[HN Gopher] Project Orion
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       Project Orion
        
       Author : tosh
       Score  : 66 points
       Date   : 2023-03-16 18:09 UTC (4 hours ago)
        
 (HTM) web link (en.wikipedia.org)
 (TXT) w3m dump (en.wikipedia.org)
        
       | aftbit wrote:
       | See also Anathem by Neal Stephenson
        
       | dang wrote:
       | Related:
       | 
       |  _Orion Project [pdf]_ -
       | https://news.ycombinator.com/item?id=22691219 - March 2020 (1
       | comment)
       | 
       |  _Project Orion (nuclear propulsion)_ -
       | https://news.ycombinator.com/item?id=9025611 - Feb 2015 (11
       | comments)
       | 
       |  _Project Orion (nuclear propulsion)_ -
       | https://news.ycombinator.com/item?id=3019627 - Sept 2011 (1
       | comment)
       | 
       |  _Project Orion is one of the stupidest, most wonderful ideas
       | ever conceived in America._ -
       | https://news.ycombinator.com/item?id=261348 - July 2008 (6
       | comments)
       | 
       | That's less than I expected - are there other threads?
        
         | antondd wrote:
         | _Interstellar nuclear-powered transport (1968)_ -
         | https://news.ycombinator.com/item?id=28132756 - Aug 2021 (34
         | comments)
         | 
         | There are a few more, under different titles. I remember
         | reading Dyson's autobiography a couple of years ago and he
         | mentioned his involvement in the research. Absolutely amazing
         | stuff.
        
           | didericis wrote:
           | There's a great BBC documentary on this called "To Mars by a
           | Bomb", highly recommend it. Was one of my first introductions
           | to Freeman Dyson, ended up reading his autobiography as well.
           | Was a remarkable man, and one of my favorite people to listen
           | to.
        
             | smilespray wrote:
             | It's on YouTube, and I second this recommendation.
             | 
             | https://youtu.be/xYoLcJuBtOw
        
           | hermitcrab wrote:
           | I watched all 157 of these: https://www.youtube.com/playlist?
           | list=PLVV0r6CmEsFzDA6mtmKQE... Really interesting.
           | 
           | I spoke to him once at a book signing and asked him about
           | Orion. In summary he said: would it have worked - probably,
           | should it be done - probably not. Although he did make the
           | point that pretty much every big engineering project kills
           | people.
        
       | marktangotango wrote:
       | There was a classic science fiction story with a twist on this
       | idea; a low tech species was about to be discovered by a more
       | advanced species. And according to the rules of the more advanced
       | species, any planet that wasn't capable of space travel would
       | become a client or vassal, and a planet with space travel would
       | be seen as a peer. The protagonist built a pusher style rocket
       | using an explosive, and launched the lightest person he knew into
       | orbit, who happened to be his girl friend.
       | 
       | I keep thinking this was a Larry Niven story, maybe someone here
       | is familiar?
       | 
       | Edit; another classic story was the novel Footfall by Niven and
       | Pournelle which featured launching the USS Missouri into orbit on
       | an Orion style pusher to battle the invading aliens.
        
         | Arrath wrote:
         | I very much have a soft spot for Footfall. Sending up a
         | battleship kludged into an Orion style ship to battle alien
         | invaders is just so cool.
        
           | variaga wrote:
           | I haven't read that book in 30 years, but the description of
           | experiencing the launch from inside the craft was so succinct
           | and evocative I still think about it from time to time.
           | 
           | "God was knocking and he wanted in _bad_. "
        
             | vhodges wrote:
             | One of my favourite lines ever! Note, it wasn't from the
             | perspective of inside the craft but rather the towns people
             | huddled in a bunker in Bellingham.
        
         | mpweiher wrote:
         | > Footfall by Niven and Pournelle which featured launching the
         | USS Missouri into orbit on an Orion style pusher
         | 
         | Yes, there was an Orion. No they didn't launch the USS
         | Missouri. The ship was called Michael and featured, among other
         | crazy weaponry, X-Ray lasers of the SDI type, i.e. some
         | material (ruby?) pumped by a nuke. The nuke would destroy the
         | material, but in the process get it to lase X-Rays. Heck, if
         | you're using nukes for propulsion, might as well do that as
         | well.
         | 
         | Maybe they repurposed the guns for something?
         | 
         | I distinctly remember some dialogue that there was some fairly
         | rough welding of thick steel plates going on, none of the
         | ultra-fine tolerances of traditional rocket engineering.
        
         | vhodges wrote:
         | replying to all... The story you're thinking of is King Davids
         | Spaceship by Jerry Pournelle. It IS a co-dominion story (so
         | same universe as The Mote in Gods Eye w/Larry Niven)
         | 
         | A few other uses of Orion in fiction that I am aware of:
         | 
         | The Ship 'Michael' (as in avenging angel) from Footfall (Again
         | by Niven and Pournelle).
         | 
         | And the ship from Orion shall rise by Paul Anderson.
         | 
         | A CBC Miniseries featuring a (faked) Orion derived interstellar
         | ark supposedly launched in the 60's and the people that have
         | been living on it for almost 40 years.
        
         | AnimalMuppet wrote:
         | "King David's Spaceship". I believe it was by Niven, but I'm
         | not sure.
        
           | nyrath wrote:
           | "King David's Spaceship" aka "A Spaceship For The King" by
           | Jerry Pournelle
        
         | KineticLensman wrote:
         | That doesn't sound part of Niven's Known Space canon.
         | 
         | However, 'Footfall' by Niven and Pournelle does have an Orion,
         | as does Invisible Sun, by Charles Stross.
         | 
         | Nothing obvious in [0]
         | 
         | [0]
         | https://en.wikipedia.org/wiki/List_of_stories_featuring_nucl...
        
       | ianburrell wrote:
       | Project Orion is a really bad idea. I guess it could be a good
       | idea in specific situation where have to get a lot of mass off
       | the planet and don't care about the effects.
       | 
       | Problem one is that detonating a series of nuclear bombs in the
       | atmosphere. The first couple are close to the ground and produce
       | local fallout, the higher ones produce global fallout.
       | 
       | Problem two is that detonating nuclear bombs in space causes EMP.
       | That doesn't destroy electronics on ground as thought but will
       | knock out the electrical grid. The extra radiation will knock out
       | satellites in space.
       | 
       | There is interstellar Orion, Project Daedalus, but that is quite
       | different with inertial confinement fusion and magnetic fields
       | directing the exhaust.
        
         | tomatotomato37 wrote:
         | Not as "spicy" an idea as the Nuclear saltwater rocket however,
         | which instead of discrete bombs involves dissolving a load of
         | bomb-grade fissiles into water and then ejecting them out a
         | conventional rocket engine, with the idea the solution goes
         | critical somewhere in the vincinity of the exhaust nozzle. Now
         | if you're thinking "Does that replace singular discrete nuclear
         | explosions with a continual nuclear explosion shrouded in an
         | expanding cloud of radioactive superheated steam?", the answer
         | is yes, yes it does.
         | 
         | Weirdest thing is the design doesn't actually have as much
         | potential ISP as a pulsed detonation system like an Orion,
         | despite being a bonafide torchship. Go figure
         | 
         | https://en.m.wikipedia.org/wiki/Nuclear_salt-water_rocket
        
         | nwah1 wrote:
         | Launching from lunar orbit would obviate EMP and terrestrial
         | radiation concerns.
         | 
         | But those are the least of the concerns.
        
           | ianburrell wrote:
           | The problem with that is Orion is that it is heavy. It only
           | makes sense when launching the whole thing from the ground.
           | Orion has been proposed for interplanetary propulsion since
           | it is pretty efficient. But would need to be convertible from
           | ground-launch to space propulsion. Nuclear rockets are pretty
           | good and safer to launch.
           | 
           | The other problem is that nuclear weapons are expensive.
           | Something like Davy Crockett is 2kg of plutonium, and mid-
           | sized Orion would use 800 to get to orbit. Plutonium is
           | $4000/g which means $6.4 billion to launch Orion. Orion that
           | puts 1600t in orbit. Or 10 Starships which is less as
           | disposable rockets and way less if reuasable.
        
             | philipkglass wrote:
             | In 1965 the Atomic Energy Commission put the cost of
             | plutonium 239 at $10/gram, which by simple consumer price
             | indexing (only a rough guide, admittedly) would make it
             | $96/gram today.
             | 
             | See Table I in this publication "Values In Spent Fuel From
             | Power Reactors":
             | 
             | https://www.osti.gov/servlets/purl/4618921
             | 
             | At $96 per gram instead of $4000, that's a much more
             | attractive $154 million to put 1600 tons in orbit. Uranium
             | enrichment costs have fallen greatly since the 1960s as
             | centrifuges have replaced gaseous diffusion, so uranium-
             | fueled units would probably cost less (despite the greater
             | mass of uranium required).
             | 
             | I'd say that the main modern problems of a terrestrially
             | launched Orion are treaty violations and giving a plausible
             | cover for nations to again pursue developing "peaceful"
             | nuclear explosives.
        
         | hermitcrab wrote:
         | IIRC the estimate was that the extra radiation from a launch
         | would kills tens of people per launch, not thousands. Still not
         | great (especially if you are one of those victims), but not as
         | much as you might expect.
        
       | tppiotrowski wrote:
       | There is also a book called Project Orion: The True Story of the
       | Atomic Spaceship. It's still sitting on my shelf, but I don't
       | remember it being a particularly inspiring read because it was
       | tailored towards interstellar travel when we hadn't even reached
       | Mars yet.
        
       | rqtwteye wrote:
       | Makes me wonder if there ever will be a type of propulsion that
       | doesn't rely on throwing out mass behind a spaceship.
        
         | toast0 wrote:
         | https://en.wikipedia.org/wiki/Solar_sail doesn't throw mass out
         | the back. Although, it's not a lot of propulsion, it's
         | something.
        
       | simonebrunozzi wrote:
       | Title should better be "Project Orion (nuclear propulsion)".
       | 
       | There's too many "Orion" things out there to make it clear that
       | this specific one is about nuclear propulsion.
        
       | breppp wrote:
       | Similarly crazy idea, https://en.wikipedia.org/wiki/Nike_Hercules
       | A nuclear tipped SAM, blow all the missiles out of the sky
       | together with the sky
        
         | HPsquared wrote:
         | Related, Sprint missile test (anti-ballistic-missile missile).
         | Extremely fast acceleration, you can see in the test footage
         | which is not sped up.
         | 
         | Mass: 7,700 lbs.; Thrust: 650,000 lbs.
         | 
         | Around 100 G of acceleration, reaching Mach 10 within 5
         | seconds.
         | 
         | "The first stage was exhausted after only 1.2 seconds, but
         | produced 650,000 pounds-force (2,891 kilonewtons) of thrust. On
         | separation, the spent first stage disintegrated due to
         | aerodynamic forces. The second stage fired within 1 to 2
         | seconds of launch. Interception at an altitude of 1 to 19 miles
         | (1.5 to 30 km) took at most 15 seconds."
         | https://en.m.wikipedia.org/wiki/Sprint_(missile)
         | 
         | https://youtu.be/kvZGaMt7UgQ
        
           | [deleted]
        
         | roywiggins wrote:
         | The Russians still have theirs.
         | 
         | https://en.wikipedia.org/wiki/A-135_anti-ballistic_missile_s...
        
         | moffkalast wrote:
         | And well, the Genie missile of course
         | https://en.wikipedia.org/wiki/AIR-2_Genie
        
         | ianburrell wrote:
         | Nuclear tipped SAM isn't too crazy for the time. They were
         | defending against nuclear-armed supersonic bombers and knocking
         | out multiple with one missile was good idea. Early SAMs also
         | weren't that good.
         | 
         | There were lots of nuclear tactical weapons (some bonkers) at
         | the time. Nuclear torpedos. Nuclear anti-submarine rockets.
         | Nuclear artillery shells. Nuclear tactical rockets.
        
       | LesZedCB wrote:
       | it was a fun plot point of the Remembrance of Earth's Past
       | trilogy (Three Body Problem) too
        
       | ShakataGaNai wrote:
       | There is a Kerbal Space Program mod [1] that adds this to the
       | game. It is hysterically fun to use because it is insanely
       | unbalanced compared to normal space flight requirements. Want to
       | change your orbit 180deg and fly backwards? No problem. Goto any
       | planet the "direct" route? Sure, why not. Take off from the
       | launch pad so fast you'll think the game broke? Not a problem -
       | The Kerbal's don't worry about a little fallout.
       | 
       | No idea how this would ever actually work in reality for manned
       | spaceflight. For unmanned it seems relatively doable (ignoring
       | the entire cost of getting it off the ground and into space
       | first). But for a manned mission? Being subject to 2-4g is one
       | thing, but to have it happen regularly... like a jackhammer
       | almost? Sounds like a _really_ bad trip. You could not do
       | anything while that engine was firing (not that it 'd be easy to
       | do something under 2g constant acceleration) without risk of
       | being in the wrong place/position at the wrong time. I don't know
       | what the long terms effects of repeated, assumingly rapid, 2-4g
       | pulsing is on the human body.... but I'd guess it falls under
       | "can't be anything good" category.
       | 
       | [1] https://umbraspaceindustries.github.io/UmbraSpaceIndustries/
        
         | galacticaactual wrote:
         | So there are ways to make this interesting in the game and
         | bring it back to balance. Some recommendations:
         | 
         | - The USI pulse nukes are expensive. Play on career mode so you
         | are cash constrained and have to rigorously plan for their
         | build, use, and refueling.
         | 
         | - Roleplay not using them anywhere near low home-planet orbit
         | for fallout reasons. I.e. the ship is built and is parked in a
         | shipyard in Cislunar space and kerbonauts must ride an
         | intermediary shuttle vessel to crew it.
         | 
         | - Use a life support pack and planet mods that add
         | interplanetary destinations. Having your kerbonauts on a nuke
         | ship around an extrasolar planetary body far away from home
         | with limited supplies will add plenty to the mix.
        
         | whatshisface wrote:
         | Based on the amount of time a Kerbal can survive orbiting the
         | sun in their barely-shielded capsules, I am inclined to think
         | that they are immune to radiation damage, like tardigrades.
        
         | adrenvi wrote:
         | Project Orion uses a pusher plate mounted on giant springs to
         | spread out the force of each explosion. If the system is
         | designed correctly it should result in constant acceleration.
        
         | BitwiseFool wrote:
         | This was supposed to be in Kerbal Space Program 2, and you can
         | see an early version of it in some of the promotional
         | materials. Time will tell when it makes its way into the game.
        
       | st_goliath wrote:
       | An other quite interesting concept (also a little less "out
       | there" and actually, successfully tested) is the NERVA engine,
       | also linked at the bottom of the article[1].
       | 
       | It uses a nuclear reactor to heat up a single propellant (liquid
       | hydrogen) which then rapidly expands as it goes out the nozzle at
       | the end, resulting in quite high specific impulse and is more
       | efficient than a chemical rocket.
       | 
       | If we want to go really _far out_ in terms of crazy rocket
       | designs, there is also the concept of the nuclear salt-water
       | rocket[2][3].
       | 
       | This one uses enriched plutonium or uranium salts, dissolved in
       | water, inside a neutron-absorbent fuel tank design. The water is
       | pushed out through a pipe, where an uncontrolled chain reaction
       | starts. If it goes fast enough, it explodes right inside the
       | engine bell, pushing the rocket. The proposed design in the
       | original paper is supposed to generate hundreds of gigawatts of
       | thermal power. This is comparable to the Chernobyl reactor #4
       | when it exploded, but unlike Chernobyl (which only exploded once)
       | or the pulsed Orion engine, it could run _continuously_. The
       | stuff that flies out of the nozzle easily reaches escape velocity
       | _of the solar system_.
       | 
       | [1] https://en.wikipedia.org/wiki/NERVA?useskin=vector
       | 
       | [2] https://en.wikipedia.org/wiki/Nuclear_salt-
       | water_rocket?uses...
       | 
       | [3] Obligatory Scott Manley video:
       | https://www.youtube.com/watch?v=cvZjhWE-3zM
        
         | atoav wrote:
         | The nuclear salt reactor one is the answer to the question:
         | "How can we make rocket engine testing more dangerous."
        
         | perihelions wrote:
         | There's one more: the boring idea of combining a closed,
         | electric-generating nuclear fission system with an (electric-
         | powered) ion engine. Both components being flight tested and
         | not crazy.
        
           | jerf wrote:
           | That doesn't sound like something that could get you off of
           | the Earth.
           | 
           | It's probably a great choice for once you're already in
           | space, where being able to apply even very small thrusts
           | nearly-continuously really adds up.
        
       | Laremere wrote:
       | Relevant xkcd: https://xkcd.com/2423/
        
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