Search Results

NASA is investigating the use of plant growth chambers (PGCs) for space missions and for bases on the moon and Mars. Key to successful development of PGCs is a system to recover and reuse the water vapor that is transpired from the leaves of the plants. In this paper a design is presented for a simple, reliable, membrane-based system that allows the recovery, purification, and reuse of the transpired water vapor through control of temperature and humidity levels in PGCs. The system is based on two membrane technologies: 1) dehumidification membrane modules to remove water vapor from the air, and 2) membrane contactors to return water vapor to the PGC (and, in doing so, to control the humidity and temperature within the PGC). The membrane-based system promises to provide an ideal, stable growth environment for a variety of plants, through a design that minimizes energy usage, volume, and mass, while maximizing simplicity and reliability.

Humidity control is essential in the extravehicular mobility unit (EMU). Excessive humidity can lead to visor fogging; accumulation of water, which can block air flow through the vent loop and corrode system components; and uncomfortable conditions for the person inside the EMU, reducing productivity. This paper describes the development of a membrane-based process for dehumidifying the EMU. The membrane process promises to be smaller, lighter, and more energy efficient than the other technologies being considered for dehumidification, and it requires no expendables. The system employs novel dehydration membranes, which were tested for 90 days at conditions expected to be present in the EMU. The results of these tests indicate that membrane-based technology can effectively control humidity in the EMU.