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Space Transportation Science

A Space Cannon That Might Actually Work 432

Posted by timothy
from the whoooshing-sound dept.
Unequivocal writes "Chalk another one up to Jules Verne. Physicist John Hunter is proposing a space cannon with a new design idea: it's mostly submerged. 'Many engineers have toyed with the [space cannon] concept, but nobody has came up with an actual project that may work. Hunter's idea is simple: Build a cannon near the equator, submerged in the ocean, hooked to a floating rig ... A system like this will cut launch costs from $5,000 per pound to only $250 per pound. It won't launch people into space because of the excessive acceleration, but those guys at the ISS can use it to order pizza and real ice cream.' Though it won't work on people, with launch costs that low, who cares?"
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A Space Cannon That Might Actually Work

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  • by dreamchaser (49529) on Friday January 15, 2010 @08:44PM (#30786252) Homepage Journal

    It'll always be more expensive to send people up, at least in the near term, but we will need to send up a lot of other things that could be done in unmanned launches using this or another innovative technology. Ideas such as this could work; it's merely an engineering problem at this point.

    • Re: (Score:3, Interesting)

      by Anonymous Coward

      For most ideas, feasibility lay entirely on the hands of engineers.

      For example, building a skyscraper 2km tall is merely an engineering problem. A space elevator is merely an engineering problem. A script to automatically discard redundant comments is merely an engineering problem.

      Still, parent's comment is obviusly not discarded.

      • by Kral_Blbec (1201285) on Friday January 15, 2010 @09:05PM (#30786460)
        actually i would say a space elevator is a funding problem.
        • There are still a few engineering challenges left to making one though. For one thing we need a big counterweight, and the 'easiest' way to do that is to tow an asteroid into Earth orbit. I'd say building a space tug is an engineering challenge.

        • by Nyeerrmm (940927) on Friday January 15, 2010 @09:48PM (#30786834)

          Most reputable materials folks I know still claim its a fundamental technology problem, not merely a funding one. While the expected stresses are nominally within what an ideal carbon nano-tube structure can handle, the purity required for that is well beyond what we can manufacture.

          In order to feasibly build a space elevator, we would need much improved nano-technology. Not that I feel that its necessarily an idea-killer -- I'm not terribly knowledgeable on nanotech, but its one of those fields that always surprises me with how fast its going.

        • by pnewhook (788591) on Friday January 15, 2010 @10:31PM (#30787112)

          actually i would say a space elevator is a funding problem.

          Speaking as an aerospace engineer, I would say building a space elevator is a reality problem

          • Re: (Score:3, Informative)

            Well, I can't claim credentials like yours, but lately I've thought that a launch loop [wikipedia.org] would be a much better idea than any of the gun or elevator ideas. It's gentle enough (~ 3g acceleration) to put people in orbit easily, requires no new materials, and supposedly could make multiple launches per day. Your thoughts?
    • by sznupi (719324) on Friday January 15, 2010 @09:06PM (#30786476) Homepage

      http://en.wikipedia.org/wiki/Project_Babylon [wikipedia.org]

      Yes gents, Saddam Hussein could have given us cheap access to space ensuring new area of prosperity for mankind, and era of space colonization...and we killed him!

      PS. If a supergun has a basic design similar to German V-3, it might be almost bearable to humans...

      • by interkin3tic (1469267) on Friday January 15, 2010 @10:07PM (#30786956)

        Yes gents, Saddam Hussein could have given us cheap access to space ensuring new area of prosperity for mankind, and era of space colonization...and we killed him!

        OR Saddam hired a quack who was assassinated before he was revealed to be a complete phoney.

        Had there been something resembling a successful test, I'd say we may have screwed up, but the only mentioned test was a failure. Also I don't hold Saddam's judgment in very high regard, it doesn't sound like there was much peer review on this project, and the US tends to take useful technology and scientific talent from it's enemies rather than destroy it.

        Therefore I doubt this was anything that would have been useful, but I suppose we'll probably never be able to verify or deny your conspiracy theory.

        • by sznupi (719324) on Friday January 15, 2010 @10:44PM (#30787160) Homepage

          The man doesn't seem like a quack to me: http://en.wikipedia.org/wiki/Project_HARP [wikipedia.org]
          Also, the only mentioned test wasn't exactly a failure what I see; it just revealed some problems, which is understandable with such project.

          (and y'know, I was aiming more at Funny...)

          • Re: (Score:3, Interesting)

            by dbIII (701233)
            The same principle works in multistage gas guns used in things like hypersonic shock tunnels and dynamic compaction of metal powder into solids. It works, but I get the impression that for military things explosives or rockets get the job done with less hassle.
            My undergrad thesis supervisor back then worked in the field and actually met this guy at a conference a year or two before he was assassinated.
        • by fm6 (162816) on Friday January 15, 2010 @11:51PM (#30787530) Homepage Journal

          I think anybody on Slashdot who refers to Saddam as the martyred hero of space travel is not being serious.

          If Saddam had taken half the resources he put into exotic weapons and invested in his conventional forces, he'd be alive today — and probably the most powerful man in the Middle East. But training and equipping armed forces is hard work. A lot of dictators just can't be bothered. Instead they model themselves on the villains in James Bond movies: lots of parties, gloating, glitter, and top secret projects, but none of the dreary stuff that has to do with actual governing.

          • Re: (Score:3, Insightful)

            by h4rm0ny (722443)

            Exotic weapons? Saddam Hussein? Uh, citation please.

            Mind, you, I said the same to Colin Powell...
            • Re: (Score:3, Informative)

              by TheRaven64 (641858)

              Depends on what you mean by exotic. If you mean nuclear, there's not much evidence. Well, there's evidence that Saddam put money into developing them, just no evidence that the money bought anything more complex than a centrifuge. There are, however, numerous documented examples of Iraq using chemical weapons, including some tests on their own population. Specifically, they are known to have had sarin, tabun and VX, and may have had others. He also put a lot of money into developing biological weapons [wikipedia.org].

              • Re: (Score:3, Interesting)

                by h4rm0ny (722443)

                Specifically, they are known to have had sarin, tabun and VX, and may have had others.

                Well yes. We still have the receipts for some of those. But he didn't have them at the time. As to conventional forces... I don't think it would have made much difference. The USA had air support. Every time the Iraqis tried to put something in the air or looked like they might, the US blew it to pieces. And anyway, the Iraqi army was never defeated. They just took their uniforms off and the US is still fighting them.

        • by EdIII (1114411) * on Saturday January 16, 2010 @02:24AM (#30788276)

          OR Saddam hired a quack who was assassinated before he was revealed to be a complete phoney.

          What does that remind me of.......

          Doc: Of course, from a group of Libyan Nationalists. They wanted me to build them a bomb, so I took their plutonium and in turn gave them a shiny bomb case full of used pinball machine parts.

          In all seriousness, Saddam only thought he had all of this doomsday projects in the works. The reality, which is supported by evidence apparently (from what I hear), is that most people working for Saddam were terrified of him and his sons and flat out lied or blew smoke up his ass about how far along they were with his ultimate weapons.

          The only thing more tragically retarded and pathetic is the fact that a president and some intelligence agencies fell for the same bullshit. Or did they? :)

      • PS. If a supergun has a basic design similar to German V-3, it might be almost bearable to humans...

        No. If you work out the G forces required at launch to ballistically get into orbit, solid objects such as electronics will not survive. Live subject would not have a chance.

        • by sznupi (719324) on Saturday January 16, 2010 @12:18AM (#30787632) Homepage

          First of all, you can't get into stable orbit ballistically; you have to use a rocket motor at apogee of ballistic trajectory, at the least.

          Also, we do have clear examples of electronics (from the 60's...) surviving launch to half of orbital velocity from a modified big naval cannon (Project HARP). And that's more or less a "normal" cannon, very short, very high acceleration. Look up V-3; such design can maintain almost constant acceleration, close to average one, and be hypothetically several kilometers long.

          So why don't we go totally overboard, and assume a barrel length of 30km; and close to half of orbital velocity (so it will be easier, since there's ^2 in this part of equation ;p) - 3.5 km/s. From simple calculations that gives 20 g. Definitely bearable, as far being launched from a cannon into space goes. With 5 km/s you have 42 g.

          Yes, widely unpractical and even...stupid. But I didn't actually suggest using it for humans, just said that it might be almost bearable.

    • by the_Bionic_lemming (446569) on Friday January 15, 2010 @09:12PM (#30786536)

      Who's going to buy the tylenol for the whales?

      Acoustics are a bitch.

  • Ice cream? (Score:2, Insightful)

    by Xamusk (702162)
    I wonder how ice cream would get after those accelerations
    • Re: (Score:3, Funny)

      by RobVB (1566105)
      Milkshake.
    • Re: (Score:3, Informative)

      by wizardforce (1005805)

      Seeing as ice cream is an emulsion if it gets warm enough it could fractionate into a much less tasty brew. However, if you keep ice cream very, very cold, it shouldn't be terribly affected by the g-forces if packaged properly. The real problem is what to do with real ice cream in an environment like the ISS where real ice cream can cause problems by virtue of the fact that loose fluids and crumbs need to be kept at a minimum for various reasons.

    • Re: (Score:3, Insightful)

      by icebike (68054)

      Actually there is very little in the way of supplies that could handle that acceleration. Maybe freeze dried soup, maybe water, but very little else. You wouldn't dare send gasses, electronics, whole foods (even canned) or replacement parts.

      The whole idea hinges on the un-compressibility of water, making the extra long cannon easier to construct, but if you've ever seen a depth charge explode you know that only works so far. It also mentions an increase of pressure of 500% which is no where near enough.

      • Re: (Score:3, Informative)

        by Dare nMc (468959)

        This was short on details, but the military builds electronics into some bullets that function at 15,000 G's [wikipedia.org]. Napkin math says that would need a 1 mile long barrel to reach the 13k mph quoted in the article. if it was 5 miles long your 3500 G's you could launch about anything submerged in a liquid (typical wrist watch survives this without the liquid.) So about the only thing they couldn't launch is something living.
        But even at 1/2 mile their still under the accelertion of a gun, so wouldn't even deform

    • by Ungrounded Lightning (62228) on Friday January 15, 2010 @09:51PM (#30786854) Journal

      Make it long enough and it CAN launch people. (You'll need good streamlining to avoid nasty deceleration when it leaves the muzzle, though.)

      The ocean is DEEP. Something that's roughly neutrally buoyant (i.e. a gun barrel supported by floats distributed along its length) needs to spend negligible structural strength supporting itself. (It only needs to be strong on any part that protrudes from the water - which might be a lot to avoid sinking it when it recoils.) You might want to put "helper combustion chambers" along it periodically to boost and smooth the acceleration if you want to launch live stuff though.

      Also you can make it larger diameter and put sabots on the projectile while it's in the barrel to reduce the internal pressure variations or fire very dense loads. (Doesn't really help the materials strength issues, though, because the curvature lessens as diameter rises.)

      Recoil? By being submerged it's an inside-out hydraulic shock absorber. B-)

      • Re: (Score:3, Informative)

        by jklovanc (1603149)

        A bit of math here. Escape velocity on earth is 10.735Km/sec, Acceleration at 6G = 9.8*6=58.8 M/Sec^2. 10735/58.8 = 182.5 Second to reach escape velocity
        Distance travelled during that that time 10.735*182.5/2 = 979 Km. Basically to accelerate a body to escape velocity with a steady 6G acceleration would require a tube almost 1000 KM long. Even popping up to 10G the tube would be 585Km long.

        These calculations do not even take into consideration deceleration due to drag.

        By the way, escape velocity is approxim

  • by hyades1 (1149581) <hyades1@hotmail.com> on Friday January 15, 2010 @08:47PM (#30786280)

    The last guy with a plan to build a super-cannon (a Canadian named Bull) did some work for Saddam Hussein. The Israelis didn't like that much, so they murdered him.

  • by sakdoctor (1087155) on Friday January 15, 2010 @08:47PM (#30786292) Homepage

    I want to order pizza and ice cream on earth, delivered by cannon.

  • by 192939495969798999 (58312) <info.devinmoore@com> on Friday January 15, 2010 @08:48PM (#30786300) Homepage Journal

    it works on people, so long as they're already dead. Why does this matter? Because now I can get the Star Trek space-burial I always wanted!

  • by DotDotSlashDot (1207864) on Friday January 15, 2010 @08:49PM (#30786302)
    This subject line says it all when it comes to efficiently placing things in low earth orbit.
    • The reason space is expensive has more to do with the complexity of the rocket engines and the companies that build them than the propellant. If you want cheap access to space, focus on that. Capital-intensive projects that put heavy wear on their components (like guns) won't make things cheaper. The goal should be to *reduce* the number of parts that need maintenance.
  • Google Tech Talks (Score:5, Informative)

    by Anonymous Coward on Friday January 15, 2010 @08:49PM (#30786304)

    Here is an interesting "tech talk" at Google where John Hunter explains the workings of the cannon:
    http://www.youtube.com/watch?v=1IXYsDdPvbo

  • atmospheric stresses (Score:5, Interesting)

    by wizardforce (1005805) on Friday January 15, 2010 @08:53PM (#30786342) Journal

    If you try to launch an object from the surface of the Earth using a "cannon" the projectile won't be doing anything other than decelerating throughout its flight and this means bringing the projectile to very high velocities where atmospheric heating and stresses become major problems. Then again, launch its self may be a problem as the Hydrogen propelling the projectile is detonating at an extremely high temperature and pressure. Small nitpick as well from TFA:

    but those guys at the ISS can use it to order pizza and real ice cream.

    A big reason space food is what it is instead of the Earthling food we're all accustomed to has to do with keeping the station reasonably clean and experiments doubly so. Crumbs and fluid loose in the station can cause problems.

  • Since the business end is floating, one could assume that it could be moved. ie: you can aim it. Sure, you could put a pizza into orbit... or not quite.

    "Nice, er... gun... you have there."

  • Why launch pizza and ice cream, which might not withstand the 5000 G acceleration when you can launch a bunch of cubesats or microsatellites. In fact there's a microsatellite(it's name escapes me) up there that's a web server. If you have some amateur radio equipment you can download and upload files to it. It can't store much, only enough for about an email or so. But with improvements in electronics it'll be possible to store even more data on a microsatellite. So eventually the Pirate Bay or Wikileaks
  • Velocity (Score:3, Informative)

    by Sperbels (1008585) on Friday January 15, 2010 @09:01PM (#30786424)
    Correct me if I'm wrong, but 13,000mph isn't fast enough for any kind of stable orbit.
    • Who says it has to be stable? It just has to get high enough for the ISS to snag it.
    • If you could get through 99.99% of the earth's atmosphere your propulsion methods are much broader. If half your payload was fuel I imagine you could get to a higher orbit pretty easily.

    • Re:Velocity (Score:5, Interesting)

      by malakai (136531) on Friday January 15, 2010 @09:37PM (#30786736) Journal

      Min orbital velocity = 7.6 km/s
      Earth Escape Velocity = 11.2 km/s

      Funny coincidence, world record for hydrogen gun == 11.2 km/s

      These guys plan to have the gun propel the projectile to 6.0 km/s, and then the projectiles themselves are rocket motors that will add an additional 3.0 km/s. That gives them enough acceleration to reach orbital velocity and take into account friction/gravity losses.

      The reason they plan to limit the gun to 6.0 km/s is because that requires the hydrogen gas to only reach 1700 kelvin, which after taking into account heat exchange with the barrel, it ends up being a few hundred kelvin below the melting point of steel ( the barrel ).

  • by jandrese (485) <kensama@vt.edu> on Friday January 15, 2010 @09:03PM (#30786442) Homepage Journal
    I don't suppose the $250/lb launch costs include the build cost amortized over the lifetime of the system? Or the maintenance costs for that matter. The cost per pound on rockets includes those factors, and far too many people only work up the cost of electricity or whatever when working out the "launch cost" of one of these schemes.

    In the end, once you've figured up the total cost of the system it's often more than just using rockets, even though rockets are so terribly inefficient.
    • by RobVB (1566105)

      If prices go from $5000/lb to $250/lb, demand for these launches will skyrocket (ha ha). If they launch often, maintenance and amortization costs can be shared by many clients, meaning they can keep the prices that low.

      The launch costs might be based on an overly optimistic demand, though.

      • Re: (Score:3, Insightful)

        by rahvin112 (446269)

        To fire it from a cannon the G force is going to be astronomically high. Very little is going to be able to survive that type of acceleration without massive damage. You could certainly fire a block of metal that fast without worry that it's ruined (though it will likely deform) but you put a 2 billion satellite in that and it's going to be absolutely destroyed by the acceleration. Even with a conventional rocket they spend several million dollars packing and testing the container the satellite is shoved in

        • Re: (Score:3, Insightful)

          by Carnildo (712617)

          To fire it from a cannon the G force is going to be astronomically high.

          5000 G. That's about the equivalent of dropping something out a third-story window onto a concrete surface. Your laptop won't survive it, but bulk supplies (food, water, oxygen) will. Properly-designed equipment will as well: when your laptop hits the ground, it's not the computer chips themselves that break, but the joints -- electronic fuses in artillery shells don't have any trouble. You could even put entire satellites into orbi

    • by malakai (136531) on Friday January 15, 2010 @09:25PM (#30786628) Journal

      10 mins into the Google Tech Talk he gives a slide with the amortization cost per lb. About 20 mins in, he breaks the project up into phases and costs needed to complete each phase.

      http://www.youtube.com/watch?v=1IXYsDdPvbo [youtube.com]
      It's worth watching the video for more info on G-Force hardening, Hydrogen re-capture, per-lb cost and project milestone/costs.

  • by Anonymous Coward

    Though it won't work on people...

    I'm sure it would launch people just fine.

  • Terrible article (Score:5, Informative)

    by QuantumG (50515) * <qg@biodome.org> on Friday January 15, 2010 @09:15PM (#30786562) Homepage Journal

    Wow, that article is horrid. They don't even mention Hunter's startup company: Quicklaunch [quicklaunchinc.com]. On that page you'll find his Google Tech Talk on the subject which answers many of the questions that people are asking here.

  • by michaelmalak (91262) <michael@michaelmalak.com> on Friday January 15, 2010 @09:54PM (#30786892) Homepage
    In my experience, pizza holds up less well to acceleration than people do.
  • by DaveAtFraud (460127) on Friday January 15, 2010 @10:35PM (#30787138) Homepage Journal

    Sorry, but I don't see the benefit of floating the cannon in the ocean. You have a very long structure that must be kept really close to perfectly straight that is subject to currents, waves, coriolis effects, etc. Worse, you are stuck with the projectile emerging into the densest part of the earth's atmosphere.

    It would make a lot more sense to build a fixed structure on an appropriate, high mountain near the equator. Places like Peru or Ecuador come to mind as well as Mauna Kea on Hawaii. I'm sure there are more places that would be "developable" and logistically acceptable.

    Cheers,
    Dave

    • Re: (Score:3, Interesting)

      If you watched the google talk he gave, you'd know the difference between mountain and sea level launch is just 0.5 km/s. And the heavier the projectile is the less air resistance matters.
    • Re: (Score:3, Informative)

      by Anonymous Coward

      Sorry, but I don't see the benefit of floating the cannon in the ocean.

      1. You can aim it. This is a big fucking deal

      2. Weight is not a factor. You can build your cannon as heavy and as strong as you please.

      3. You don't have to worry about safety because any failures will happen underwater and away from land. This is also a big fucking deal

    • Re: (Score:3, Interesting)

      by MartinSchou (1360093)

      As some people have pointed out, most of the things you mention aren't problems. Loss of speed, straightness of barrel etc. Plus, as they say, you get to aim for different orbits in one platform

      One thing they didn't point out which is significant: Logistics.

      You go ahead and bring huge supply train up the side of Mauna Kea - I'm sure none of the neighbours will mind. As someone else pointed out, I'm sure they wont mind when something goes tits up and you send shrapnel towards them at a km/s.

      Logistics are a k

  • by Fnord666 (889225) on Saturday January 16, 2010 @02:00AM (#30788184) Journal
    The original Popular Science article [popsci.com] is a much better read and includes additional detail, including the fact that the projectile will experience 5,000G forces. Definitely not for human passengers.
  • by j_w_d (114171) on Saturday January 16, 2010 @03:26AM (#30788502)
    Great, this could put a whole new light on lost baggage: "Dear Mr. Jones. Your baggage was fired Tuesday. It should have arrived at the ISS before you did. Unfortunately, the capture system failed. The capsule has entered an unstable, atmosphere grazing orbit and will burn upon re-entry in about two weeks. We're sorry, but this loss is covered in the waiver you signed. Sincerely, A. Pratt"
  • ASAT weapon (Score:3, Informative)

    by amightywind (691887) on Saturday January 16, 2010 @11:14AM (#30790394) Journal

    I never cease to be amazed of some of the silly things that are published on Slashot.

    A system like this will cut launch costs from $5,000 per pound to only $250 per pound. It won't launch people into space because of the excessive acceleration, but those guys at the ISS can use it to order pizza and real ice cream.

    The ISS obital inclination is 56 degrees. Any 'ice cream delivery' made from a 0 degree inclination transfer orbit would have a relative velocity of about 7500 mph. The ice cream would effectively become an ASAT weapon.

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