So how do you keep it from bursting? Or would reading about ballasthalo explain that?
I wonder what the actual formula is to calculate the correct balloon size? It seems like it might be some complicated differential equation. Here's why:
Say I want to lift 10 lbs. So I figure out I need X volume of helium. So I need a balloon weighing 1 lb to hold the helium. Now I need a balloon big enough to lift 11 lbs instead of 10, repeat, repeat.
If by “complicated differential equation” you mean either “surface area is approximately proportional to radius squared so this could be solved by 8th graders” or “just add 20% margin and it’ll probably work perfectly well”.
We’re talking about a balloon that we want to have rise to the stratosphere in 2-3 hours. If the balloon rises at 4 meters/second, or 7, instead of 5, it’s really not the end of the world. Just pick a size, calculate (rather trivially) how fast it’s going to rise, and then change the amount up or down.
If it really must be exactly 5 meters/second (or whatever), the computation is still at about the level of a slightly-above-average 8th grader.
A 20% margin would reduce space-access costs immensely.
We use exotic alloys, explosive fuels and precision machining because we need to reduce weight to the structural limits. If we hadn't, space access would be cheaper and safer.
Sadly, Earth has just enough gravity to ruin our day.
I wonder what the actual formula is to calculate the correct balloon size? It seems like it might be some complicated differential equation. Here's why:
Say I want to lift 10 lbs. So I figure out I need X volume of helium. So I need a balloon weighing 1 lb to hold the helium. Now I need a balloon big enough to lift 11 lbs instead of 10, repeat, repeat.