Development of an efficient alternative to recovery O2 from metabolic CO2 via electrolysis operated at ambient temperature and driven by a highly selective catalysis

The current State of Art (SOA) on oxygen recovery onboard the Environmental Control and Life Support System (ECLSS) at the International Space Station (ISS) is a complex, heavy, and power-consuming system that recovers approximately 50% of the oxygen (O2) from metabolic carbon dioxide (CO2). For future long-duration beyond low Earth orbit (LEO) missions, O2 recovery systems will need to be highly reliable, and efficient, and recover a minimum of 75% O2 from metabolic CO2. An alternative technology development effort currently underway at NASA Marshall Space Flight Center (MSFC) has the potential to significantly increase O2 recovery currently limited to 50% (Sabatier) and reduce the complexity of ECLSS O2 recovery. MSFC and the University of Texas in Arlington (UTA) have jointly designed and fabricated a microfluid electrochemical reactor (MFECR) that operates at ambient conditions and utilizes a proprietary catalysis highly selective on reducing CO2 to ethylene (C2H4) at the cathode while O2 is generated at the anode. The MFECR would replace three pieces of hardware for future ECLSS architectures: the current CO2 Reduction Assembly (CRA) (Sabatier reactor), the Plasma Pyrolysis Assembly (PPA), and the Oxygen Generation Assembly (OGA). It is designed to interface directly with the CO2 Removal Assembly (CDRA) and the Water Processing Assembly (WPA) to supply CO2 reactant and water replenishment respectively. This is expected to substantially improve the sustainability of the ISS ECLSS and reduce requirements on power and weight. Here, we discuss the current development and evaluation efforts on different alternatives on not only the configuration and setup of the MFECR at an Engineering Design Unit (EDU) scale but also the selection of component materials.