International Space Station USOS Potable Development Water Dispenser

The International Space Station (ISS) Russian Segment currently provides potable water dispensing capability for crewmember food and beverage rehydration. All ISS crewmembers rehydrate Russian and U.S. style food packages from this location. A new United States On-orbit Segment (USOS) Potable Water Dispenser (PWD) is under development. This unit will provide additional potable water dispensing capability to support an on-orbit crew of six.

The PWD is designed to provide incremental quantities of hot and ambient temperature potable water to U.S. style food packages. It will receive iodinated water from the Fuel Cell Water Bus in the U.S. Laboratory element. The unit will provide potable-quality water, including active removal of biocidal iodine prior to dispensing. A heater assembly contained within the unit will be able to supply up to 2.0 liters of hot water (65 to 93°C) every thirty minutes. This quantity will allow three to four crewmembers to rehydrate their food and beverages from this location during a single meal. The unit is designed to remain functional for up to ten years with replacement of limited life items such as filters. It will be the size of two stacked Shuttle Middeck lockers (approximately the size of two small suitcases) and integrated into a science payload rack in the U.S. Laboratory element.

Providing potable-quality water at the proper temperature for food and beverage reconstitution is critical to maintaining crew health and well-being. The numerous engineering challenges as well as human factors and safety considerations during the concept, design, and prototyping are outlined in this paper.