Buoyancy Spaceship

>build spaceship, optimize it's aerodynamic profile while maximizing volume (I imagine something very long and slender)
>fill it with air for breathing and buoyancy
>transport it out to sea, preferably somewhere as deep as possible (like the mariana trench)
>attach a sufficiently heavy weight (like a huge fucking rock or something) by straps/chains/whatever
>drop it into the sea, let it sink to the bottom of the ocean (roughly 11000m)
>disconnect the straps/chains securing it to the rock
>because of buoyancy the ship accelerates upwards
>it shoots off into space
>basically imagine pushing a soccerball or something similar underwater when you're in a pool and let the ball float upwards, shooting out of the water

I mean why the fuck not

I don't have the patience or the time to give all the reasons why this would be extremely dumb.

Nor the knowledge obviously

[math]
F = \rho g \Delta V - \frac{1}{2} \rho A v^2 C_d
[/math]
You'd reach a terminal velocity pretty quick, because the density of seawater is enormous. This is a faulty model, but only slightly since the density variations are relatively insignificant. Additionally, you'd have to continuously vary pressure inside the vessel to ensure it doesn't explode; this is feasible, but would probably not end up being very efficient.

Also I pretty much guarantee you that the values you'd get for terminal velocity are way lower than the required velocity to reach LEO.

I actually think this is a good idea but I think it would be impossible to build something both bouyant enough and strong enough. Also I'm not sure ocean is deep enough.

How do we make sure it stays facing upright?

I don't know the physics that well but it may not even be possible in principle, it may be impossible to accelerate any object to escape velocity in this manner.

This is probably bait, but there's no way you're an engineer.

Maximise volume, fill with air to make light. Crushing pressure underwater which increases with depth, which therefore requires reinforcement. You have two very much opposed design criteria. It might be possible to make something that shoots up, but toward space? No way.

You're right, I'm not an engineer. I'm just a regular schmuck without a "job" or studies (I earn all my money passively) so I have a lot of time on my hands for thinking about shit like this.

Brainlet answer
Good answer

The number one thing that's actually wrong about it isn't something like muh design but the simple fact that water is really dense and you want something to go really fast in it. Look at how water affects bullet ballistics.

IF we were to remove the actual water resistance it could be not an entirely bad idea to store energy as potential buoyancy, pretty much free propellant. Too bad though.

>drop it into the sea, let it sink to the bottom of the ocean (roughly 11000m)
the ultra high pressures down there would crush your vessel

>>because of buoyancy the ship accelerates upwards
yeah, but it rises pretty slowly in super high pressure water. friction and all that.

>>it shoots off into space
no

They could release air bubbles just ahead of the rocket so that the terminal velocity of the water would be lowered a great deal. The water will push it up even faster than normal. It is the same principle to sink a ship. Air bubbles come up and make the boat less buoyant. Only this is above the rocket.

Wait!!!

Make a tube that goes from the surface to the sea floor. Evacuate the tube of water, stick the rocket in it on a buoyant platform. Flood the tube from the bottom, under the platform. The platform rises and shoots the rocket out of the tube. All the infrastructure needed to keep the water pressure out will be the tube instead of the rock.

that's actually pretty smart god damn

this wouldn't work on buoyancy, your idea (if I understand it correctly) is just water pressure pushing this "rocket" from bellow
it's essentially a squirt gun, it uses pressurized liquid as propellant instead of expanding gasses like normal guns
many people tested the space gun concept and it's just not as practical as rockets

I'm not sure we could build an undersea chimney stack 8km+ tall/deep to begin with

>I'm not sure we could build an undersea chimney stack 8km+ tall/deep to begin with

It would be difficult but it's rocket science so...

>a crack breaches the tube because maintaining an 8km+ infrastructure under extreme amounts of pressure is very difficult
>nobody wants to go near the crack because they will be sucked to/through it


That's just one scenario. Obviously it could be fixed with advanced AI monitoring systems and replacing humans with robotics for maintanence.

But what about empited the tub of water after each launch? Now that I think about it, how the hell does this thing even get built in the first place?

>it's essentially a squirt gun
>world's biggest squirt gun
Hah fuck you aliens

You build the entire structure underwater without air spaces. Just simply RVs and welders, etc. You only every remove the water from inside when it is finished and only when you want to launch. Once a launch is complete you fill it with water. That way it only experiences pressure during a launch.

>Mariana trench water pressure 15,750 psi/108,592,427 square meter Newtons.
>Falcon 9 Full Thrust( Falcon 9 v1.2) Initial thrust: 7,607,000N

Too bad the psi lowers so much the higher you get in the water column.

How do you feel that all your times spent thinking is useless? Since your knowledge is limited your reasoning is flawed and your theories are shit.

Seems like a pretty fun deal for him to me, and you seem butthurt lmao

>yet another deep example of irony posted to Veeky Forums

>all your times spent thinking is useless?

That's just, your opinion.