I’m sorry, when did the subject shift from automotive technology to astrophysics?
In the context of this thread, hydrogen is NOT a fuel. It is an energy transport medium. If we could _find_ free hydrogen in (or convertible to) a suitable form, it could be considered a fuel. Alas, it takes more energy to produce/release the hydrogen we need in a practical form than we get from using it, so it’s just a mechanism for storing & moving energy.
Ding ding! Tag team!