Something a little less London-centric today. So much has been written about the Manhattan Project, Los Alamos and the creation of ‘Fat Man’ and ‘Little Boy’ that you’d be forgiven for imagining there was little more to explore, but some extraordinary information was declassified by NASA telling the story of Project Orion.

America in the second half of the nineteen fifties was a nation obsessed with the atom. Science fiction dominated the drive-ins, cars came equipped with chromium rocket tail-fins and the semiology of atomic power, allied with Sputnik and the space race, infiltrated consumer consciousness in everything from fashion to flatware.

This public fascination with fission was a duel-edged sword; on one hand, the atom was a friend that would provide an unlimited power source for an energy-hungry planet, but it was also a symbol of a cold war that imposed a paranoid ‘duck and cover’ mentality on an entire generation of red-baiting blue-blooded Americans.

From this mindset came an idea so preposterous and fraught with danger that only a closed society like General Atomic, the project’s contractor, could have nurtured it. The idea was seemingly a simple one – to build an interplanetary 40,000-ton manned spaceship that would be propelled by detonating a series of nuclear bombs.


The theoretical physics behind it were appealing. Nuclear fission could be turned into a nuclear explosive and therefore a propellant. An upside-down version of the Orion theory had already been mapped out in 1955, whereby bombs could be detonated to create tritium in an asphalt-covered basin without greatly contaminating the air or surroundings. This scheme was known, appropriately enough, as BATS – Bomb Assisted Tritium Supply. The scientists’ main concern was a question of feasibility, not one of poisoning the atmosphere.

Propulsion by nuclear explosions was an imaginative concept that excited scientific researchers and led numbers of them to the same conclusions. Suddenly it seemed within the realm of possibility to send a large-payload vehicle off on ambitious voyages of space exploration.

‘We knew a lot about nuclear bombs,’ remembers Harris Meyer, a Los Alamos colleague. ‘If you threw a nuclear bomb out the back of a rocket ship, it exploded and gave it a kick.’ Nuclear rockets would, of course, prove disastrous if anything went wrong. The heat of decaying fission product could melt or vaporise its reactor in half a minute, and the fallout would be potentially lethal. Fallout was already a hot topic by 1954, when the Castle Bravo shot at Bikini yielded fifteen megatons instead of six, irradiating a boatful of Japanese fishermen, and Soviet tests had dumped fallout across Japan. Strontium 90 had a half-life of twenty eight years, and turned up in mother’s milk and children’s bones. Nuclear detonation was scaring everyone. ‘My mother liked Orion,’ says Ted, one of the Orion scientists, ‘but she didn’t like the bombs.’ To make matters worse, fission products released in the earth’s magnetosphere would slowly spiral along magnetic field lines back to earth.

So why would anyone persuade the government to invest millions in such a madcap project? This could partly be explained by the potent nationalism of the Eisenhower years, but owed more to the awestruck enthusiasm of the scientists behind the project. Freddy de Hoffman calculated the ballistic trajectories for ‘Fat Man’ and ‘Little Boy’, and was granted $10 million to start up General Atomic. Napoleonic by nature, his dreams were driven by a grandiosity that manifested itself in the creation of a Google-like Xanadu for his young (as young as nineteen years old) scientists. These were physicists ‘closer to God than anyone else’, and needed to be nurtured by the right environment.

The rocket itself was envisioned as a Melies-style bullet, with a broad round base, a snub nose, and a plunger to create timed explosions. The proposed 200-ton test rocket developed in 1962 was 30 feet in diameter, but the yield of its charges was still unknown. According to the research, propulsion was possible, but just how much would it take to power a rocket to its destination and back?


Throughout Orion’s development there seems to have been an extraordinarily cavalier attitude to its potential lethality, but there was a sense that harnessing the atom was just the start of a brave new world of fission-power. This was not long after plutonium had been transported to Los Alamos in the back of an Oldsmobile. The launch of the Nautilus in 1955 led the way to a fleet of nuclear submarines, nuclear-powered aircraft and surface-ships, and nuclear-powered space vehicles were simply the next logical step.

General Atomic, now a mini-Pentagon, needed to build a research reactor that would be ‘safe even in the hands of an idiot’. Niels Bohr was brought in for the ignition ceremony and proved enthusiastic about the spaceship. The first ‘boost’ test, in effect a small fusion spark plug, created a fireball five times the size of Hiroshima and cracked the martini glasses at the scientists’ beach house bar. The plan (a modern global nightmare) was to create nuclear bombs so small you could hold them in your hand. The heat generated by each detonation would touch the base-plate of the rocket plunger for such an infinitesimal time period that no damage would be done to the rocket.

A plan evolved to fire the rocket to Mars, but there were flies in the ointment; Eisenhower’s moratorium on nuclear tests, the question of a military presence in space, the idea of manning each ship with forty people – and eventual disavowel by NASA. Even the supportive Werner Von Braun had his spirit knocked out by government bureaucracy. The project broke all the rules of the political game, and General Atomic’s costings had been wildly optimistic.

George Dyson’s book ‘Project Orion’ is a lucid, anecdotal dissection of the project, which is unthinkable in today’s climate; it skirts hard science but never quite loses you in technical detail. Orion fired the imagination of an isolated scientific community, and a single idea almost came to fruition on the sheer willpower of its proponents.

This forgotten episode in the space race now seems, to a layman like me at least, like a nightmare of recklessness. Yet to this day, scientists believe that Orion’s time will come and nuclear pulse propulsion will return.

3 comments on “Atomic!”

  1. brooke says:

    Outlier here. You’re captured the mood in the US very well in your second paragraph. And in my peregrinations of early years I bumped into some of the Manhattan Project scientists who went on to Orion and then retreated into universities. Later their reputations were overhauled by a younger generation that was delving into the history of the Manhattan project. There’s a story to be told of lives lost–ordinary people.
    It’s my understanding that the science has advanced beyond the nuclear pulse theory but since there is a strong push to Mars, who knows what will happen. (I think von Braun is Wernher).

  2. Roger says:

    Freeman Dyson, George’s father, discusses the project in one of his books and I think Richard Feynman was involved.
    As well as nuclear-powered ships, there were also plans for nuclear-powered aeroplanes.

  3. Mark Pontin says:

    Curtis LeMay at SAC wanted a nuclear-powered bomber that could stay in the air for six-nine months and the reactor developed for that, the molten salt reactor, was and is the concept that we know today as the thorium reactor.

    In the early 1970s, NASA developed another concept, the Nuclear Engine for Rocket Vehicle Application (NERVA), for the proposed Mars mission that would have followed Apollo had Nixon not cut the funding, NERVA was all proved out and ready to go, and I believe NASA may be reviving the concept for a proposed Mars mission somewhere in the 2030s. Certainly, chemical rockets make no sense beyond the Moon.

    This is as distinct from the original Orion concept that Dyson and Ted Thomas spearheaded for General Atomic, which was the most grandiose of all as our illustrious host notes. The original Orion concept is also known as a nuclear pulse drive and you can some idea of what a sophisticated version of that would be like from Stanley Kubrick’s and Arthur C. Clarke’s 2001, because that’s what powers the spaceship that takes Bowmand and the others to Jupiter.

Comments are closed.

Posted In