NASA Brings Clean Water Back Down to Earth

Getting enough water is one of the greatest challenges in human spaceflight. As its mission objectives have become increasingly more ambitious, NASA has been at the forefront of water purification technology. Designers of water purification systems for space travel face many of the same challenges as designers of systems for use in developing nations, and many of the purification systems developed by NASA have been adapted for use here on Earth.

Water purification technology from the Apollo lunar missions has been successfully commercialized, and a system based on the Space Shuttle’s water purifier is widely in use in developing nations today. Currently, NASA is developing even more advanced water purification systems for use on the International Space Station and future outposts on the Moon and Mars. While this most recent technology is more advanced than necessary for most current applications, it may still eventually contribute to making people’s everyday lives better right here on Earth.


What has NASA done for you lately? While the name of the U.S. space agency may evoke images of rockets soaring out of the atmosphere on pillars of flame many technologies developed for the space program have been adapted for everyday use here on Earth. NASA calls these commercialized technologies “spinoffs,” and there are thousands of them affecting our lives today, improving everything from medicine to computer technology . The classic example that comes to mind for most people is the orange-flavored breakfast drink Tang, although it is not a true spinoff. Tang was actually developed before human spaceflight began, but it did gain popularity after NASA used it on the Gemini missions [1]. For people in disaster areas or developing nations, though, NASA spinoffs can mean improved access to a far more essential drink: pure water. Technology developed by NASA to provide clean water to astronauts on long-duration space missions is being adapted and implemented for better water purification on Earth.
The Need for Water Purification
Getting enough water is one of the greatest challenges in human spaceflight. Human beings cannot survive without water, but water is heavy and it occupies a large storage volume. In the early days of human spaceflight, when missions lasted only a few hours or at most several days, it was possible to launch space travelers from Earth with all of the water they needed. However, as mission plans lengthened, bringing water from Earth to sustain human life for extended periods became less feasible. Instead, researchers began to develop water purification technology to recycle the limited water supply that could be provided.
While astronauts face challenges in getting enough water to survive in space, many more people have the same problem in developing nations down here on Earth. According to the World Health Organization, 1.1 billion people, or 17% of the global population, lacked access to a safe water source in 2002. Interestingly, designers of water purification systems for space travel face many of the same challenges as designers of systems for use in developing nations. The key features of equipment suitable for both settings are durability, simple design, and low maintenance requirements. Obtaining specialized parts or personnel experienced in water system repair can be equally difficult in space and in developing nations. Given these similarities, water purification technology designed for NASA can be very useful to developing nations if the right adaptations are made to it [12].

Proven NASA Water Technology
NASA began developing spacecraft water purification systems for the Gemini program in the 1960s to back up water supplies brought from Earth [2]. Its first successful spinoffs in this area came from Apollo-era technology, though. For the lunar missions, NASA developed a lightweight water purifier the size of a cigarette pack that was designed for minimal power consumption and monitoring. Later, a private company obtained NASA’s permission to modify the purifier for commercial and industrial use.

The commercial system passes a small electrical current through copper and silver electrodes, releasing ions into the water being purified. The ions kill bacteria and algae in the water by breaking down their enzymes, and the ions and dead organisms are then filtered out of the water. This is similar to the way that chlorine is used in swimming pools, but metallic ions are more stable and less irritating to the human body than chlorine ions. This water purification system is now used in swimming pools, fountains, and cooling towers [3].

Commercial technology geared more toward drinking water purification came from NASA’s Space Shuttle program. The Apollo spacecraft were designed for one trip, but the Space Shuttle is reusable, so it requires a longer-lasting water purification system. In the Space Shuttle, water is passed through a bed of tiny resin beads containing iodine; this process introduces iodine ions into the water supply that work in the same way as chlorine or metallic ions. The resin bed does become depleted over time, so to lengthen the interval between replacements, the bed is recharged with iodine by periodically flowing the water over iodine crystals before passing it through the resin beads [4].

This technology has been successfully adapted into commercial units that purify approximately 5 gallons (about 20 liters) of water per minute. Because the units do not require electricity, they are ideal for developing countries or emergency situations after natural disasters, when power might not be available

Global Development for Community Drinking Water

Figure 2: Concern for Kids volunteers installing water purifier that uses Space Shuttle technology in Iraq.
Commercialized purifiers using NASA’s Space Shuttle technology have been successfully implemented worldwide. In 1994, for example, the prime minister of Vietnam endorsed an order for 10,000 of these iodine-based purification units [4]; this was estimated to provide clean water to 50 to 70 million people [5]. In 1998, the company that originally adapted the NASA technology reported over $10 million in sales of these purifiers since their introduction [6]. Other companies have continued to improve the technology; in 2006, a non-profit organization called Concern for Kids purchased an upgraded purification unit and installed it in the village of Kendala, Iraq (see Fig. 2) with the help of NASA engineers who were designing the next generation of water purification systems for space travel[7].
Current Developments

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