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In 1869 a giant space gun was built, with the intent of firing a projectile at the Moon, just to prove that they can do it. Of course, the ludicrous idea to put people inside it was never even taken into consideration, as the acceleration would kill them, and if not, the crash into the Moon, or the lack of an atmosphere would finish with them : it just fired a normal cannon shell.

The experiment was a success, the cannonball hit the Moon and formed a nice little crater, an event being seen and photographed by astronomers. However, as it didn't have any other use, it was quickly abandoned after the first experiment. They coated the interior with wax and put a cover on top of it to keep rust and rainwater away, so it survived mostly intact to his day.

Could we find any useful propose for it? Could it have been of any use in the space race of the 1960's and 70's?

I guess the only benefit is that it's already built by our ancestors so it is completely free: we don't have to spend money and resources for building it. However, as it is built completely vertically, it's not useful to achieve (unaided) orbit around the Earth. Also, the high initial acceleration would probably destroy any sensitive electronics or other equipment we tried to launch with it. Could we design projectiles to limit this? If we can't find any use for it now, could we in the not too distant future?

The only use I might see in it, is to send bulk raw materials to a space station or a Moon colony, but we have neither a Moon colony, nor a space station requiring bulk raw materials.

The cannon is as close to Verne's idea as possible, has a bore with a diameter of nine feet (or slightly less, but not by much), is cast directly and completely into the ground on a hilltop in Florida, is completely vertical, and long enough to be able to be used to hit the Moon with a single explosive charge available in the late 19th century. If the later proves to be physically impossible, then we can modify the original experiment so that the cannonball left the atmosphere, but failed to reach the Moon, instead falling back and splashing into the ocean.

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    $\begingroup$ Related: Why don't we use catapults to get to space? on Space Exploration. (Full disclosure: the accepted answer is my own, although there are several others as well.) $\endgroup$ – a CVn Sep 26 '15 at 13:31
  • $\begingroup$ Some space experiments have consisted in just "shoting" at bodies (satellites, planets) or closely examining natural happening collisions just to see the behavior/composition of those bodies. Of course, there are few things between Earth and Moon, and the Moon has already been throroughly studied. $\endgroup$ – SJuan76 Sep 26 '15 at 13:45
  • $\begingroup$ Today or in the 19th century, we could not see a cannonball collision on the moon with any of our earth-bound telescopes. Just a caveat for your story. $\endgroup$ – Mikey Sep 26 '15 at 17:35
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I think the answer is "no". Even if we could build a payload that would survive the launch and reasonably-soft-land on the moon, there are so many other components which require a more gentle launch. Running both systems in parallel, with the gun for a few supplies and rockets/shuttles for the rest, just isn't cost-effective.

  • The supplies should land very close to the moon base, but not directly on top of the buildings. Minor differences in wind and air pressure during the launch would give major differences on landing.
  • The operation of the gun might be no cheaper than a rocket. Look at the description of the Paris Gun for wear on the barrel.
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  • $\begingroup$ I note that barrel wear was significantly improved by the time of the K5 in WW2. It's still a major consideration though. $\endgroup$ – Green Sep 26 '15 at 13:24
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    $\begingroup$ The OP asked about a Verne-style gun, so the barrel in question is even older. I guess the best they can do is to sell it for scrap and use the money. $\endgroup$ – o.m. Sep 26 '15 at 14:04
  • $\begingroup$ I wish I knew how the barrel wear had been improved upon. If it was metallurgical improvements then absolutely, sell it for scrap and build something else. Probably a combination of things. $\endgroup$ – Green Sep 26 '15 at 14:19
  • $\begingroup$ @Green It is actually explained in general terms in en.wikipedia.org/wiki/21_cm_K_12_%28E%29 Seems it was changes in design not metallurgy. Note that a space cannon would probably not have rifling, so the barrel wear issues would have been less. $\endgroup$ – Ville Niemi Nov 4 '15 at 10:33
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The earth's thick atmosphere is a show stopper for guns to space.

An important quantity is Max Q, the maximum dynamic pressure during flight. Most spacecraft endure a Max Q of around 35 kilopascals.

$q=.5*\rho*v^2$

v is speed, $\rho$ is air density. Doubling speed quadruples q. Tripling speed means a 9-fold increase in q.

Let's say we achieved orbital velocity at the top of Mt. Chimborazo. Dynamic pressure would be 18,000 kilopascals. About 500 times as much as the Max Q a typical spacecraft endures.

A severe hurricane with 160 mph winds has a dynamic pressure of about 3 kilopascals.

To endure an 18,000 kilopascal Max Q, an extremely robust structure would be needed. As well as an extremely robust thermal protection system (Most meteors burn up in the mesosphere 70 kilometers up where the air density is less than 1% that of sea level).

Also 18,000 kilopascals would slow the projectile down. Atmospheric drag would steal a lot of speed before the spacecraft ascended above the atmosphere.

Space guns, slings, rail guns, etc. are much more viable on airless worlds like the moon, Ceres, or Mercury.

Mars is nearly airless and has some very tall mountains. I believe a rail gun from the top of Olympus Mons could achieve orbital velocity.

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  • $\begingroup$ A neat caveat to that rail gun solution: unless you also use a thruster to change your orbit once you're in space, by definition your orbit forms an ellipse which intersects the launcher. If you fired a cannon ball (no thrusters), and we ignored air friction, you could actually strike your launcher in the backside with the cannon ball! $\endgroup$ – Cort Ammon Nov 4 '15 at 20:25
  • $\begingroup$ You're basically describing an artillery shell on steroids. Very big, very slender, it's insane but not impossible. No chemical explosive could exist with the needed power, though--and how many gun-rated payloads would we be interested in sending to orbit, anyway? $\endgroup$ – Loren Pechtel Nov 5 '15 at 21:25
  • $\begingroup$ @CortAmmon Thought here--you can't hit your backside with the cannon ball unless you're on a non-rotating world. $\endgroup$ – Loren Pechtel Nov 26 '18 at 6:32
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The gun's no good for Earth orbit -- it's aimed in entirely the wrong direction. It is, however, quite useful for exploring the Solar System.

Building durable electronics is no problem: accelerating a projectile to 11 km/s over a 300 m distance only requires an acceleration of 20,000 times Earth's gravity, less than what a guided artillery shell experiences.

Once you get out of Earth's gravity well, a solid-fuel booster and possible Lunar flyby will let you get anywhere you want. The inability to launch liquid-fueled engines means you're probably limited to flybys, but the reduced cost of launching means you can fire off a lot of them.

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  • $\begingroup$ The escape velocity of 11.2 km/s is only valid if you discount the atmosphere. Due to atmospheric drag, you would need a much higher muzzle velocity, all but guaranteeing the shell burns up or is torn apart. $\endgroup$ – Cyrus Nov 4 '15 at 9:05
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Unfortunately the inhabitants of the moon resented our unwarranted and indiscriminate shooting at them. They have long memories and are very revenge-minded and having developed the technology they are shooting back. They refuse to negotiate a peace.

We use the original gun but with a modern warhead to subdue them.

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A 19th century gun is simply not capable of accomplishing this--no chemical propellant can provide the required velocity, a cannonball can't hope to make it through the atmosphere. However, the statement is that it works, so lets see what we can do:

We will have to handwave the propellant issue. There's nothing they could have built that would do it. However, the atmosphere is another matter--if you make the gun very big and the shell very long (and dense) you can make it into space. The acceleration is tremendous but could be within the range of current gun-rated electronics so putting something useful in space isn't out of the question.

Another answer dismissed it as useless for putting stuff in orbit but that's not true. You can put something in low Earth orbit for little cost with this--you fire the shell almost straight up, you want it to fall back on a path that skims the atmosphere--you want to scrape off a bit of velocity but not bring it down. Velocity changes at periapsis will lower your apoapsis but leave your periapsis unchanged. (In practice the drag isn't a point source, your periapsis falls a bit but nowhere near what your apoapsis does.) When your apoapsis is low enough you light the solid rocket you brought along to circularize your orbit. Presto, you got a satellite in low orbit with only throwing away a little solid rocket.

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