Abstract: A method includes depositing beads of solid propellant material using additive manufacturing to form a fuel element for a rocket engine, the fuel element including beads of solid propellant material, wherein a combustion port extends through the fuel element, wherein the solid propellant material includes an oxidizer and a binder material.

Abstract: A fuel grain for a hybrid rocket engine includes multiple layers of fuel grain material defining a combustion port extending through a body of the fuel grain, in which each layer includes multiple beads of fuel grain material, in which the multiple beads in a given layer are disposed adjacent to one another and bonded together, and in which adjacent layers are bonded together, in which each bead of fuel grain material includes a polymer based rocket fuel material, and in which a composition of the beads of the fuel grain material, a form of the beads of fuel grain material, or both varies within the fuel grain.

Abstract: A catalyst bed includes a structure defining a plurality of channels configured to receive flow of fluid to be chemically catalyzed. The plurality of channels are oriented at least partially non-parallel to an overall flow direction of the flow from inputs of the plurality of channels to outputs of the plurality of channels. A catalyst is exposed at an exterior of the structure.

Abstract: A catalyst bed includes a structure defining a plurality of channels configured to receive flow of fluid to be chemically catalyzed. The plurality of channels are oriented at least partially non-parallel to an overall flow direction of the flow from inputs of the plurality of channels to outputs of the plurality of channels. A catalyst is exposed at an exterior of the structure.