Space Guns Don't Work (But We Built One Anyway)

Before we had rockets like the Falcon 9, we had other ideas of how we might shoot for the moon: space guns!

Hosted by: Reid Reimers

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[anobscurereference]

You know, I do find the absence of my skeleton to be a slight inconvenience.

[danheidel]

It's too bad you didn't mention the fascinating and tragic story of Richard Bull, the prime person behind HARP. After HARP and SHARP were canceled, he went on to try and find funding for his projects to continue them. He ended up going to Iraq where Saddam Hussein was willing to fund an orbital super gun in exchange for Bull designing better artillery systems. The project was fully underway when Bull suddenly got a case of being shot 4 times in the face, presumably from the Mossad who weren't too keen on Saddam having artillery that could hit Israel.

[capnseriousnap]

I have the solution, we just need a space gun, that fires other smaller space guns until we reach orbit :v

[chfkmm]

Had to think of THGTTG: "There is an art to flying, or rather a knack. The knack lies in learning how to throw yourself at the ground and miss."

[themexis]

Greetings from Barbados, SciShow. Thanks for the mention. I think a guy named Gerald Bull and some Canadians were involved with that H.A.R.P. thing too.

[BooBaddyBig]

Pedant point: rockets are ballistic, the term ballistic means you lack aerodynamic lift. Rocket science is studied as part of interior ballistics.

[Merennulli]

There is actually one in development now using an enormous low pressure enclosure where it spins up to high rotational velocity with a counterweight, then releases through an insanely fast airlock. It's not relying solely on ballistics of course, just flinging capsules into space where they can shed the protective sabot and then do whatever they need to do, including propelling into an orbit.

It's high up-front cost but pays off by cheaper small satellite launch costs and a higher repeat rate than rockets. Assuming no surprises scaling up to full size.

[AlexADumbDumb]

You overlooked the biggest advantage of space guns - they don't require propellant or explosives. A sufficiently-long railgun would be able to launch projectiles into space, needing mainly just electricity, which could be provided by renewable means. It wouldn't be able to send people (at least not without a SUPER long barrel to accelerate more slowly), but it could send specially designed electronics or other equipment into orbit. It would be useful to send, for example, raw materials for use in in-orbit construction, or autonomous probes, satellites, etc.

[sween]

that one time they launched a 'man hole cover' using a nuke, never found it was only captured on high speed camera in one frame.

[bluewhaleking]

Another big problem is air resistance. Not only does it cause enormous drag at those speeds, but the friction will burn up the payload if you have it going fast enough to reach higher than just the edge of space.

[anomamos]

Space guns are actually a very viable way to launch bulk materials into space.
The issues that need to be considered are the initial acceleration forces and the shock of hitting the air when leaving the muzzle and the friction during acceleration.
Having the muzzle high up the side of a mountain so it is in the thinnest air can reduce the shock of hitting the atmosphere starting the payload off slowly and building speed until it just needs a push instead of a kick will reduce the massive initial G forces to a survivable minimum and using maglev in a vacuum will reduce friction so all you need now is a cool name like hyperloop or something.

[MrHwsmp]

There are ways around two of those problems:

1. You can get around the high acceleration problem by smoothing out the impulse on the projectile by accelerating it along the entire length of the barrel, rather than just at the start. One was of doing this is to have auxiliary breeches located along the barrel that fire their propellant charges after the projectile has passed them. The projectile thus gets a series of small pushes rather than one giant one. The Germans actually built a prototype of this system in WWII. Another way is to replace solid propellant by liquids or gases pumped into the chamber at a measured rate from the moment the projectile launches until the moment it leaves the barrel. It thus gets a continuous measured acceleration, more akin to a rocket: in fact, you could think of it as leaving your rocket motor attached to the ground and using it's exhaust to push you up the barrel.

2. The inability of the projectile to circularise it's orbit can be solved by simply giving it a rocket motor that it fires at apogee. If you look at a normal space rocket, the vast majority of it's size and mass is accounted for by the stages that get it into space, i.e the same job that's being done by the space gun. The stage that circularizes it's orbit is relatively small.

Of course, none of this changes the fact that a space gun capable of firing a useful payload is going to be very big and very expensive to build, even if it's cheaper to operate in the long run. Even the fact that modern electronics make it possible to do useful things with tiny cube sats doesn't change this much, because their small size means that cube sats can be just as easily piggy-backed on a conventional rocket launch, thus getting their ride into space for nearly-free. One reason for building a space gun might be that a country didn't have a suitably safe downrange area to their east in which to drop spent rocket stages, such as an ocean (USA) or a wilderness (Russia). As long as the space gun's ballistic 'target area' was clear, it would present no danger to people under the flight path of the launch even if the apogee motor failed to fire.

[Robb]

Rail guns hold a lot of potential because they can be used for sending raw materials like metal billets into space. The metal can be shaped into hypersonic projectiles and hardened on the outside or coated with ceramic to tolerate the heat of friction and than shot up to an orbiting capture device rather than trying put them directly into orbit. The materials would then be used for manufacturing building materials in space where even solar energy could be focused to make a blast furnace. An efficient system could even take advantage of frictional heating since the material would arrive nearly hot enough to vacuum cast and would stay hot for quite some time in the vacuum.

[joecope]

In 1992 Marshall Savage proposed a long space gun he named "Bifrost" that involved an underground tunnel that traveled up the side of an equatorial mountain and launched a type of airship called a "waverider". On the back of the waverider would be a large block of dry ice that would be shot with pulses from a ground-based laser to continue to propel it after it had left the space gun.

[gzfeqpvtrspdd]

I thought this video was about guns that can shoot in space.
But still interesting

[Kari-tufs]

The interesting thing here, is that in hard vacuum, they become somewhat viable, because you suddenly lack the drag from an atmosphere you only have to exceed the gravity of whatever you are firing from.

So, for example. you could build a bigass gun on the far side of the moon and use it to launch stuff deeper into space, hell you could even have the payload being propelled with a solid fuel rocket inside the barrel so it has constant acceleration through the entire length of the barrel, this would also give you a high pressure zone behind the payload and increase the acceleration.

[Jobobn]

The new hair style is on point, man! Looks good!

[greypaladin]

As someone who plays too much Kerbal, you can shoot something into orbit. Just, you need to shoot it so that it interacts with another body and is nudged into an Earth orbit. So, kind of a "Shoot for the moon, and even if you miss you'll get nudged into a stable Earth orbit, which is what you wanted anyway."

Oh, and please look up a Launch loop (and check out Isaac Arthur's videos on it), it's sort of a gun, sort of a train, either way it's at the edge of space and makes SpaeX look like an expensive toy.

[TheMattastic]

"Pfft! Who needs science!?" —SciShow

[dhawthorne]

building and firing one IN space would be an interesting idea. The barrel could have several projects mounted to it for additional mass and would collect data as it drifted off in the opposite direction of the projectile. That projectile may even be able to reduce the time for interplanetary trips (for inanimate payloads).