Fuel cell development for space applications in a micro-gravitational and closed environment

National Space Development Agency of Japan (NASDA) is developing Polymer Electrolyte Fuel Cell (PEFC) systems for applications to transfer vehicles for short-term missions and larger spacecraft in the future. We first designed and manufactured a 1 kW-class fuel cell. Through our tests, we demonstrated that a humidifier is not necessary when using pure hydrogen and oxygen supplied from opposite directions. Furthermore, we prepared a dehydrator and demonstrated water removal from closed gas loop for future operations in a closed environment. We demonstrated more than 250 hours of operation with stable performance in a simulated closed environment.