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Project Orion: America’s Cold War Plan for Nuclear-Powered Space Exploration

OK, hear me out. What if we could design a spacecraft that was not propelled by traditional rocket fuel. Instead, what if we could harness the awesome power of a nuclear explosion to power our rockets in space? If that sounds about as far fetched as Donald Trump becoming President back in 2014 – then you’re in for a real surprise. 

Starting in 1958, Project Orion was a study in the United States to explore this very possibility. Not to give the game away too early here, but it was a plan that never came to fruition, because of several issues that we will get to later in the video.

It’s important to remember that we are looking back at this 60 years later, with a very different idea of what nuclear energy can do. At the time this new form of energy was still in its relative infancy, and governments around the world were eager to harness its astonishing, yet terrifying power. We love to tell people to think outside of the box – well, this was about as outside of the box as you were going to get. Even to this day debate continues about the feasibility of the whole project. Was it an absurd vision, or missed opportunity?  


While the first nuclear reaction didn’t take place until 1942, the concept of a rocket-powered by the combustion of some kind of explosive substance was first mentioned in 1881 by a Russian by the name of Nikolai Kibalchich – and please bear with me while I put Project Orion on hold for a moment because this man has a hell of a story.

Nikolai Kibalchich was just 27 years old when he took part in the assassination of the King of Russa, Alexander II in St Petersberg. His role as the main explosives expert for the revolutionary group, ‘the people’s will’, which had carried out the attack, led to his arrest on 17th March 1881. 

I probably should have already mentioned that while he was certainly involved in the assassination, he was also a brilliant, rocket pioneer. The speed of the trial process was incredibly fast, and Kibalchich was soon sentenced to hang – but his work in this life was not quite done. 

Scribbling away in his cells, he put together plans for the world’s first powder rocket engine. Just days before his execution he passed his plans to the authorities, along with a note. The first paragraph read, 

“I, Nikolai Kibalchich, am writing down this design in prison with several days to go before my execution. I believed in the practicability of my idea and this belief sustains me in my appalling situation by scientists and specialists who show my idea to be practicable, I will feel happy in the knowledge that I have rendered an immense service to my country and mankind. I will then calmly meet death, knowing that my idea will not die with me but will remain with mankind for which I prepared to sacrifice my life.

On 3rd April 1881, Kilbalchich and his accomplices were led out of prison – each with two words written on their back – ‘a regicide’ – the killing of a king. Heavy nooses were placed over the necks of the condemned, and at 9.21 am, the stool Kilbalchich had been standing on, was kicked away. 

Sadly the papers with his design were consigned to the archives of the police department, but rumours of a groundbreaking design continued to swirl and even made it abroad. It wasn’t until 1917, that Nikolai Rynin re-discovered the design and it was published in the Byloye magazine in 1918. Kilbalchich’s groundbreaking idea was finally out. 

I know that was a substantial detour, so let’s get back on track.  

American author Robert A. Heinlein talked about powering spaceships with nuclear bombs in his 1940 short story “Blowups Happen”. But the first scientific proposal came in 1946 through Stanislaw Ulam and F. Reines working at Los Alamos. In fact, many who had worked on the Manhattan Project also went on to work on Project Orion. 

The project itself began in 1958 and was led by Ted Taylor at General Atomics, an American energy and defence corporation and physicist Freeman Dyson. If you’ve been with us since the early days of Megaprojects you might remember a video on a hypothetical solar gathering construction built around the sun called a Dyson Sphere, it was Freeman Dyson who first proposed such an idea in 1960 – while in the middle of Project Orion. He was obviously a busy man during this period, with a hell of a lot on his mind.  


The original plan for an Orion spacecraft was to detonate small nuclear devices behind the spacecraft and essentially ride the waves forward. I am well aware of just how absurd that sounds, but as I said, thinking outside the box. 

This was a time when nuclear energy was being touted as a potential saviour. Ford even began designs for the Ford Nucleon which was a car that would use a nuclear rod as fuel which could power it for 5,000 miles. At this point, the possibilities seemed endless. 

Each nuclear bomb would be ejected from the spacecraft and detonated moments later. The ship would be protected by a shock-absorbing “pusher plate”, weighing 500 to 1,000 tons, that would absorb the series of huge explosions and propel it forward at great speed. And when I say great speed, I mean that. There was an early belief that this could be the answer to interplanetary travel, and could have reached anywhere in the solar system in a year – while travelling to Alpha Centauri (our closest planetary system 4.37 light-years away) in a little more than a century. A voyager space probe would take roughly 77,000 years to get to the same location. 

It’s probably important to point out here that Orion would not be constantly hurling nuclear bombs for a hundred years, there’s no way a spacecraft could carry that many. Instead, it would accelerate rapidly for around 10 days until it reached its desired speed. At this point, the ship could coast for the remainder – but still at speeds that are unimaginable to us on Earth. 

Freeman described those working on Project Orion as ‘a bit mad’. This was a group who had been given the freedom to explore any idea that presented itself, no matter how bizarre or far-fetched it seemed, without the bureaucratic nonsense that often dogged projects like this. A system similar to the famed amateur rocket society, Verein fur Raumschiffahrt (VfR) which operated in Germany before World War II and included pioneers, Willy Ley, Hermann Oberth, Eugene Sänger, and Wernher Von Braun, was implemented. There was little to no division of labour, with scientists and engineers able to work freely together. If it had the sound of a mad-cap experiment, it kind of was, but those involved seemed to thrive under it.  


Eventually, designs for Project Orion came down to three options


This was thought to be the smallest practical design and would have had a diameter of between 17 and 20 metres (55ft – 65ft) and a weight of 300 tons. The small Orion would carry 540 nuclear bombs, each weighing 0.22 tons. 


The next step up had a diameter of 40 metres (131ft) and a total mass of 1,000-2,000 tons. This Orion would carry 1,080 nuclear bombs, weighing 0.37–0.75 t each. 


According to papers, this was known as an interstellar ark. A huge ship measuring 400 metres (1,312 ft) in diameter (roughly the same height as the Empire State Building) with a weight of 8,000,000 tons – equal to 9 Golden Gate Bridges. To propel this monster it would require 1080 atomic bombs, such as the midrange version, but each would weigh a colossal 3,000 tons.

Studies showed that through nuclear fission, Orion would be able to travel 9-11% the speed of light, that’s nearly 30,000 metres per second.  

In 1959 a true model emerged, 40 metres (131 ft) in diameter and as tall as a 20 story building. It would weigh 4,000 tons and designed to be able to return safely to earth. The crew module would be set over multiple decks and would include control rooms, crew quarters, eating areas – even a small shop. Whatsmore, the whole ship would rotate when it wasn’t accelerating which would provide artificial gravity on board.

As for the bombs, imagine a large-scale vending machine for atomic bombs. This was essentially what was being designed on Project Orion. Each of the bombs would need to be 15 cm (6 inches) wide and weigh about 140 kg (300 lb). Thousands of these bombs would be stored in the centre of the ship. During the ship’s acceleration period, they would be fed via a conveyor belt to a machine, not unlike a Gatling gun, and then fired out of the spacecraft at a rate of four per second. These bombs would then detonate 20 to 30 metres (65 to 100 ft) away and propel the ship forward at a thunderous rate. I don’t know about you but that all sounds strangely logical to me.  


Most of the problems that Project Orion faced could be put into two categories. Bureaucratic and scientific. While those on the project were able to work through many of the scientific issues, by the early 1960’s Orion was being viewed like a small child who many believed might grow up to be a psychopath. The horrors of Hiroshima and Nagasaki were still fresh in the mind, and the idea of using the number of atomic bombs Orion would need was unpalatable for many. 

The Defense Advanced Research Projects Agency (DARPA) was growing increasingly sceptical about the idea and it was eventually passed to the Air Force, who initially seemed receptive but grew tired of it once they discovered there would be next to no military value to the project. At the same time, Defense Secretary Robert Mcnamara stated that the funds for Orion would cease at the end of its current cycle. 

Project Orion was offered to potential backers, but even NASA who would have been a logical choice said no – mainly down to the use of nuclear weapons. Also, you have to think that Orion was in direct competition with traditional fuel rockets, and with NASA so deep in the   it is easy to see how they would shy away.   

One of the major engineering problems associated with Orion was the repeated blast on the pusher plate which could cause ablation (erosion), but an unexpected answer to this particular problem was found purely by chance. A test plate used had oily fingerprints left on it by accident, but after the test, those patches with the oil were the only area not to show ablation. But that wasn’t the end of the worries with the plate. Quite simply everything rested on this plate surviving on long journeys, and without full testing, nobody knew exactly how it would react. Would shards of metal fly off it at different angles? How would the bombs react in space? There was a multitude of questions that unfortunately could never be answered.  

Another major headache was how to get it into space safely. The rocket launch would be powered by a nuclear detonation which led to the obvious worry of nuclear fallout. These would be much “cleaner” atomic bombs than used in conventional warfare, but try telling that to anybody living near to this launch site. 


Between 1957 and 1965, 50 people worked on Project Orion which cost a total of $10.4 million ($85.5 today) a tiny fraction of the $25.4 billion ($154 billion today), spent on the Apollo program. 

The Partial Test Ban Treaty signed in 1963 by Britain, the US, and the USSR proved to be the final nail in the coffin and included banned tests above ground, in the air, or outer space. Those working on Orion fought for an exemption, but none was given. The world may have become a safer place, but one of the most outrageous concepts in recent history was effectively over. 

So what can we make of Project Orion nearly 60 years later? Was this utter madness that was allowed to carry on for years before somebody realised just how absurd it was? Or did we miss one of the most important scientific opportunities to further explore the universe?

In 1968, Freeman Dyson aired his views on the matter when he wrote, “This is the first time in modern history that a major expansion of human technology has been suppressed for political reasons.” His feelings were clear, but so was his determination that the idea should continue. His comments came with a new design. 

Dyson’s latest concept was for a spacecraft with a total mass of 400,000 metric tons, three-quarters of that weight would be 300,000 one-megaton H-bombs weighing 1,000 kilograms (2,205 pounds) each. The spacecraft would be 100 metres (330ft) in diameter, large enough to carry a colony to Alpha Centauri in 133 years. Ideas of how several generations of colonists would survive on board were sketchy, but he did include a plan where the pusher plate was made out of transuranic elements (atomic numbers greater than 92), which could be broken down and used for nuclear fuel upon arrival – wherever that arrival point might be.  


Make no mistake about it, Project Orion was stopped for political reasons rather than engineering or scientific. Just as the project was becoming an awkward hot potato for the U.S government, ideas were certainly forming into a coherent plan. 

But this was a project that was never really given a chance. Its paltry budget emphasised how important it was to the government and that fact that not a single live test with an atomic bomb was authorised meant it remained forever theoretical. While we might look back on it now as absolute lunacy, the fact that so many well-respected scientists, engineers and physicists felt so confident about it maybe tells a very different story. 

This was a project light years ahead of its time, and one we may well have to come back to in the future. We let our fears and lack of imagination get the better of us, but thank god some have the ingenuity and adventure to think in this brilliantly crazy way. 

But I will leave you with a final thought that has come to be associated with the theory around Project Orion. It is believed that one unmanned Orion carrying enough nuclear bombs could travel to and effectively deflect a 14 million ton asteroid a week before destroying our planet. If that failed, we would still have enough time to send another as a backup. For a truly monstrous asteroid, we could send a fleet of Orions to intercept this giant killer and prevent the destruction of our planet. Who knows, one day this crazy, forgotten and unloved project just might be our last hope. 

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  1. Could I get the sources for the stats on Super Orion? I’m doing a study on pulse propulsion and the 11% C velocity seems too heigh to be achieved with Orions escape velocity at fuel to mass ratios which make sense.


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