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Launching a rocket using atomic explosions?

Glenn Reynolds and Leigh Outten have just co-written a short paper advocating the use of “pulsed nuclear space propulsion” to launch rockets. You can download it here.

The concept, as first described in the 1950s, is described in the paper as follows:

It is not a tremendous surprise that when you set off an atomic bomb next to something, that something will move. That it could also remain essentially intact, however, was considerably more surprising. The challenge for the Orion team was to produce a spacecraft that could function after being subjected to not one, but many, nearby nuclear detonations, and that could be steered and navigated by an onboard crew.

This turned out to be easier than it sounds. The Orion spacecraft design that resulted involved a large steel “pusher” plate, behind a rather large spacecraft with a total weight of over 4,000 tons. That sort of design is very different from the spaceships we’re used to today.

The bulk of their paper reviews the legal obstacles to launching such rockets, as both the Outer Space Treaty and the Limited Test Ban Treaty put limits on the use of nuclear weapons in space. The paper argues that these limits would not apply to rockets propelled by atomic explosions, since the explosions would not be used as weapons.

The paper also argues that the technical obstacles for building such rockets are also solvable, and might even be easy to solve. This particular quote stood out starkly to me:

In fact, one of the greatest appeals of Orion was that over a wide range, the bigger you made it, the better it worked. While chemical rockets scale badly – with big ones much harder to build than small ones – Orion was just the opposite. That meant that large spacecraft, capable of long missions, were not merely possible, but in many ways actually easier, for a variety of reasons, than small ones. Bigger spaceships meant more mass for absorbing radiation and shock, more room to store fuel, a smaller proportion of total size needed for radiation shielding, and so on.

Sounds great, doesn’t it? Color me skeptical. While I firmly believe we should never dismiss lightly the dreams of engineers, and that by giving them the chance to do impossible things impossible things are sometimes achieved, I also always take with a very very large grain of salt statements of over-confidence like the one above. Designing a giant rocket like this that will be powered by repeated nuclear explosions will not be easy. And though scaling it up might increase its launch efficiency it will not ease the design process. Just figuring out how to handle the large components will be incredibly challenging.

However, even if technically a rocket launched using repeated atomic explosions was doable, I have grave doubts it will ever happen on Earth. I’ve read these arguments in favor of nuclear pulse propulsion over and over again for decades, and remain completely unconvinced it can overcome the political opposition to it. The irrational and rational concerns about using repeated atomic blasts to lift a rocket off the ground will kill any effort to fund this work, or allow private companies to do it.

Assembling such a rocket in space for interplanetary travel, however, is more possible, and in fact will likely be accomplished by the future space settlers living on the colonies nations build on the Moon, Mars, and asteroids. It will however also require a robust self-sufficient civilization in space, something that is probably at least one to three centuries away.

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On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.

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  • David Eastman

    Apparently rather substantial amounts of Uranium ore have been observed on the Martian surface. The Moon also has Uranium traces in the lunar dust. Mercury and Venus should also have large amounts of Uranium, as well as the asteroids. I imagine that in the hopeful future where exo-Earth culture becomes a thing, “environmentalism” is going to translate to “stop doing anything nasty on Earth, keep the habitats clean, but outside where we’re trying to build a new industrial age, piss off.”

  • Col Beausabre

    I know where we can launch it from – Red Square

  • Jeff Wright

    I can get behind nuke-pulse propulsion. Speaking of Russia-I hear their troops lack optics and some issued bolt action Nagants! Wha…? They ship all their AKs to Angola?

  • Alton

    Well according to some Intel reports China has on the order of 500 million AK-47 variants in storage for the day of need. …
    Chech and East Germany were large producers of arms for the Soviet war Machine, now on the wrong side.
    Also according to the state of storage of old Soviet era gear reported, most of it is rusted welded masses of junk.

  • James Stephens

    Atomic Rocket to Mars! How 1950s grade B Sci-Fi. God I love it! No doubt launched from some volcanic island near Japan.

  • pzatchok

    My thought is that all the energy that goes out to the sides and bottom would be lost energy that could be used for forward thrust.

    My argument is basically a flat plate vs a thrust chamber.

  • Heavy-metals rich asteroids like 16 Psyche (the surviving core of a differentiated protoplanet such as Vesta) are the obvious place to look for fissionable elements like uranium.

  • pzatchok

    As for bolt action Nagants.

    I bought one and a span can of ammo for 100 bucks back in the day. I sold it as soon as the ammo ran out,
    It shot fine and was as accurate as the Russian ammo but not what I wanted for the long run.

    I have friends with a dozen and almost no ammo. No ammo equals no gun to me.

    The Russians got rid of all their Nagants years ago.

  • This paper doesn’t mention the really big problem with Orion, which is nuclear weapons proliferation.

    For Orion to work, you need to manufacture thousands and thousands of small nuclear devices. These could easily be converted for use as a weapon, if they fell into The Wrong Hands. And for sure some would.

    So you’ve got an enormous security issue. That’s what finally soured Ted Taylor on the idea. He knew it was relatively easy to build a bomb, once you acquire sufficient nuclear material.

    I was fortunate to discuss Orion with both Ted Taylor and Freeman Dyson. Brilliant men, both of them.

  • sippin_bourbon

    For a surface launch, it seems like a bad idea, but up in space, why not?
    I would think it would be incredibly bumpy.

    Do they address potential EMP effects?

  • John

    If we want to move about the universe, I think nuclear power is the only semi-practical way to do it. I think we’ll have to wait until fusion reactors power something like a massively scaled up ion thruster.

    It would be cool to see a prototype Orion since it can be done with today’s technology. Nuclear proliferation is a non-issue, second and third world countries can refine the materials now. Sorry to say.

  • sippin_bourbon noted: “I would think it would be incredibly bumpy.”

    The designs I’ve seen use a shock-absorbing plate to smooth the ride. I’ll leave the details to your imagination, because the designers did.

    There is better tech on a shorter time horizon than approval of a multi-nuke launcher. Interesting, and can be simmed, but not likely.

  • James Street

    “it could move through space at about a hundred thousand miles an hour, top speed”

    If it was 10% the speed of light I’d really be interested in this. Hello Alpha Centauri.

    I thought it was the nuclear bomb method but it must be the small, light craft with a large solar sail pushed by a ground based laser that claimed it could approach 10% the speed of light.

  • wayne

    Can’t readily locate a video link for Project Orion, but here’s a brief text backgrounder
    ((I always have this sneaking suspicion we (re)pay for research over-n-over again.))

    NASA Technical Reports
    “Nuclear Pulse Propulsion: Orion and Beyond”

    “This paper discusses the rationale for nuclear pulse propulsion and presents a general history of the concept. focusing particularly on Project Orion. It describes some of the reexaminations being done in this area and discusses some of the new ideas that could mitigate many of the political and environmental issues associated with the concept

  • wayne

    To Mars By A Bomb –
    The Secret History of Project Orion

  • wayne

    I sense some skepticism on your part. (tone is so difficult to decipher in text!)

    This, on the other hand, looks perfectly feasible!

    Nuclear Propulsion in Space (1968)
    “NERVA” “nuclear engine for rocket vehicle applications”

  • Steve Richter

    “… If we want to move about the universe, I think nuclear power is the only semi-practical way to do it. I think we’ll have to wait until fusion reactors power something like a massively scaled up ion thruster. …”

    how does a nuclear powered space craft get rid of the heat from an on board nuclear reaction?

  • Gealon

    Steve Richter, Large radiator panels. You can occasionally see it in more realistic scifi. In Fact, Discovery 1 from 2001 was supposed to have radiator panels all down it’s spine, but that was nixed out of fear that the audience would think they were wings. I say, never underestimate the audience’s intelligence, especially if they are going to see a movie like that.

  • Daniel Kaczynski

    In case you haven’t seen it, let me recommend Scott Manley’s YouTube channel and
    his video on the nuclear salt water rocket. Whoever came up with that idea certainly
    had an overactive imagination and probably spent his high school years tinkering with
    homemade pyrotechnics { as, I suspect, some of you did! ;) } but it does sound plausible.

  • Questioner

    Attack drones “Inokhodets” struck at fortifications and armored vehicles of the Armed Forces of Ukraine

  • Questioner

    The pilot of the Su-25 attack aircraft managed to land the plane after a MANPADS missile hit it

  • Col Beausabre

    NERVA and Orion were hardly “secret” projects. That they are not widely known is that there were shut down. You `can even tour the nuclear engine test site.

  • Isaac Arthur did an episode on that, a while back.

    Launching from Earth is never going to happen, but I agree that there is no reason not to use them elsewhere.

  • sippin_bourbon

    So I skimmed the paper.
    I did not see any reference to EMP effects.
    And I have never seen in mentioned in Project Orion.
    I do seem to remember a reference to “Shock Absorption”

    But being that close to a small nuke going off it going to have an EMP effect.

    I know that a lot of electronics used in space are considered “hardened”, but it still seems risky, shorting out the entire vessels electronics at the start of a voyage.

  • Mike Borgelt

    Nuclear proliferation is used as an argument against fission power reactors too. Silly argument, as any government which wants nuclear weapons will get them anyway.
    EMP effects can be shielded and hardened against if indeed there is a problem as the ship is in the shadow of a large thick steel plate. The charges are only around 10 tonnes TNT yield.
    Wernher von Braun took a look at the Orion team’s chemical powered small scale demonstration and was instantly converted. Impressive, as he’d spent his life on large chemically powered rockets.
    It comes down to “do you want a large scale human presence in the Solar System or not?”
    I still hold out hope for a working demonstarion of unconventional fusion which can run on B11 – proton reactions. Minimal neutrons and direct conversion to DC power as the reaction produces 3 alpha particles.

  • Chris

    Wayne you beat me again. I was going to look up the NERVA after reading this article this morning.

    I took a graduate control class at U of Pittsburgh long ago. Ken Cooper was the the professor. He worked on the NERVA. I remember him commenting on “reducing that data was so cool” as any PhD would.

    As a trivia note Dr Cooper could write so fast on the chalk board (and I so slow in my notes I guess) that I had to hit my pentel pencil off my forehead, advancing the lead, to try and keep up.

  • ghbucky

    What we really need to know: will KSP2 have them?

  • Annoying Old Guy

    There is this old video of an Orion prototype using chemical explosives.

  • Calvin Dodge

    “What we really need to know: will KSP2 have them?”

    The promo video for it showed an Orion ship.

  • Jeremy

    The book “Project Orion” by George Dyson is one of the best science/engineering books I’ve ever read. George is the son of Freeman, an important figure in physics and who worked on Orion. It is one of the very few items that has an Amazon review by Jeff Bezos. The book can sell for silly prices, but I found mine on Abe Books for a reasonable number.

  • Wayne and COL. Beausabre:

    I was a fan of NERVA as a kid, and disappointed that it didn’t go anywhere, I have some documentaries with footage of the reactor interior at full thrust. It’s pretty cool. There is a NERVA display at the Atomic Testing Museum in Las Vegas.

  • Robert

    “My thought is that all the energy that goes out to the sides and bottom would be lost energy that could be used for forward thrust.”

    The designers actually addressed that issue. By creating what could more or less be considered a nuclear shaped charge. I forget the actual numbers, but it was something like 80% of the energy could be focused on a cone 30 degrees wide, focusing more of the blast on the pusher plate.

    Of course, they then started work on making that cone narrower… which quickly dropped the efficiency but extended the range. Making a potentially interesting weapon system, at least for use in space. Look up Casaba Howitzer for details.

  • Nuclear EMP only occurs when the explosion is in (or really near) the atmosphere. So out in space it’s not an issue. That’s probably why this paper didn’t discuss EMP.

    And, proliferation of nuclear weapons is truly a serious issue — but mostly for non-state actors. It’s a political problem, not a technical problem. But you can’t just hand wave it away.

  • wayne

    Operation Fishbowl (1962)
    High Altitude Weapons Effects

  • wayne

    Operation Fishbowl (1962)
    High Altitude Weapons Effects

  • sippin_bourbon

    I was not sure if an atmosphere or magnetosphere was required for EMP or not.
    I have no background in that area.

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