Japanese Experiment Module Airlock Pressurization/Depressurization System Design and Development

The Japanese Experiment Module (JEM), being provided by NASDA for International Space Station Alpha (ISSA), is a multipurpose research and development laboratory providing a shirt-sleeve environment for astronauts. The JEM will be equipped with power supply, thermal control, environmental control and life support, and data handling systems. The primary components of the JEM include a pressurized module and an exposed experiment facility. The pressurized module includes an airlock to facilitate transfer of equipment and supplies from within the pressurized module to the exposed facility. The JEM airlock has been designed to conserve air by pumping air from the airlock into the pressurized module prior to opening the outer airlock door to space vacuum. This is accomplished through use of the airlock pressurization/depressurization system (APDS). The APDS also admits air back into the JEM during pressurization. The JEM APDS is comprised of three subsystems: a dehumidifier assembly, a valve assembly, and an airlock depressurization unit. Development testing of the dehumidifier and valve assembly is currently in progress as part of the engineering model (EM) phase of the APDS program. This paper summarizes the required functions and overall design of the APDS, and describes the history and development/evolution of some of the specific components which have been selected.