It's not two different types of fuel and all rockets do this. It's an oxidizer and a fuel. For instance a common rocket fuel is liquid hydrogen and liquid oxyge

It's not two different types of fuel and all rockets do this. It's an oxidizer and a fuel. For instance a common rocket fuel is liquid hydrogen and liquid oxygen. React the two and you get energy in the process... and water. So for instance most of the space shuttle's main engine exhaust was water vapor! Quite counter intuitive.