If there was a way to use the hydrogen as fuel or compressing it down afterwards so it would sink instead of rise.
There are several problems with compressing it, but if the rocket's initial thrust could e used to power a change of state compressor(or whatever)......and how much energy would that take anyway?
dA = p(V)*dV
Assuming you're compressing it slowly, so heat gets lost...
p(V) = p1*V1/V
dA = p*V/V'*dV
A = P*V*Integral(1/V'*dv)
A = p*V*Log(V/V2)
V is the initial volume, V2 is the compressed volume.
The initial volume can be calculated easily:
Fg = Fb (Buoyancy)
m*g = V*Rho-V*Rho' (Rho is density of air, Rho' is density of hydrogen)
m*g = V*(Rho-Rho')
V = m*g/(Rho-Rho')
I'm not gonna write out the equation to calculate the density of air and hydrogen at high altitude, because I don't have good data for how temperature changes with altitude...
The question is, how much do you want to compress the balloon? To the point where it can't carry the rocket anymore and the whole thing starts to fall?
To the point where after the rocket's release, the balloon still falls?
tylor2000 said:
If you constructed the balloon a certain way so that it was meant to exploded but in the opposite direction of the rocket's intended vector in some preplanned orientation then it might actually be used to give extra energy to the rocket. We could call that stage 0, or -1.
Even if you could get a big enough balloon that would really explode under pressure and not just burst and leak gas, the explosion would never be violent enough to push the rocket anywhere.
tylor2000 said:
We could construct the balloon to be at least partially surrounding the rocket so when the rocket fires the initial acceleration could be used to condense the gas or to orientate the balloon so it explodes behind the rocket. For every force there is an equal and opposite force, ect,
and so goes the possibilities......
If the rocket was inside the balloon and fired it's engines, the balloon would get torn to shreds and leak out with a gentle wizz.
If you put a lot of pressure inside of a non-stretchable balloon, you will increase the density inside it and make it heavier. The balloon would lose the ability to lift weight.
p*V=m/M*R*T
p=m/(V*M)*R*T
m/V = Rho
p=Rho/M*R*T
Rho = p*M/(R*T)
As you can ses from the equation, if the pressure rises, density rises.