Abstract: A rocket engine with porous structure is disclosed. The rocket engine can include an outer wall, a combustion chamber, a coolant distribution channel defined between the combustion chamber wall and the outer wall, and a manifold. The combustion chamber can have a combustion chamber wall, a first end, a second end opposite to the first end, and a nozzle section disposed at the second end. The manifold can be disposed at the first end of the combustion chamber and have an injector to direct a propellant into the combustion chamber and a coolant inlet to direct a coolant to flow through the coolant distribution channel. The combustion chamber wall can be manufactured through an additive manufacturing process and have a porous section to provide transpiration cooling to the combustion chamber from the coolant that flows through the coolant distribution channel.