Evel Knievel in spaaaaaace!

So, Bob Truax of Sea Dragon fame worked with Evel Knievel for a time. He built Knievel's rocket-powered "Skycycle" and was even building a sub-orbital rocket out of parts obtained from scrapyards that would have made Knievel the first private person to reach space. Knievel pulled out of the project though, and it folded for lack of money. What if Knievel didn't pull out though? And what if the rocket worked? What happens if a backyard rocket manages to reach space and return its pilot to the ground by the early '80s?

fasquardon
 
The chance of the rocket working are the same as finding snow pigs flying through hell... Knievel had a bit of a shock when he saw the insides of the "Skycycle", nearly pulled out of that project, i'd imagine his reaction to the space rocket would be a declaration that even he's not that crazy.
 
What Knievel needed is rocket that only get to speed mach 3~4, after separation of the Booster, the capsule swing just over 100 km mark.
With those speed the capsule not even need a heat shield like Mercury capsule.
equipped with Parachute and airbags for Capsule and reserve parachute for Knievel provide save landing.

in size the rocket would be V2 or like Canadian Arrow (defunct)
640px-Canadian_Arrow.jpg
 
Imagine his legend now if Knievel made it into space but then both the rocket and he himself disappeared never to be heard from again.
 

Bull was designing his space-cannon as a satellite launcher, but boy! Writing the alternate history of a Truax-Bull team would be awesome...

Maybe they team up building hybrid cannon-rocket launchers that used the cannon as the "first stage", and surplus ICBMs as the second stage? It sounds nuts, but I am fairly sure the engineering would work... I'm less sure the economics would work though, probably would be too complex.

fasquardon
 
Maybe they team up building hybrid cannon-rocket launchers that used the cannon as the "first stage", and surplus ICBMs as the second stage? It sounds nuts, but I am fairly sure the engineering would work...

You could probably make something that would work, but I very much doubt you'd be using surplus ICBMs as the second stage. Per the link provided by Konrad Sartorius, a Sprint missile had a maximum acceleration of 100g - probably much higher than any ICBM was built to do. By contrast, the space-cannon is listed as imparting an acceleration of 1800g during a fairly "soft" launch. I can see no reason why ICBMs would be built to survive that sort of stress, so you'd basically have to build the second stage from scratch. As you say, the economics probably wouldn't work out.
 
You could probably make something that would work, but I very much doubt you'd be using surplus ICBMs as the second stage. Per the link provided by Konrad Sartorius, a Sprint missile had a maximum acceleration of 100g - probably much higher than any ICBM was built to do. By contrast, the space-cannon is listed as imparting an acceleration of 1800g during a fairly "soft" launch. I can see no reason why ICBMs would be built to survive that sort of stress, so you'd basically have to build the second stage from scratch. As you say, the economics probably wouldn't work out.

The acceleration depends on the power of the explosive charge and the mass of the missile. Think of the Orion with its nuclear pulse engine - I guarantee, if you used a nuclear bomb to propel too small a craft, it would experience g forces far beyond those experienced by a rifle bullet. But with something as large as an Orion, each bomb's energy is absorbed by enough mass that the change in velocity is such that the human body isn't atomized by it.

It's just a matter of sizing the parts correctly.

fasquardon
 
The acceleration depends on the power of the explosive charge and the mass of the missile. Think of the Orion with its nuclear pulse engine - I guarantee, if you used a nuclear bomb to propel too small a craft, it would experience g forces far beyond those experienced by a rifle bullet. But with something as large as an Orion, each bomb's energy is absorbed by enough mass that the change in velocity is such that the human body isn't atomized by it.

It's just a matter of sizing the parts correctly.

fasquardon

"Just". In this case I think the devil is in the details. What you say is correct as far as it goes, but that acceleration has to end up with the missile moving at a useful velocity. Otherwise, why are we bothering with the gun at all? And that velocity has to be achieved within a relatively short linear distance (the length of the gun barrel). I'm sure it is possible to build a gun that accelerates an ICBM gently enough for it to survive the process, I am NOT sure it would be possible to do so in any reasonable length (less than, say, a few kilometres).

Total delta-v requirements for LEO are about 10km/s. The gun has to provide a decent proportion of that or there's no point in using it. An ICBM might be able to provide 7km/s, which means the gun has to provide 3km/s. The Quicklaunch system Konrad provides a link to specifies a 1.1km barrel and a muzzle velocity of 6km/s, which gives their 1800g acceleration figure. Note that even at best they were only hoping for a 450kg projectile, some of which would have been the orbital circularisation motor. A Minuteman missile weighs a good deal more - 35 tonnes, in fact. My maths and physics knowledge is not up to the task, but I'm sure someone more knowledgeable could work out what sort of acceleration is necessary to get that up to around 3km/s.

Long story short, I don't think you're going to be using stock ICBMs for this.

*Edit*

I'm not sure what acceleration an ICBM is built to withstand - probably less than 10g, but for the sake of this exercise let's assume it's the same as a Sprint missile (100g). Having used this site as a calculator, and assuming constant acceleration from 0m/s to 3000m/s, we're looking at about 450g of acceleration over a 1km barrel length. Our hypothetical ICBM second stage won't survive that. If we want to keep it to 100g then we need a barrel more than 4.5km long.

All of this assumes acceleration would be constant, which it wouldn't be. It would either come as a single shock at the start, or in several jolts as subsidiary charges fire while the projectile moves up the barrel (the V3 design). I doubt ICBMs could be used without modifications so extensive you might as well just build a complete new upper stage.
 
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To clean the Mess up
The Cannon launch not gonna work do to extrem acceleration of 1800 G, only one human survive acceleration 214 G for millisecond during race accident
This has to to do with distance the acceleration happens, for gun around 10 meter or 33 ft. what let to high g force of 1800 up to 10000 G !
A clever man (i not recall his name) calculated who long a gun must be to launch human save, he came to staggering 430 km or 267 miles long tube !
That's beyond the capacity of Knievel organization
by the way
the Orion atomic bomb engine acceleration is at 2 G for ground launch do longer distance it has to gain orbital speed...

ICBM
there is allot abandon hardware in 1970s
like Atlas or Titan I ICBM or Redstone and surplus mercury hardware lounging around
question can Knievel organization get there hand on it ?
can they refurbish it and have they money for it ?
Grand NASA logistic or launch site for Knievel flight ?
 
A clever man (i not recall his name) calculated who long a gun must be to launch human save, he came to staggering 430 km or 267 miles long tube !
That's beyond the capacity of Knievel organization

So definitely not economically feasible...

Grand NASA logistic or launch site for Knievel flight ?

It would be fun to see the missile launched from a sufficiently deep lake or harbour...

I think the plan was just to build their own rudimentary launch pad (I wonder if there were any abandoned military surplus silos on the market in the 70s - could make a good launch pad).

fasquardon
 
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