Jules Verne Cannon Payload To Orbit.... Feasible?

[Spacescifi]

The idea is to make an underground shaft and detonate a shaped charged nuke into a pusher plate spacecraft equipped with nonmanned payload.

Once in space the ship jettisons the pusher plate assembly, and flips over to boost to orbit or wherever with rocketry.

 

The heavier the better... up to a point. Ship must be heavy enough to survive ablation, but light enough to boost off a single nuke into outer space.

Pros: One detonation... not multiple as with project Orion.

Large mass can indeed survive as air thins out the higher you go.

 

Bonus advanced version: Mega nuke cannon boost to orbit, no rocket booster required to stabilize orbit?

Anyone dare to calculate the feasibilty of either concept?

In my opinion both are, and easier than project orion.

You just send up crew via normal rockets, but the entire ship they will stay in is boosted into into orbit with the nuke cannon.

 

 

What do you think?

Less fallout? Yep.

 

Controlled detonation? Yep.

 

Better for safety than project orion with massive payload to orbit? Yes.

 

 

Edited November 6, 2021 by Spacescifi

[KSK]

Bonus version either doesn't work or requires a complicated trajectory to reach a stable orbit.

If you're firing into orbit, you're firing into a closed trajectory by definition. The problem is that any closed trajectory starting from the ground finishes at the ground, so at best you get a single orbit then kaboom. Conceptually, the easiest way to avoid that is a rocket burn at apogee (highest point on the orbit) to raise perigee (lowest point on the orbit) to an altitude above the atmosphere.

The complicated way involves maths and visualisation skills that are beyond me but apparently in a three body system (e.g. Earth, Moon, Sun) it's possible to use the the gravitational fields of the other two bodies to effectively do that orbit raising for you. I have no idea how often the Earth, Moon and Sun line up in just the right configuration for that to work though.

Edited November 6, 2021 by KSK

[magnemoe]

14 minutes ago, KSK said:

Bonus version either doesn't work or requires a complicated trajectory to reach a stable orbit.

If you're firing into orbit, you're firing into a closed trajectory by definition. The problem is that any closed trajectory starting from the ground finishes at the ground, so at best you get a single orbit then kaboom. Conceptually, the easiest way to avoid that is a rocket burn at apogee (highest point on the orbit) to raise perigee (lowest point on the orbit) to an altitude above the atmosphere.

The complicated way involves maths and visualisation skills that are beyond me but apparently in a three body system (e.g. Earth, Moon, Sun) it's possible to use the the gravitational fields of the other two bodies to effectively do that orbit raising for you. I have no idea how often the Earth, Moon and Sun line up in just the right configuration for that to work though.

Yes you will always need an circulation burn for an rail launch system as Pe will be at attitude of launch site. 
Now its true that many modern rockets upper stage does not do an KSP style circulation burn, but this is because the burn time is long and you have planned the burn well so you simply merges circulation into the main burn. If you goes to an higher orbit you need an circulation burn but for stuff like GEO the satellite tend to do that themselves. 

[magnemoe]

Ad for the idea, it has been some ideas using railguns. However as lauch costs goes down I don't think its realistic. 
The nuclear cannon probably work, you need artillery shell level ruggedness however so mostly raw materials and rugged items. 

Now on the moon you could build an coil gun launcher who sounds much more practical, you build this as an maglev train but with much higher acceleration. 
You will need to circulate, now it would be stupid to have this hit the base if circulation failed
If you goes all the way to L1, you will still need an burn but probably an very small one. 
You will have to land the capsule again for reuse but then they would be empty.  Another option is to make the crude cast aluminum pods part of the payload and simply return the fight systems. 

[wumpus]

13 minutes ago, magnemoe said:

Yes you will always need an circulation burn for an rail launch system as Pe will be at attitude of launch site. 
Now its true that many modern rockets upper stage does not do an KSP style circulation burn, but this is because the burn time is long and you have planned the burn well so you simply merges circulation into the main burn. If you goes to an higher orbit you need an circulation burn but for stuff like GEO the satellite tend to do that themselves. 

Except the Baltimore Cannon (rocket?) Club was going to the Moon and could use a gravity capture to circulurize.

The bigger problems were the required size of the cannon, the rate of expansion of the "exploding gasses" (not sure if they used nitrocelluouse, dynamite, or gun powder, but the'd need multiple dynomite explosions expanding hydrogen gas to make it work).

And as no surprise, Scott Manley had already answered your question.

 

[Admiral Fluffy]

4 minutes ago, wumpus said:

Baltimore Cannon (rocket?) Club

Baltimore gun club, I believe.

[wumpus]

It might have been possible  for a Victorian "steampunk" society to get to orbit off a planet with a mass like Kerbin (orbital velocity ~3km/s), but never Earth.  Expect to require both a cannon and multiple gunpowder-based (or perhaps give then WWII-era solid rocket tech, I don't think it required a 20th century infrastructure) rocket stages to get to orbit.

Look up spin-tech for current attempts to achieve "first stage delta-v" on Earth.  Railgun launches would also be ideal for ramjet/scramjet "second stages".  In general, this is "tech that won't be needed until getting into orbit is routine, and you want to reduce fuel costs" (and other launch costs are cheap) which is 2100 by the NASA calendar or 2030 by Elon time.

[kerbiloid]

Depends on the launch site.

Spoiler

If place it in Yellowstone, it can reach even Mars.

 

[magnemoe]

7 minutes ago, Admiral Fluffy said:

Baltimore gun club, I believe.

That is correct, however an gun club make me think of an organisation who own an range not someone who make an gun who makes Heavy Gustav

look small, its an 80 cm bore gun and its sit between two railway carriages, 80 cm is 31.5 in or just .5 in below double the bore of an 16" gun used on the last generations of US battleships including the Iowa's. I say gun laws was more relaxed back then  
More seriously they got special permits. SpaceX can launch larger rockets than you. Companies making weapons obviously need to test them. Read a article once with one working in an company making among other thing surface to air missiles and other military stuff. 
Now the fun part is that they had an company learjet modified to launch missiles. Outside of the console to launch it was an standard private jet and was used for this.
Then they did test launches they hooked up a lot of logging servers and laptops. 

[TheSaint]

Can't believe we're ten posts in and nobody has mentioned Gerald Bull, Project HARP, or Project Babylon.

[mikegarrison]

The three fundamental problems are:

1. As mentioned, an orbit that starts on the ground will have a perigee on the ground, so you need to do more than just "fire a gun to orbit".
2. Unlike a rocket launch, your projectile will have its highest speed low in the atmosphere, where it has the most drag and shock heating .
3. Your projectile must gain all its speed in a very short time, which means a massive acceleration. It would have to be built very stoutly indeed, and certainly nothing living is likely to be able to survive such acceleration.

[Lisias]

1 hour ago, mikegarrison said:

The three fundamental problems are:

Only three?  I can think at least two more! But some with reserves...

 

1 hour ago, mikegarrison said:

1. As mentioned, an orbit that starts on the ground will have a perigee on the ground, so you need to do more than just "fire a gun to orbit".

Yep. But if you are aiming the orbit of another celestial body that not the origin, you can accomplish that - with limitations, obviously.

 

1 hour ago, mikegarrison said:

1. Unlike a rocket launch, your projectile will have its highest speed low in the atmosphere, where it has the most drag and shock heating .

What's a problem only inside atmospheres. Obviously the OP implies launching from Earth, as it's done on Julio Verne's work, but we don't need to limit ourselves to it.

"Shooting" something from Moon to Earth is feasible, even if not vice-versa.

 

1 hour ago, mikegarrison said:

1. Your projectile must gain all its speed in a very short time, which means a massive acceleration. It would have to be built very stoutly indeed, and certainly nothing living is likely to be able to survive such acceleration.

This is were you may had missed the point - cannons usually works by lighting up an unique, big and massive keg of explosives to impulse the projectile out of the barrel.

But it doesn't have to be this way.

In fact, the Germans had developed a kind of cannon where the projectile was kicked out from the huge barrel by a series os smaller explosions, each one adding up from the last. Pretty interesting, pretty impressive, and this idea can be useful on our thesis:

Source: https://en.wikipedia.org/wiki/V-3_cannon

About the points I think you had missed:

• The cannon, or better, the barrel, is the critical part of the solution (and not the projectile)
  • It must be strong enough to withhold all the kinetic energies dissipated by the explosion(s) and, au contraire of the projectile, it must be reusable. A lot of times.
• Launching is only half of the problem - landing is the part of the mission that's really matters, and it's a lot harder on a ballistic approach.

What doesn't means the idea is totally meritless.

I can think on a way to use this to send raw materials from Mün Moon to Earth, by example. Powder and Oxygen are not the only way to kick mass from a barrel, there're other ways that can do it from an atmosphere-less environment, as nuclear-powered heaters vaporising water or some other element that explosively expands when heated fast enough.

(Mass drivers are cool, but I don't think they will be powerful enough for this task)

So, I think the following scenario may be plausible:

1. You establish a mining operation on Moon for some rare and highly needed ore
2. You fill a keg with such material, shove it on a really big barrel full of chambers for highly explosive gas expansion (probably by nuclear heaters)
3. You fire the damn thing into a trans-earth injection straight from the ground.
4. Trough careful calculations, you aim the keg to a shallow reentry on the atmosphere, probably doing more than one aerobrake pass.
5. The thing must have a minimum set of manoeuvrability in order to control the process and avoiding overshooting or undershooting the target area (you don't want some tons of ore landing on the Central Park in New York!)
   1. So the need for a longe barrel where each impulsive explosion doesn't exceeds the limits of the hugged (to a limit) controlling devices.
6. You target some shallow waters or even some soft land (it's ore! you can easily clean up the raw materials before using it), and then you just recover the debris remains ore from the landing crashing lithobraking site.
   1. The capsule doesn't needs to be reusable, only the cannon itself.
7. ????
8. Profit!

(I'm pretty sure I had read something similar on some scify magazine or science speculation site or something in the past, besides not remembering it.)

Edited November 7, 2021 by Lisias
Hit "Save" too soon.

[mikegarrison]

28 minutes ago, Lisias said:

This is were you may had missed the point - cannons usually works by lighting up an unique, big and massive keg of explosives to impulse the projectile out of the barrel.

No, the point is that a rocket launch takes place over a span of minutes. Even with a very long barrel, a gun launch takes place over a span of seconds. That necessarily implies that if you reach the same speeds, the accelerations must be quite a bit higher in a gun launch.

The big advantage of a gun launch, however, is that it avoids the tyranny of the rocket equation. You don't have to accelerate all your propellant along with your projectile.

Edited November 7, 2021 by mikegarrison

[Lisias]

8 hours ago, mikegarrison said:

No, the point is that a rocket launch takes place over a span of minutes. Even with a very long barrel, a gun launch takes place over a span of seconds.

And that's make a huge difference!

For the sake of simplification, let's ignore the atmosphere and the perigee. Let's focus only on the speed needed to reach orbit (~11KM/sec) and the time you take to reach it.

Using a single, huge explosion to reach orbit would subject the capsule to 11K/9.8 =~ 1.122Gs of instant acceleration. That would crush any material I can think of. Put something on Neptune's equator and see what happens - same thing.

Now, instead of a huge explosion, lets take a 100 meters barrel with 11 explosion chambers (the initial one, and one each 10 meters). On a naive calculation (it's late night), each impulse is now "only" 11K/11 = 1Km/s, or ~102Gs. Still fatal for humans (we are usually killed over 50Gs).

So, instead of 11 explosion chambers, lets use 101 explosion/expansion chambers on the same 100M barrel, what gives us ~11Gs on each explosion. Extremely uncomfortable, but perfectly survivable by fighter pilots that are trained to withhold 9G for seconds and still be functional.

But that is still rough as hell.

How about, so, 201 explosions/expansions over 200 meters? Well, we would have about 6Gs on each "stage". That's the G forces the Apollo astronauts had to endure on reentry, and an reentry lasted minutes.

[Uhh. Nope. Trying to do math late night is far from being wise..  ]

Of course, I'm solemnly ignoring friction as we would loose some energy spreading the acceleration over 200 meters inside a tube (as well some other losses I'm not accounting, as the gravity losses while ascending - we need 11K/s "up there", not on the barrel's exit point), but yet the overall idea is there.

Edited November 7, 2021 by Lisias
uhh… nope. :)

[mikegarrison]

23 hours ago, Lisias said:

And that's make a huge difference!

For the sake of simplification, let's ignore the atmosphere and the perigee. Let's focus only on the speed needed to reach orbit (~11KM/sec) and the time you take to reach it.

Using a single, huge explosion to reach orbit would subject the capsule to 11K/9.8 =~ 1.122Gs of instant acceleration. That would crush any material I can think of. Put something on Neptune's equator and see what happens - same thing.

Now, instead of a huge explosion, lets take a 100 meters barrel with 11 explosion chambers (the initial one, and one each 10 meters). On a naive calculation (it's late night), each impulse is now "only" 11K/11 = 1Km/s, or ~102Gs. Still fatal for humans (we are usually killed over 50Gs).

So, instead of 11 explosion chambers, lets use 101 explosion/expansion chambers on the same 100M barrel, what gives us ~11Gs on each explosion. Extremely uncomfortable, but perfectly survivable by fighter pilots that are trained to withhold 9G for seconds and still be functional.

But that is still rough as hell.

How about, so, 201 explosions/expansions over 200 meters? Well, we would have about 6Gs on each "stage". That's the G forces the Apollo astronauts had to endure on reentry, and an reentry lasted minutes.

Of course, I'm solemnly ignoring friction as we would loose some energy spreading the acceleration over 200 meters inside a tube (as well some other losses I'm not accounting, as the gravity losses while ascending - we need 11K/s "up there", not on the barrel's exit point), but yet the overall idea is there.

 

That just doesn't work.

For constant velocity v, a projectile covers s distance in t time. s = vt

But starting from rest, it only covers half that distance, so s = 1/2 vt. We know v and s, which means the time for the projectile to reach 11 km/s in 0.1 km is .2/11 = 0.0182 seconds.

To get to 11 km/s in 0.0182 seconds, the average acceleration necessary to do that is 605000 m/s², or almost 62000 g. And that's assuming you have divided up your acceleration as finely as possible.

=========

ps. I see the problem in your reasoning there. You are forgetting that acceleration is m/s/s. Look at the units you are using and your calculations are missing the time.

"11K/11 = 1Km/s, or ~102G"

But no, 102 g is not 1 km/s. It is 1 km/s/s

So you need to include the amount of time you take to apply that acceleration, and that means dividing by a very small number, which means multiplying your "g"s by a large number.

Edited November 8, 2021 by mikegarrison

[kerbiloid]

Even a thousand-kilometer long rocket path requires ~4g acceleration.

[sevenperforce]

3 hours ago, Lisias said:

Using a single, huge explosion to reach orbit would subject the capsule to 11K/9.8 =~ 1.122Gs of instant acceleration. That would crush any material I can think of. Put something on Neptune's equator and see what happens - same thing.

Math issues aside, a quick note here: 1,122 gees is a lot — far more than puny meatbag humans can handle — but it is not that bad from an engineering standpoint. An ordinary shock-resistant wristwatch can handle 5,000 gees and there are hardened electronics rated to 15,000 gees. 

4 hours ago, mikegarrison said:

The big advantage of a gun launch, however, is that it avoids the tyranny of the rocket equation. You don't have to accelerate all your propellant along with your projectile.

Yes, but on the other hand, you are hard-limited to the speed of sound in your combustion gases, which is why you eventually need to go to a light gas gun to get really high velocities.

What would be really cool would be a way to design a continuous-detonation-wave gun, where the projectile “surfed” a steady-state detonation wave behind its tail. Detonation waves are of course not limited by the speed of sound. 

[mikegarrison]

14 minutes ago, sevenperforce said:

Math issues aside, a quick note here: 1,122 gees is a lot — far more than puny meatbag humans can handle — but it is not that bad from an engineering standpoint. An ordinary shock-resistant wristwatch can handle 5,000 gees and there are hardened electronics rated to 15,000 gees. 

Yes, but on the other hand, you are hard-limited to the speed of sound in your combustion gases, which is why you eventually need to go to a light gas gun to get really high velocities.

What would be really cool would be a way to design a continuous-detonation-wave gun, where the projectile “surfed” a steady-state detonation wave behind its tail. Detonation waves are of course not limited by the speed of sound. 

Well, or just use electromagnetic propulsion.

However, as Scott Manley pointed out in his video, you really want to be doing this on the Moon. Otherwise you are having to push all the air in the barrel out in front of you. This is why the standard application for this sort of thing in SF stories is EM launchers from the Moon. You have about 1/6th the surface gravity and no air to impede your launch. (You may have something of a heat dissipation problem, however. Convenient heat sinks on the Moon are hard to come by.)

[Lisias]

6 hours ago, mikegarrison said:

ps. I see the problem in your reasoning there. You are forgetting that acceleration is m/s/s. Look at the units you are using and your calculations are missing the time.

yep. Now in the morning, I reached the same conclusion. Had I remembered that you get about 3G of accelerations on launching Space Shuttle would had hinted me about the issue.

'For every complex problem, there's a least one solution that's easy, elegant... and  completely wrong.'

3 hours ago, mikegarrison said:

Well, or just use electromagnetic propulsion.

I don't think mass drivers will cut it. Every time you convert a form of energy into another you have a lot of losses.

For that amount of energy, converting from nuclear energy will be the most probable source. So it will be more efficient to use the energy directly into a expansion gas for propulsion than using it to prop a turbine (losses) that will prop a generator (more losses) than will energize cables (more losses) that will drive some kind of superconductors that will do the job. And since superconductors need some serious cooling, you will have to divert a decent part of that electricity to it (yet more losses).

 

 

4 hours ago, sevenperforce said:

Math issues aside, a quick note here: 1,122 gees is a lot — far more than puny meatbag humans can handle — but it is not that bad from an engineering standpoint. An ordinary shock-resistant wristwatch can handle 5,000 gees and there are hardened electronics rated to 15,000 gees. 

It depends of the mass. It's not the Acceleration that kills you exactly, but the forces transfer between your cells - your soft tissues against your harder tissues, to be more specific.

About the clock, Net Force = Mass times Acceleration (Newton's second - thanks, Wikipedia!). The wristwatch would not handle that 5K gees if it would have the mass of my grandma's swinging pendulum clock.

I will stay away from heavy Maths for while (coffee still kicking in), but a wristwatch weights about 160g. If a given wristwatch sustain 5K gees, it can withhold about 5.000 * 9.8m/s² * 0.160kg = 7840N. So the magic number is 7840.

I think a long case clock may weight about 25kg (~15kg only for the weight on the pendulum!). So… 7840N = Xm/s² * 25kg => X = 7840/25 => X = ~314M/s/s, or "merely" 32G.

Again, this is a oversimplification: a wristwatch is not made of a uniform material - a shockproof wristclock will not disintegrate over an impact of 5000Gs, what will happen is that its weakest part will brake apart at 5K gees. But if that weakest part would be about 160 times heavier, it would break apart at 1/160 the original gee resistance - what's another oversimplification, as resistance of materials doesn't scales linearly!

Edited November 7, 2021 by Lisias
Brute force post merging

[Spacescifi]

10 hours ago, Lisias said:

yep. Now in the morning, I reached the same conclusion. Had I remembered that you get about 3G of accelerations on launching Space Shuttle would had hinted me about the issue.

'For every complex problem, there's a least one solution that's easy, elegant... and  completely wrong.'

I don't think mass drivers will cut it. Every time you convert a form of energy into another you have a lot of losses.

For that amount of energy, converting from nuclear energy will be the most probable source. So it will be more efficient to use the energy directly into a expansion gas for propulsion than using it to prop a turbine (losses) that will prop a generator (more losses) than will energize cables (more losses) that will drive some kind of superconductors that will do the job. And since superconductors need some serious cooling, you will have to divert a decent part of that electricity to it (yet more losses).

 

 

It depends of the mass. It's not the Acceleration that kills you exactly, but the forces transfer between your cells - your soft tissues against your harder tissues, to be more specific.

About the clock, Net Force = Mass times Acceleration (Newton's second - thanks, Wikipedia!). The wristwatch would not handle that 5K gees if it would have the mass of my grandma's swinging pendulum clock.

I will stay away from heavy Maths for while (coffee still kicking in), but a wristwatch weights about 160g. If a given wristwatch sustain 5K gees, it can withhold about 5.000 * 9.8m/s² * 0.160kg = 7840N. So the magic number is 7840.

I think a long case clock may weight about 25kg (~15kg only for the weight on the pendulum!). So… 7840N = Xm/s² * 25kg => X = 7840/25 => X = ~314M/s/s, or "merely" 32G.

Again, this is a oversimplification: a wristwatch is not made of a uniform material - a shockproof wristclock will not disintegrate over an impact of 5000Gs, what will happen is that its weakest part will brake apart at 5K gees. But if that weakest part would be about 160 times heavier, it would break apart at 1/160 the original gee resistance - what's another oversimplification, as resistance of materials doesn't scales linearly!

 

Ouch... so once again, it is a lot harder than it seems.

 

If we attempted to say.... use an uber nuke cannon to launch the second stage of starship into space, where it will stabilize it's own orbit... that may work... but it would involve a far more durable and more expensive version. Lighter weight increases high g-force survivability, but that is kind of the antithesis of the whole point of nuclear cannon launch.

 

When it comes to g-force you are only as strong as your weakest link.

 

For example, I guarantee you high g-force will always crush your organs before your bones.

Since bonee are more durable.

If one launched an unmanned starship second stage via nuclear cannon, all of it would have to be g-force hardened, down to the most delicate components.

A vessel is only as strong as it's weakest link. If that breaks you may as well say goodbye to the rest of it since it will cause a multitude of problems down the line. It is like a small crack that spreads exponentially.

Edited November 7, 2021 by Spacescifi

[wumpus]

21 hours ago, TheSaint said:

Can't believe we're ten posts in and nobody has mentioned Gerald Bull, Project HARP, or Project Babylon.

Basically because of the extreme limitations already covered in this thread.  You'll still need a [presumably solid, to survive multip-thousand-g-forces] a second or third stage, which means you gun has to be big enough to be largely launching a [second stage] booster instead of launching a spacecraft.  Compare to air launch, which trades large mass (and volume, and often the ability to "top up" lox or lh2)  requirements to allow a much larger bell and less air resistance while launching.  Two companies have successfully done air launch (Orbital and Virgin Orbital.  Did a MiG ever launch something into orbit or simply demonstrated anti-satellite capability?), but nobody has gotten close to cannon launch.

I still like the idea of launching a SCRAMJET with a railgun.  Not that the tech is remotely ready, but NASA *did* demonstrate a working SCRAMJET already, and the rail accelerators are even used to launch roller-coasters

[TheSaint]

3 hours ago, wumpus said:

Basically because of the extreme limitations already covered in this thread.  You'll still need a [presumably solid, to survive multip-thousand-g-forces] a second or third stage, which means you gun has to be big enough to be largely launching a [second stage] booster instead of launching a spacecraft.  Compare to air launch, which trades large mass (and volume, and often the ability to "top up" lox or lh2)  requirements to allow a much larger bell and less air resistance while launching.  Two companies have successfully done air launch (Orbital and Virgin Orbital.  Did a MiG ever launch something into orbit or simply demonstrated anti-satellite capability?), but nobody has gotten close to cannon launch.

I still like the idea of launching a SCRAMJET with a railgun.  Not that the tech is remotely ready, but NASA *did* demonstrate a working SCRAMJET already, and the rail accelerators are even used to launch roller-coasters

Not arguing with you, I think a cannon launch to orbit is unlikely as well. I just thought it was funny that nobody had mentioned the most serious efforts in the field to date.

[kerbiloid]

A cannon as high as a space lift.

[Shpaget]

8 hours ago, kerbiloid said:

A cannon as high as a space lift.

If inspired by Stg 44 Krummlauf, no need for orbital insertion burn.

[Spica]

On 11/6/2021 at 8:40 PM, Lisias said:

In fact, the Germans had developed a kind of cannon where the projectile was kicked out from the huge barrel by a series os smaller explosions, each one adding up from the last. Pretty interesting, pretty impressive, and this idea can be useful on our thesis:

Unfortunately this trick doesn't actually let you gain significant speed beyond what you'd get from a normal gun.

Once the projectile reaches speeds close to the practical limit of a single chambered gun, any additional chambers provide little if any further velocity increase.

Think of it like this: before the gas from the additional chambers can push on the projectile it must first catch up with the projectile. Once it has accelerated to match the speed of the base of the projectile little energy remains to continue to accelerate the projectile along.

A more technical description is found here: https://www.researchgate.net/publication/268456817_A_comparison_of_distributed_injection_hypervelocity_accelerators

There are other tricks that can work though, which are described in more detail in the paper I linked here. One of which involved injecting gas perpendicular to the barrel and expanding it along a tapered projectile.

Edited November 8, 2021 by Spica
expansion