be used as a jumping off point for further exploration of the solar system, and beyond.

Hermann Oberth

Hermann Oberth

The Nazis looked at Oberth’s plan and decided to weaponize it by building a giant mirror out of sodium, which could be used to focus solar radiation into a pin point on the Earth’s surface. The highly focused energy would act essentially like a giant laser, able to vaporize anything it was aimed at. Such a weapon would be impossible to combat; any gathering of strength could be targeted from on high and burned to a cinder before an attack could be mounted. It would also be a weapon of terror that could be used to assure Nazi dominance of the Earth. No one would be too enthusiastic about mounting an assault on the Nazi Empire when their cities and people could be vaporized, after all.

In order to build the orbital monstrosity, the Nazi scientists working on the project envisioned using rockets to lift prefabricated sections into orbit. Once the station was built, it would house operators who lived and worked on the station. Pumpkin patches would be established on the station, primarily in order to produce oxygen. Pumpkin seeds and other supplies would be brought up by rocket, and dock by thrusting through a thirty foot hole in the station’s structure. Workers living on the station would have to wear magnetic shoes, because there would be no gravity on the station (the Nazis were apparently pragmatic enough to realize that artificial gravity was beyond their reach.) The whole station would be moved into position by strategically placed miniature rockets, and the sodium mirror would be built in segments to best be able to move it into position to fire.

The Nazis were playing the long game in planning the Sun Gun. They recognized that the technology did not yet exist to build the weapon. Their best rocket, the infamous V-2, would not have been able to reach the 5100 mile orbit called for in the plan by itself, much less with enough payload to begin building the mirror. In addition, the technology required for orbital construction would need to be worked out. So, the scientists working out these plans hoped that it might be able to be put into play within the next fifty or one hundred years, presumably after the Nazi Empire had spread over a significant portion of the planet.

Unfortunately for them, and fortunately for the rest of us, the Thousand Year Reich came to a fiery end after less than two decades.


A feasible weapon?

The ISS. Currently, this is the largest human made object orbiting Earth. It is a LOT smaller than the Sun Gun would have been.

The ISS. Currently, this is the largest human made object orbiting Earth. It is a LOT smaller than the Sun Gun would have been.

While the empire that planned the Sun Gun went up in flames, the weapon itself remains an intriguing possibility. Would it have been possible to have built such a space station, and would it have been a workable weapon even if it could have been built?

A station the size of the Sun Gun would have been a mammoth undertaking.The exact size of the planned station is unclear. The mirror alone could have been hundreds or even thousands of meters in diameter. That does not include life support systems, living space, storage space, and other additions.

Using the minimum time span projected by the planners, the space mirror should have been built by about the mid 1990s. In 1998, NASA and the Russian space agency embarked on the initial construction of the International Space Station, a cooperative project between several of the world’s space agencies. At 239 feet in length and weighing 990,000 pounds sixteen years after its initial launch, the ISS is the largest artificial object in orbit. It is only a fraction of the size the Sun Gun would need to be in order to function properly as a living station and a weapon. So, while that does not show that the Sun Gun would have been impossible, even now it remains outside of our technological reach. This does not even take into account the economic and political realities that would be involved in such a project. No doubt, the Sun Gun would be the biggest engineering feat in human history, and would require unprecedented international cooperation to achieve.

So, the construction of the weapon isn’t impossible, but could the Sun Gun really be used as a weapon? It turns out that a quirk of optics mean that rather than destruction from on high, the sun gun would probably unleash nothing more horrifying than a pleasant spring day. This is because of the distances involved. Using a magnifying glass to fry ants works because the glass is held close, which results in a smaller area of focus and thus enough heat to be deadly (or to light a fire in a survival situation.) Pulling back the magnifying glass would widen the focal point and decrease the intensity of the radiation. A similar principle would be at work with the Sun Gun. At 5100 miles up, the focal length would be too large to produce intense enough heat to destroy anything, let alone an entire city or army.

In the end, the Sun Gun remains little more than a historical curiosity, another one of those grand ideas from the last century that turned out, for one reason or another, to be unworkable.



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