Advanced Manifolds for Improved Solid Oxide Electrolyzer Performance

In late 2013 NASA GRC proposed an in-situ resource utilization (ISRU) experiment on the Mars 2020 rover mission. This proposal was one of the two highest-rated proposals, in part because of the unique design of the GRC Bi-Supported Cell (BSC) solid oxide electrolyzer (SOE) at the core of the ISRU oxygen production module. However, as the team performed pre-phase A work during the first half of 2014, we identified a need to modify the gas manifolds for the SOE stack to reduce stresses on the ceramic components. We began to discuss the potential to switch from a slip-cast manifold fabrication to 3D printing to reduce the number of parts, eliminate sharp corners, allow for more gradual transitions, and enable more efficient flow paths. The production of oxygen from the carbon dioxide in the Mars atmosphere to produce roughly 23 metric tons of ascent propellant is included in NASA's baseline Mars human exploration architecture. The use of SOEs for extracting the oxygen is the leading technology candidate due to its system-level simplicity. However, ISRU technical leaders in the agency still have doubts about ever being able to develop large SOE stacks using the traditional construction. Therefore, they are continuing to consider a reverse-water-gas-shift system as a back-up technology option for the human exploration missions in spite of the SOE system being 85 percent lower mass, 65 percent less volume, and requiring 88 percent fewer components. The demonstration of a robust and efficient manifold will complete the proof-of-concept for the innovative BSC SOE stack design and provide compelling arguments to ISRU leaders to invest further in this GRC technology. The goal is to advance the TRL of the GRC BSC SOE and fuel cell concept to realize performance, mass, and volume advantages of this innovative design for Mars O2 production. More »