But they are right that we don't have the ability to make enough helium to make that make sense. I can believe that hydrogen can be made to work. But when they got to making the frame out of magnesium - a leak in the rain would be scary!
This is one of those ideas that seems better in theory than practice. Not as bad as the fact that adding mercury to rocket fuel makes it go better. But still not a great thing to do.
For those who are puzzled at the mercury comment, energy is proportional to mv^2/2 while momentum is mv. Mercury takes away a bit from the energy, but increases the density, and therefore gives you more momentum per unit of fuel. It is a great theory, ruined by the fact that we'd be spraying nasty poisons everywhere.
I don't understand this. LH2/LOX typically burns on the rich side to increase exhaust velocity. This means more momentum for less mass, which is what you want from a rocket. This is the opposite.
But they are right that we don't have the ability to make enough helium to make that make sense. I can believe that hydrogen can be made to work. But when they got to making the frame out of magnesium - a leak in the rain would be scary!
This is one of those ideas that seems better in theory than practice. Not as bad as the fact that adding mercury to rocket fuel makes it go better. But still not a great thing to do.
For those who are puzzled at the mercury comment, energy is proportional to mv^2/2 while momentum is mv. Mercury takes away a bit from the energy, but increases the density, and therefore gives you more momentum per unit of fuel. It is a great theory, ruined by the fact that we'd be spraying nasty poisons everywhere.