It has been proposed that we could construct one of these nuclear potato guns to launch things into space[1]. One digs a multi-kilometer deep borehole in say a

It has been proposed that we could construct one of these nuclear potato guns to launch things into space[1]. One digs a multi-kilometer deep borehole in say a salt dome(easy to drill), lines that with steel, puts a bomb at the bottom, some reaction mass(essentially trash that will vaporize in the explosion), and a projectile we wish to launch into space. So this solves several problems over other nuclear bomb based propulsion methods like Project Orion[0]. Foremost, we can contain almost all of the fallout. Second, we aren't accidentally triggering nuclear war by lobbing a bunch of nuclear bombs into orbit. In addition, if the nuclear charge is 150 kilotons or less and that charge is detonated underground then it's in full compliance with certain treaties. So aside from the shear political impalatibility of using nuclear bombs, there are a couple problems. Namely, even if we use a very long shaft, the acceleration is still on the order of thousands of Gs. So no launching humans. Second, it's impossible to get into earth orbit purely with a cannon launch. And because it's difficult to make stuff that can withstand thousands of Gs of acceleration, orbital circularization will be difficult. So one suggested use case is to literally shoot the moon. One fills the projectile with things that can withstand the high acceleration like water, construction materials, MREs, propellant, and carbon(extremely rare on the moon, but extremely useful for refining silicon for solar cells). We launch this projectile, which should mass ~3000 tons or so, to the Moon and then harvest everything we need to bootstrap a Moon base from the impact site. Perhaps we can even save money on our MREs by letting the acceleration do the food processing. For example, for apple sauce, all we need to is put cored apples in a plastic bag. The thousand G acceleration of the launch and lunar impact should be more than enough to reduce them to pulp. Now, while we can't get into Earth orbit easily, if the projectile velocity is sufficiently high we can put the projectile into solar orbit. It is a questionable proposal, but interesting nonetheless. [0]https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion) https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls... [1]https://www.nextbigfuture.com/2010/03/150-kiloton-nuclear-verne-gun.html https://www.nextbigfuture.com/2010/03/150-kiloton-nuclear-ve... [2]https://www.nextbigfuture.com/2010/12/sea-based-launch-option-for-nuclear.html https://www.nextbigfuture.com/2010/12/sea-based-launch-optio...