Asuka Shima

Air Revitalization in Orbit Demonstration for a Future Long-Duration Manned Mission

Various space agencies are currently considering the moon and asteroids as way stations for astronauts bound for Mars. Under JAXA’s long-term vision, JAXA2025, the agency will by 2015 finalize its development plans for the next period of manned space activity. To establish supporting technologies, JAXA is researching systems that will be indispensable for manned space activities beyond low earth orbit, including water and air recycling. Three types of assemblies are necessary for recycling air: a carbon dioxide separator to remove exhaled carbon dioxide from a spacecraft’s atmosphere, a carbon dioxide reduction assembly to produce water from the separated carbon dioxide and added hydrogen, and water electrolysis equipment for oxygen production. This paper describes a carbon dioxide removal assembly and a water electrolysis assembly designed for operation in microgravity.

CO 2 Methanation on Co-sputtered Ru–Metal Oxides Catalysts Prepared Using the Polygonal Barrel-Sputtering Method

CO2 methanation catalysts were prepared by co-sputtering with Ru and metal oxides such as TiO2 and ZrO2 using the polygonal barrel-sputtering method. The co-sputtering technique not only resulted in the decrease in the reaction temperature but also maintained the deposition of smaller Ru particles during the reaction at higher temperature.Graphical Abstract

Air Revitalization Demonstration on the JEM (KIBO) for a Manned Space Exploration

To further advance manned space exploration, a critical issue that must be addressed is recycling of resources, especially air revitalization and water reclamation. Japan is already a leader in terrestrial environmental technologies, and aims to apply this know-how to develop air and water recycling technologies for space applications. To support proposed post-ISS missions such as manned lunar or asteroid exploration and an Earth-Moon Lagrange point (EML1) space station, JAXA is developing an air revitalization system for an on-orbit demonstration on the International Space Station (ISS) early in the extended ISS operation period (2015–2020). The requirements for this technical demonstrator have been investigated and its specifications established. Regenerative life support functions include oxygen recovery from carbon dioxide using a combination of CO2 reduction by a Sabatier process and O2 generation by electrolysis. Each air and water re-vitalization subsystem is planned to be transported to the ISS separately by successive H-II Transfer Vehicle (HTV) launches in the sequence Water Reclamation → Water Electrolysis → CO2 Reduction. This paper presents the air re-vitalization system developed by JAXA, and gives details of water electrolysis in microgravity.

Study for the Reduction of Carbon Dioxide Using Sabatier Reaction

The Sabatier reaction with a titanium dioxide (TiO2)-supported ruthenium (Ru) catalyst (Ru/TiO2) was investigated with the goal of scaled-up carbon dioxide (CO2) methanation at lower temperatures than conventional catalysts. The catalytic reaction of stoichiometric amounts of CO2 and hydrogen (H2) without any diluting was conducted over a 0.75 wt% Ru/TiO2 (Ru/TiO2(0.75)) at several flow rates. The CO2 reduction was achieved with catalyst temperatures less than 300°C in good to excellent conversions. Transmission electron microscopy (TEM) and scanning transmission electron microscopy-energy dispersive X-ray spectroscopy (STEM-EDX) images of Ru/TiO2(0.75) revealed highly dispersed Ru nanoparticles having one to a few nanometers’ diameter on the TiO2 supports. The physical properties of Ru metals are considered to contribute the decrease of the reaction temperature.