As briefly mentioned in the previous answer, H2 is very tricky to deal with. The temperature is one thing, but what he didn't mention was its extremely low density. If I recall correctly the LH2 tanks on the shuttle require around 4-5 times the space of its LOX tanks, if not more. The volume and mass of the tank itself make them very difficult to deal with, and adding cooling system to prevent the fuel from boiling off compounds that problem even further.

Methane, on the other hand, is very dense. What it lacks in performance it more than makes up for by requiring a comparably tiny tank volume. What your rocket lacks in ISP it will more than make up for in having more propellant and less dead weight from the tanks.

Edit: I forgot to mention that electrolyzing water into H2/O2 requires very large amounts of electrical power. The Sabatier reaction (2H2O + CO2 => CH4 2O2) is vastly more energy efficient.

So, in addition to my points about the low density and high tank/support system mass involved with LH2, you'd need significant additional powerplant mass, too.

As briefly mentioned in the previous answer, H₂ is very tricky to deal with. The temperature is one thing, but what he didn't mention was its extremely low density. If I recall correctly the LH₂ tanks on the shuttle require around 4-5 times the space of its LOX tanks, if not more. The volume and mass of the tank itself make them very difficult to deal with, and adding cooling system to prevent the fuel from boiling off compounds that problem even further.

Methane, on the other hand, is very dense. What it lacks in performance it more than makes up for by requiring a comparably tiny tank volume. What your rocket lacks in ISP it will more than make up for in having more propellant and less dead weight from the tanks.

Edit: I forgot to mention that electrolyzing water into H₂/O₂ requires very large amounts of electrical power. The Sabatier reaction (2H₂O + CO₂ => CH₄ 2O₂) is vastly more energy efficient.

So, in addition to my points about the low density and high tank/support system mass involved with LH₂, you'd need significant additional powerplant mass, too.

As briefly mentioned in the previous answer, H2 is very tricky to deal with. The temperature is one thing, but what he didn't mention was its extremely low density. If I recall correctly the LH2 tanks on the shuttle require around 4-5 times the space of its LOX tanks, if not more. The volume and mass of the tank itself make very difficult to deal with, and adding cooling system to prevent the fuel from boiling off compounds that problem even further.

Methane, on the other hand, is very dense. What it lacks in performance it more than makes up for by requiring a comparably tiny tank volume. What your rocket lacks in ISP it will more than make up for in having more propellant and less dead weight from the tanks.

As briefly mentioned in the previous answer, H2 is very tricky to deal with. The temperature is one thing, but what he didn't mention was its extremely low density. If I recall correctly the LH2 tanks on the shuttle require around 4-5 times the space of its LOX tanks, if not more. The volume and mass of the tank itself make them very difficult to deal with, and adding cooling system to prevent the fuel from boiling off compounds that problem even further.

Methane, on the other hand, is very dense. What it lacks in performance it more than makes up for by requiring a comparably tiny tank volume. What your rocket lacks in ISP it will more than make up for in having more propellant and less dead weight from the tanks.

Edit: I forgot to mention that electrolyzing water into H2/O2 requires very large amounts of electrical power. The Sabatier reaction (2H2O + CO2 => CH4 2O2) is vastly more energy efficient.

So, in addition to my points about the low density and high tank/support system mass involved with LH2, you'd need significant additional powerplant mass, too.