Electrochemistry to Power out-Earth Basecamps for Space Exploration

Abstract

In a decade or so, the International Space Station will be done with. The $150bn outpost will plunge back to Earth in a fireball above the Pacific Ocean leaving astronauts with nowhere to go. If humans want to maintain a presence in space, they need a new plan, and soon. Future of human space exploration is then the perspective of building space villages stepping space exploration. While NASA remains fixated on sending people to Mars, ESA sees the moon as the next venture for a long time to come. In any case one major challenge similar to earth is powering those space planet habitats. With the recent focus on human missions to the moon and eventually Mars, hydrogen will continue to be innovatively stored, measured, processed and employed. Beyond use as a rocket propellant, hydrogen may be derived from local water or soil to supply fuel for transportation, electrical power and crewmember breathable oxygen. For instance, on the International Space Station, water is split into oxygen for breathing and hydrogen. In the former space programs (GEMINI, APOLLO, space shuttle), fuel cells were already used to power the different space ships. In the future, hydrogen will be recombined with exhaled carbon dioxide for water renewal. Generating and recycling hydrogen in space will decrease the cost and complexity of remote missions by reducing the need for supplies delivered from Earth. By the way, Fuel Cells are also alternative power sources for mobility of various aerospace vehicles complementary to primary or secondary batteries. On earth, Power-to-gas—which offers the advantage of being able to store surplus energy as gas—is expected to play a role in facilitating the integration of intermittent renewable energy into our grids. Surplus electricity is used to produce hydrogen via a water electrolysis process. The hydrogen then reacts with CO2 in a methanation reactor, producing synthetic methane. The methane can either be injected back into the grid or used to fuel gas-powered vehicles. Today earth demonstrators unit are built on technology developed by the CEA, which leverages a compact milli-structured plate reactor developed by LITEN, a CEA Tech institute. Therefore today CEA-LITEN is pursuing a variety of alternative power sources, for terrestrial and aerospace vehicles. In a global approach also pursuing power generation and electrolysis systems offering a global autonomous energy solution. Those alternatives include primary and secondary batteries with a disruptive approach to increase performance and safety (“Post Lithium-ion” batteries), Fuel Cells with significant advances in the development of Proton Exchange Membrane (PEM) fuel cells using hydrogen and air or pure oxygen as the fuel and oxidant for land, air or water mobility applications. LITEN is also involved in developing reversible Solid Oxide Fuel Cells (SOFC) / Solid Oxide Electrolysis Cells (SOEC) for ground-based power generation. CEA is today building upon these PEM and SOFC developments advance technologies, providing reliable, compact and high-energy renewable power sources for terrestrial applications similar to those foreseen by NASA for aerospace. Batteries, Fuel Cells, Electrolysis… All those systems usually covered at system or components level in the aerospace field have one common thread: they are all made thanks to Electrochemistry fundamentals highlighting the many ways in which electrochemistry enables so many space-related activities. In this work we will discuss how recent terrestrial advances and current challenges are creating more and more opportunities for electrochemistry in space while having to face space harsh conditions.