India s ISRO has human-rated its CE20 cryogenic engine for Gaganyaan missions. The engine powers the cryogenic stage of the LVM3 launch vehicle. Ground qualification tests assessed thrust, mixture ratio, and propellant tank pressure. The engine for the first unmanned mission has been successfully tested.
Hydrogen fuel cells produce electricity directly from Hydrogen and Oxygen gases, along with pure water and heat. It is an electric generator which works on electrochemical principles, as in batteries, as against the combustion reactions employed in conventional generators.