[SSN558]

"His comments are written to falsely that imply hydrogen is not efficent as a fuel."

Hydrogen is not a very efficient fuel. My text books are at work or I would quote exact values, but Hydrogens heating value per pound is just fractions of that for hydrocarbon fuels. So the tanks have to be rather large. That is the reason for that rusty abortion you see attached to every space shuttle. Use of hydrogen in the vapor phase would employ even larger tanks, proportionally.

[tallhappy]

but Hydrogens heating value per pound is just fractions of that for hydrocarbon fuels. So the tanks have to be rather large. That is the reason for that rusty abortion you see attached to every space shuttle.

Why don't they use hydrocarbon fuels for the shuttle?