Analysis on degassing at microgravity condition

Abstract

For the future diversity and sustainability of the International Space Station, the manned flight time will be greatly increased, and the water required will be greatly increased as well. It is particularly important to deal with resources in more detail. In the process of treating drinking water, tiny air bubbles may be created. Bubbles can form in the Water Recovery and Management System (WRMS) on the ISS due to gas dissolution, microgravity environment, chemical reactions, and microbial metabolism. Water under pressure can dissolve gases. In the ISS, if water comes from a high-pressure environment to a lower one, gas may come out of solution, forming bubbles. Also, in the microgravity environment of the ISS, bubbles can remain suspended in the water, interfering with the systems sensors and pumps. Some processes in the water recovery system can produce gases as byproducts, such as electrolysis used in the Oxygen Generation System of the ISS. Finally, some microbial metabolic processes generate gases which can form bubbles in the water. According to four reasons given above, the passage will first introduce the current situation about dealing with bubbles in ISS, then providing some future directions of the development of the bubble-remove techniques.