Description: Parabilis Space Technologies (Parabilis), in collaboration with Orbital Technologies Corporation (ORBITEC), proposes to use additive manufacturing technology to fabricate a complete liquid oxygen (lox) and liquid methane Reaction Control System (RCS) thruster in response to solicitation H2.01, In-Space Chemical Propulsion. The thruster will be fabricated as a monolithic part that includes the injectors, combustion chamber, and nozzle. This thruster design will leverage a propulsion architecture especially amenable to additive manufacturing: ORBITEC's revolutionary Vortex Combustion Cold-Wall (VCCW) technology. Through additive manufacturing, Parabilis will reduce the cost, increase reliability, decrease complexity, and significantly reduce CAD-to-part design cycle time. Lox-methane is an attractive propellant combination for future NASA missions, however significant technical challenges remain. This proposed innovation provides novel solutions to challenges for lox-methane rocket engines as requested by the H2.01 solicitation. Specifically, this proposal includes innovations for RCS class thrusters, including advances in additive manufacturing, propellant injectors, and combustion chamber design. Additionally, the use of VCCW technology will likely mitigate adverse effects of multiphase or intermittent gas phase operation. Due to the low wall temperatures inherent to VCCW technology, the proposed thruster will provide almost no additional thermal loading to the main vehicle structure. The proposed thruster should obtain a vacuum specific impulse significantly in excess of 325 s for vacuum operation. Phase I development objectives include preliminary design of the thruster and cold flow testing of a thruster prototype that will be used to test the applicability of several additive manufacturing techniques. By the end of Phase I testing the technology will be at a TRL 4 level.

Benefits: The proposed thruster innovations are applicable to a number of proposed future NASA missions such as Mars exploration and sample return. Future launch vehicles utilizing Lox/methane as their main propulsion system can utilize the proposed innovation as complementary reaction control system thrusters. Additionally the technology can be scaled for use as a kick stage or orbital insertion engine. This proposed innovation meets NASA's 2014 Strategic Goal of enabling advances in manufacturing technologies for aerospace applications, by utilizing advanced additive manufacturing techniques. Additionally NASA Strategic Objective 1.1, in-space propulsion is well aligned with this innovation.

Lox/methane is an attractive propellant combination for commercial launch vehicles. Potential customers for a Lox/methane RCS engine include United Launch Alliance (ULA), SpaceX, and Firefly among others. Each of these organizations has boosters and/or upper stages that utilize the Lox/methane propellant combination in development.