Abstract: Functional components of spacecraft structures can be subject to detrimental impacts by energetic particles produced from an electric propulsion system. A graphene coating applied to a functional component can maintain electrical conductivity upon a surface of the functional component, thereby allowing charge dissipation to take place, while also resisting sputtering erosion resulting from impacts of the energetic particles. Accordingly, spacecraft structures can include an electric propulsion system, a functional component that is at least partially impacted by an outflow of the electric propulsion system, and a graphene coating upon the functional component. Methods for operating such spacecraft structures can include generating an outflow of energetic particles from an electric propulsion system of a spacecraft structure, and at least partially impacting the outflow of energetic particles upon a functional component of the spacecraft structure, where the functional component has a graphene coating thereon.

Abstract: Specific impulse and rocket engine efficiency can be improved by injecting reactants, e.g., a propellant combination or a monopropellant and a catalyst, into a plasma flow of a rocket engine. In some aspects, a catalyst or a propellant is carried by plasma formed by passing a flow of a feed gas through an electrical arc. In some aspects, reactants are combusted in supersonic plasma flow to generate combustion ionization in the plasma flow.