Energy storage systems for space applications

As resource depletion looms and space technology advances, space exploration prospects are growing. To ensure a sustainable and efficient transition through inhospitable space and towards lunar and Martian outposts, critical technology must be evaluated, enhanced, and developed. A central component of space technology is energy storage systems. Energy storage is needed for satellites, probes, and rovers to evaluate planetary conditions; orbital and gateway space stations to conduct essential experiments and connect far-away places; space shuttles, landers, and extra-vehicular activity suits for safely transporting humans and cargo to their extraterrestrial destinations; and surface mobilizers and outposts for experimentation and settlement. Each of these applications has unique constraints and challenges which require equally unique energy storage systems. Compared to their terrestrial counterparts, space energy storage systems must be able to withstand severe radiation, extreme cycling, intensive temperature fluctuations, and vacuum pressures; all within incredibly stringent specific energy and energy density parameters. This review presents a systematic evaluation of energy storage systems including batteries, fuel-cell and electrolyzer systems, thermal energy storage systems, supercapacitors, and flywheels. A framework is developed to evaluate the technologies in the context of specific outpost and transport application categories. These categories represent applications with similar engineering requirements. This included specific energy, energy density, cycle life, shelf-life, and temperature tolerance. Lithium-ion batteries and fuel-cell systems promise high reliability, flexibility, and utility across a broad range of these categories. These technologies are undergoing continual improvement and development for space applications. Non-flow through fuel-cells, integrated fuel-cells for boil-off control, solid oxide regenerative fuel-cells for in-situ resource utilization, developmental Li-CF_x cells with MnO₂ blending, and modified commercial-off-the-shelf lithium-ion batteries are being investigated. As space exploration advances, energy systems derived from Lunar and Martian resources become ever-more important. Additively manufactured electrochemical devices and thermal wadis from regolith may be a central part of future space energy storage systems. As with many of the key technologies vital to present-day life, these developments for space application may reveal terrestrial utility. As these technologies continue to meet and exceed engineering requirements, new opportunities arise for continued space exploration, travel, and settlement.