the verne gun

[MacJeb]

I have seen and tried the orion propulsion mod, but it seems too overpowered and lethal{radiation} form of propulsion..

but thanks to atomic rockets website I found out about the verne gun:

"You set off one solitary ten megaton nuclear device in a deep underground salt dome.

Perched on top is an Orion type spacecraft. All the EMP and radiation is contained in the underground cave

(as has been done with historical underground nuclear tests). And 280,000 TONS of payload sails into low Earth orbit."

it seems like a pretty interesting and reasonable method of launching heavy stuff into space,

of course the draw back that the mission would have to go unmanned,

maybe modify the orion addon to this? what you think

[Van Disaster]

Presumably most of the 280kilotons is heat shield...

You have an interesting definition of "reasonable"

[Guest]

Create a tiny, temporary sun to propel your payload to orbit. Yep, that's my kind of reasonable!

[MacJeb]

well I am no scientist but the idea just caught me though I did not do any calculations or things .. it could be more reasonable than orion boom boom boom --. at least I think :}

Edited September 26, 2013 by MacJeb
switchword

[Kerbart]

Scott Manley did some math on it, but let's see...

Delta-V for low-orbit is around 9500 m/s. Let's assume that we build a launcher with a 30km gun "barrel" and we have linear acceleration. Speed when leaving the gun: 9500 m/s.

Speed is acceleration × time: v = a*t = 9,000 (1)

Distance travelled in barrel is s = ½ * a * t² = 30,000 (2)

Substituting (1) into (2) gives us : ½ * v * t = 30,000 ==> ½t = 30000 / 9000 ==> t=6.3s

So, to get into orbit we need to leave our 30km barrel at 9500m/s, and we'll get there in 6.3s Take a minute to let this sink in: 20 miles in 6.3s from stand still. That's about 1428 m/s² or 145g.

Reasonable?

Of course you can tweak the numbers. Longer barrel, those kind of things. And lets say that you manage, eventually, to get down to "only 15g". Keep in mind that it takes well-trained jet-fighter pilots years to master the art of not passing out around 9 g for a few seconds, and that 15g will have to be maintained for around a minute-and-a-half.

The gun would work for inanimate objects (say, manhole covers) but it's not likely it can ever be used for breathing humans.

Edit Oh, and we're bypassing trivialities like doing mach 27 at sea level and all the heating problems it brings...

Edited September 26, 2013 by Kerbart
whoops

[Kulebron]

Even for Moon, such a railgun would be quite big: 100 kms to get into orbit (2600 m/s) with "only" 5g acceleration.

[Kulebron]

EditOh, and we're bypassing trivialities like doing mach 27 at sea level and all the heating problems it brings...

Heard a version of it: in Antarctic, pour a mountain for some of it's distance, evacuate air and close it's top with some soft cover (at 10 or 20 km of height, the pressure will be low to not break it). When the gun will fire, it will accumulate the residual air ahead of the projectile and this will throw away the cover (or it should be just soft and easily breakable).

[jwenting]

and of course you need to go faster than that, because by the time you leave that barrel you're going to have to travel through several hundred miles of atmosphere without propulsion (where the drag will seriously slows you down) and you want to end up in orbit at 9500m/s.

Don't have the drag calculations (which could get nasty, body slowing down while the drag coefficient goes down as well, both in non-linear fashion over time and influencing each other), but let's assume that adds another third to the needed muzzle velocity (and more than likely that's overly optimistic).

[lajoswinkler]

... and nothing would ever come out of the cannon. Yeah, right.

Ten megaton underground and you've got yourself a series of earthquakes around the planet, possibly killing tens or hundreds of thousands of people, and the cannon spits out a geyser of boiling quicklime contaminated with einsteinium, fermium and other scary elements into the stratosphere.

Highly reasonable.

[Kerbart]

and of course you need to go faster than that, because by the time you leave that barrel you're going to have to travel through several hundred miles of atmosphere without propulsion (where the drag will seriously slows you down) and you want to end up in orbit at 9500m/s.

Don't have the drag calculations (which could get nasty, body slowing down while the drag coefficient goes down as well, both in non-linear fashion over time and influencing each other), but let's assume that adds another third to the needed muzzle velocity (and more than likely that's overly optimistic).

Doing some quick on-the-back-of-a-napkin calculations...

Leaving on a tangential course (parallel to surface) on a 6000km radius earth, you'd have to travel (in a straight line) 1100 km to reach 100km altitude, and of that 1100km you'd spend more than half (600.74km to be less inaccurate) below 30km where we have a fairly thick atmosphere.

So that'd be 63 seconds up to 30km height

And another 52 seconds from there to 100km height.

Somehow i thought it'd be quicker and didn't think the effect would be that severe (it's time exposed to air resistance that determines how much you bleed in speed, not distance travelled) but spending nearly two minutes in the atmosphere, and more than a minute in the thicker part... yikes!

[Kerbart]

... and nothing would ever come out of the cannon. Yeah, right.

Ten megaton underground and you've got yourself a series of earthquakes around the planet, possibly killing tens or hundreds of thousands of people, and the cannon spits out a geyser of boiling quicklime contaminated with einsteinium, fermium and other scary elements into the stratosphere.

Highly reasonable.

In all fairness, the OP did say he didn't do the calculations.

And you do make it sound like an awesome plan!!

[BostLabs]

Ow! Not again!

[Halsfury]

As a matter of fact this method was used for an accidental deep space launch

During operation Plumbob in the early 50's a nuclear physicist managed to miscalculate the power of a nuclear device in an underground test, on top of the bomb was a long concrete tunnel with a concrete plug in it, at the very top of the shaft was a large blast cover weighing about 4 tons.

The ensuing explosion was several orders of magnitude larger than planned and managed to turn the concrete plug into ionized gas & lava, the blast cover was reported to have been launched in excess of 70km/s, beating the Helios 2 probe which is supposedly the fastest man made object.

http://losthunderlads.com/2013/03/07/the-worlds-fastest-manhole-cover/

Though many think that the atmosphere would have slowed down the manhole cover such that it did not escape earth's gravity, the Blast cover probably became molten confetti in the atmosphere, but, a small chunk/chunks could have reached space since the atmosphere would have given the confetti an aerodynamic teardrop shape like rain, but going the other way.

There is probably an alien still trying to figure out whether his insurance covers him from atomic shotguns firing hot radioactive debris:)

[MacJeb]

haha interesting thinking with the einsteinium element and stuff.. but I also never said there would be a man sitting in that "soon-to-melt" vessel, so noo need to worry about some gs I don't know though how much of an earthquake it would make

[wasmic]

Well, since this is Kerbal space program, and delta-v for kerbin orbit is as low as 4000 m/s, I think you're being a bit pessimistic. Well, ofr real life, it would be supid, but for KSP, it would be very jeb-magnetic.

EDIT: @Halsfury: Ha, didn't know about that. It sounds completely nuts... ubt then again, things tendd to go nuts when nuclear scientists are about.

Edited September 26, 2013 by wasmic

[MacJeb]

yeah in fact I proposed this as a possible alternative to the great orion mod

also

"There is probably an alien still trying to figure out whether his insurance covers him from atomic shotguns firing hot radioactive debris"

[lajoswinkler]

The impulse wouldn't actually cause global earthquakes, the energy is simply too low for that, but it could trigger release of tectonic tension that's built up around Earth in some areas. Local earthquake would be, well... disastrous. Some of you might've seen the footage from one of such tests with much lower yields, where the camera is in the actual blast zone. In few seconds there's no more ground to speak of. It turns into a mixture of air and dirt who knows how deep. Ground waves can be seen and the structures are thrown around like toys.

10 MT would be absolutely disastrous. Nuclear bombs work best when surrounded by medium. If you fire them in vacuum, the push is pathetic compared to the damage in the atmosphere or underground.

Fortunatelly, such tests have ceased and there's lot of equipment measuring tremors around the planet. Even when North Korea tried to blast their firecracker which fizzled, it was promptly detected and characterized as possible conventional chemical detonation in order to scare everyone around.

[Technical Ben]

As a matter of fact this method was used for an accidental deep space launch

During operation Plumbob in the early 50's a nuclear physicist managed to miscalculate the power of a nuclear device in an underground test, on top of the bomb was a long concrete tunnel with a concrete plug in it, at the very top of the shaft was a large blast cover weighing about 4 tons.

The ensuing explosion was several orders of magnitude larger than planned and managed to turn the concrete plug into ionized gas & lava, the blast cover was reported to have been launched in excess of 70km/s, beating the Helios 2 probe which is supposedly the fastest man made object.

http://losthunderlads.com/2013/03/07/the-worlds-fastest-manhole-cover/

Though many think that the atmosphere would have slowed down the manhole cover such that it did not escape earth's gravity, the Blast cover probably became molten confetti in the atmosphere, but, a small chunk/chunks could have reached space since the atmosphere would have given the confetti an aerodynamic teardrop shape like rain, but going the other way.

There is probably an alien still trying to figure out whether his insurance covers him from atomic shotguns firing hot radioactive debris:)

Wait. That story has one vital floor... rain does not fall in teardrops!

[Halsfury]

Wait. That story has one vital floor... rain does not fall in teardrops!

you're kidding me right? It matters at 6 times escape velocity in atmosphere?

[Captain Sierra]

you're kidding me right? It matters at 6 times escape velocity in atmosphere?

It absolutely matters. Shape is EVERYTHING at those speeds. Wrong shape and you either disintegrate or slow very fast.

[The Destroyer]

Guys,

This is KSP,

Why NOT have a gigantic unreasonable cannon! It would be fun!

I mean, my laythe counter-orbiting manned vessels suffer 100 gs on re-entry, these are kerbals, not flimsy humans!

[Captain Sierra]

And this is what they look like after said 100+ G reentry.

[Raticon]

... and nothing would ever come out of the cannon. Yeah, right.

Ten megaton underground and you've got yourself a series of earthquakes around the planet, possibly killing tens or hundreds of thousands of people, and the cannon spits out a geyser of boiling quicklime contaminated with einsteinium, fermium and other scary elements into the stratosphere.

Highly reasonable.

It is reasonable for the cause of SCIENCE!

Really, as far as Kerbal Space program this would be quite fun and interesting, but in our world, no... But KSP is not our world so let's get blasting! :D

[Halsfury]

It absolutely matters. Shape is EVERYTHING at those speeds. Wrong shape and you either disintegrate or slow very fast.

Well the blast cover was probably the wrong shape so it disintegrated, but to all intents and purposes, at these speeds "disintegrated" really means "exploded violently"

Even the slightest pocket of air in the steel blast cap would expand and burst, because of this I am willing to suppose that this additional impulse is capable of acting as a high altitude second stage.

[Guest]

You have to admit, whether you're setting off one big nuclear blast or pooting out lots of little nuclear explosions just to try and get somewhere, it's all pretty daft. Way too messy, especially for anyone left in your wake.