May 30, 2020

Declassified: The True Tale of Project Orion.

Artist’s conception of an Orion vessel about to depart from Mars orbit. (Credit: NASA).

Ever wondered if man will ever head to the stars? Certainly, the magnitude of the issues that need solving for interstellar travel are many times more difficult than a simple spin around the block in our solar neighborhood… radiation exposure, sustainability of resources, and the effects of time dilation would all come into play. And yes, in these troubled times, we’re finding it exponentially difficult to even leave low Earth orbit… but did you know that the U.S. government once seriously researched the feasibility of interstellar transportation using current technology? Let me tell ya’ a story….

It all started with a proposal made by Stanislaw Ulam and Fredrick Reines in 1947 for an atomic pulse engine. The idea was primitive but effective; a large city-sized spacecraft would be propelled by shooting atomic bombs aft and gaining continuous momentum as the blasts pushed the gigantic craft forward. The idea gained steam around 1958 and the dawn of the Space Age (remember, it was the birth of NASA and the time of Sputnik) and interest was sufficient that Princeton’s own Freedman Dyson (he of the Dyson sphere) took about a year to draft a proposal on the project. Even today, it’s a fascinating read; it shows just how ambitious some of those early ideas really were, and all in an era prior to even sub-orbital space flight! Dubbed Project Orion, (Not to be confused with the Orion capsule of the modern day Constellation Program) the system would provide both high thrust and high specific impulse and would have been one heck of a ride. Scaled plans would have ranged from an interplanetary “Orion-lite,” a 4,000 ton spacecraft equipped with 800 0.14 kiloton bombs, to massive interstellar versions capable of accelerating at 1 G for a sustained period of 10 days up to about a cruise velocity of about 3.3% the speed of light. Of course, such ships would be generational, as even a one way trip to Alpha Centauri would take about 100 years. And you would need to decelerate on the other end… and you’d have to take all of your nuclear fuel with you for all of this. Probably one of the biggest issues would be designing large shock absorbers to sustain repeated blows against the pusher plate; few spares could be towed along, and if they were damaged, there would be little hope of replacements. Then there’s the threat of high energy particles zipping right though the craft and your DNA at relativistic speeds… there are certainly many problems to solve with long term interstellar travel.


Still, some tentative earthbound tests were in fact done to see if a pusher plate could survive an atomic explosion. One of the early tests involved the suspension of two graphite encased steel spheres near an explosion during the 1954 Operation Castle nuclear test series in the South Pacific. The spheres were recovered intact, suggesting that it was possible to construct materials capable of surviving a nuclear blast. One of the more bizarre tales of the Cold War involves Operation Plumbbob. Amidst trials involving pigs and troops exposed to atomic testing was a test on August 27, 1957 entitled Pascal B in which a 900 kg capping plate was set to be expelled by the blast at a calculated 6 times escape velocity. The plate was never found and only appears in the first few frames shot by high speed camera; the plate either A. vaporized entirely, or B. Is now a reluctant orbiting citizen of our solar system! Such are the tales of the Cold War…


Schematics from the original Dyson Report for an intermediate sized Orion spacecraft. (Credit: NASA).

So, would Orion be worth doing today? The Partial Test Ban Treaty of 1963 put the kibosh on the project, as it curtailed nuclear testing in space. Certainly, for interplanetary exploration, it still has its merits. Carl Sagan notes in his outstanding Cosmos series that “space exploration is the best use of nuclear weapons that I can think of…” A craft like Orion would have to be constructed in space preferably at one of the solar or lunar LaGrange points, i.e. accessible but sufficiently distant that the resulting electro-magnetic pulse of acceleration wouldn’t be a factor. A common objection heard is the seeding of radioactive contamination of space, but I would contend that space already has an abundance of radiation to begin with. Perhaps a bigger problem would be the potential of stray misfired or dud nuclear bombs orbiting the solar system… (Perhaps a lunar farside or space-based laser ready to remote detonate them would be in order?)  Interestingly, Coca-Cola once consulted on the design of the dispenser! Think a ramped up soda machine, dispensing nukes instead of Cokes… You’d definitely want a way to “jettison the core” in the event of a jam!

Orion-style spacecraft also occasionally popup in modern day science fiction; the Sci-Fi series Virtuality depicts an Orion vessel, and Larry Niven evokes an Orion designed spacecraft to fend off an alien invasion in the novel Footfall… you never know when a nuke dispensing spacecraft will come in handy…

If nothing else, Project Orion is a fascinating thought exercise that shows we could do interstellar travel now as a species, if we really wanted to. And unlike fusion or Bussard Ram-scoop proposals, Orion involves propulsion technology that is present today. If we’re to get out into the solar system, nuclear technology is the best option to do it. Will us Earth-based amateurs one day watch the brilliant explosions visually similar to Iridium flares of Orion spacecraft departing on brave new voyages? One can only dream…



  1. Jason says:

    I think nasa still has a small department for this system today. Because it is the fastest method of propulsion that our current technology can produce. The thinking is that it would be an off the shelf technology that would be used only in a emergancy situation to stop an incoming asteroid or comet. I’m guessing the new nasa orion capsule, being modular, would be capable of being connected with this system should such a need arise (in case we get unlucky with that asteroid Aphosus or I think that how it’s name is spelt).


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