A Critical Review on Superconducting Semi-Cryogenic Fuels for Advanced Space Propulsion and Deep Space Missions

The exploration of deep space necessitates revolutionary propulsion technologies to overcome the vast distances involved. This review critically evaluates the potential of superconducting semi-cryogenic fuels as a game-changing approach for spacecraft propulsion. Superconductors, exhibiting zero electrical resistance at low temperatures, offer significant advantages for efficient electromagnetic thrust generation. However, achieving the ultra-low temperatures typically required for superconductivity presents logistical challenges for spacecraft. This review explores the use of semi-cryogenic fuels like liquid hydrogen and methane, enabling operation at more manageable temperatures while leveraging the benefits of superconductivity. The review delves into the challenges of boil-off loss and analyzes various mitigation techniques like multilayer insulation, 3M glass bubbles, active cooling systems, and Zero Point Boil Off (ZBO).  Furthermore, it highlights the potential performance gains of superconducting semi-cryogenic propulsion systems, including significant weight reduction and improved efficiency.  Critical considerations such as radiation exposure and the need for further research in high-temperature superconductors and computational modeling are discussed.  Overall, this review underscores the promising path that superconducting semi-cryogenic fuels offer for advancing deep space exploration.