Study of Water Electrolysis under Microgravity Condition for Oxygen Generation

Date

2016-07-10

Journal Title

Journal ISSN

Volume Title

Publisher

46th International Conference on Environmental Systems

Abstract

To further advance manned space exploration, a critical issue that must be addressed is recycling of resources, especially air revitalization and water reclamation. JAXA plans to achieve early in-orbit demonstration of regenerative ECLSS technologies during the extended ISS operation period. JAXA aims to apply terrestrial environmental technologies to develop air and water recycling technologies for space applications. 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 was carried out as ground base experiment. Each air and water re-vitalization subsystem is planned to be transported to the ISS. This paper presents the air re-vitalization system developed by JAXA, and gives details of water electrolysis in microgravity. A technical issue with space water electrolysis systems is that gas-liquid separation is fundamentally different in a microgravity environment to its behavior in a gravity field. It is supposed that the electrode surface will become covered with generated gas. In microgravity, the gas will have to be removed using forced convection. A water/gas separator will be used to separate gas and water. A membrane type water/gas separator consisting of hydrophilic and hydrophobic membranes was used. A prototype of the water electrolysis ground experiment system incorporating the water/gas separator was operated as a ground base experiment. The water electrolysis system was installed on a gravity direction test bed to evaluate the effect of gravity on the system with different gravity directions. Furthermore new type of water electrolysis cell for microgravity is fabricated.

Description

Japan
JAXA
302
ICES302: Physio-chemical Life Support- Air Revitalization Systems -Technology and Process Development
Vienna, Austria
Takuma Terao, Japan Aerospace Exploration Agency, Japan
Masato Sakurai, Japan Aerospace Exploration Agency, Japan
The 46th International Conference on Environmental Systems was held in Vienna, Austria, USA on 10 July 2016 through 14 July 2016.

Keywords

Life support system, Oxygen generation, Water electrolysis, Microgravity, Liquid/gas separation

Citation