Comment Hydrogen would work, but would not be safer (Score 1) 701
Hydrogen could propel an aircraft of that size, but only if it were stored in liquid form (highly compressed or extremely cold, and compression is much less expensive than cryo tanks). The space shuttle is powered by hydrogen powered engines, and the reaction is the simplest chemical reaction:
2H2 + O2 => 2H20
If the tanks were to leak, and sealing at these pressures is difficult, the leaking hydrogen would immediately vaporize (i.e. dry) and would be very volatile. Any rupture to the atmosphere coupled with any source of heat significant to cause combustion would cause a reaction exactly like the space shuttle Challenger we all saw in the 80's.
2H2 + O2 => 2H20
If the tanks were to leak, and sealing at these pressures is difficult, the leaking hydrogen would immediately vaporize (i.e. dry) and would be very volatile. Any rupture to the atmosphere coupled with any source of heat significant to cause combustion would cause a reaction exactly like the space shuttle Challenger we all saw in the 80's.
