Planetary Pros: Liquid hydrogen is a very efficient rocket fuel, offering excellent “specific impulse” – that just means the amount of thrust produced for each unit of fuel consumed.
It provides high energy density, meaning it’s great for propulsions – that’s the push that carries the rocket forward.
It’s also great because there’s lots of hydrogen available, and its combustion produces clean exhaust, consisting mainly of water vapor, making it more environmentally friendly.
Cosmic Cons: One major drawback of liquid hydrogen is that because it has a low density, it takes up a lot of space and needs larger storage tanks compared to other fuels.
This adds weight and volume to the rocket, making it overall potentially less efficient.
Hydrogen is also tricky to store and handle due to its extremely low boiling point and its tendency to leak through materials.
Producing liquid hydrogen can use a lot of energy which makes it expensive to make.