Plasma-driven in-situ CO 2 conversion to O 2 via glow discharge under simulated Martian conditions

Abstract The in-situ resource utilization (ISRU) of the CO 2 -rich Martian atmosphere is crucial for supporting future human exploration and sustained presence on Mars. This work demonstrates the application of a direct current (DC) glow discharge plasma for the direct dissociation of CO 2 into O 2 under simulated Martian conditions. The effects of key operational parameters including gas pressure, discharge current, and gas composition were systematically investigated in terms of discharge characteristics and CO 2 dissociation performance. Results demonstrate that CO 2 dissociation is highly sensitive to discharge polarity and pressure, with negative DC polarity proving particularly effective at low pressures. Optical emission spectroscopy identified distinct peaks for CO 2 + , CO, and atomic oxygen, confirming electron-impact dissociation. The addition of 10% Ar markedly intensified the CO 2 + emission, indicative of enhanced ionization via Penning processes. In contrast, the introduction of N 2 generated emission bands from excited N 2 species, which promoted CO 2 dissociation through energy transfer; however, this process was less efficient due to competitive energy absorption by N 2 . BOLSIG+ simulations corroborated that Ar significantly increases the average electron energy and strengthens the high-energy tail of the electron energy distribution function, thereby boosting CO 2 conversion. At a specific energy input of 0.5 J · ml −1 , the addition of 10% Ar and 10% N 2 enhanced the CO 2 conversion by 16% and 12%, respectively. These findings provide valuable insights for developing scalable plasma-based ISRU systems for oxygen and fuel production on Mars, which are essential for future crewed missions.