U chemists are using the most out-of-this-world laboratory in the universe: the International Space Station.
Researchers started a six-month trial that astronauts will run from the ISS, testing a new method for monitoring water quality to ensure that astronauts remain healthy.
The water-monitoring system was launched into space Aug. 28 aboard the space shuttle Discovery. The first test will take place Sept. 22, and the astronauts will conduct more tests each following month. NASA, the Utah Science Technology and Research Economic Development Initiative, Arizona State and Iowa State are funding the project.
“As humans move further into space and have longer space missions, NASA will need to recycle materials such as drinking water,” said Marc Porter, U professor of chemistry and chemical engineering. “The challenge is to be able to clean the water enough to make it drinkable.”
NASA uses iodine as a disinfectant on U.S. space crafts, and Russians use pure-silver nanoparticles that at low levels are non-toxic, but it’s a balancing act. If the levels of iodine and silver in the water are too low, microbes will grow, Porter said. Levels of iodine that are too high result in bad-tasting water that the astronauts will not drink, putting them at risk for dehydration. A long-term effect of drinking an excess of iodine is the possibility of developing thyroid problems. Excess levels of silver can permanently turn the skin a grayish-blue color.
Because of the lack of onboard techniques, every few months when the shuttles return to earth, water quality on space stations or shuttles is analyzed on the ground from samples brought back, said Lorraine Siperko, a senior research scientist in Porter’s laboratory. As missions are getting longer, the space stations need to become more independent and able to detect the amounts of the disinfectants in the water.
“You have to be able to get water purified and know it’s pure,” Siperko said. “NASA wants to know immediately if there is enough disinfectant in the water. especially with more lunar and Mars missions in the future.”
The new method takes samples of the water from the space stations and forces them through a chemical-saturated, disk-shaped membrane, which then changes in color. The astronauts would use a color sensor, much like the color strips to test the amount of chlorine in a pool, to detect if the levels of iodine or silver are high enough to kill any microbes in the water, Porter said. The amount of iodine in the water depends on the intensity of the color it turns: the brighter the yellow, the more iodine there is in the water, and a brighter pink indicates the amount of silver.
“We feel really confident that this will work,” Siperko said. “NASA has really rigid guidelines as to what can go on their space shuttles. You have to go through all the toxicology and radiation testing, as well as to make sure that the system works in space.”
To ensure that the system would work in a zero-gravity situation, Porter and his team went to Johnson Space Center and rode what is jokingly called the “Vomit Comet.” During the flight, a plane flying at about 25,000 feet in the air will incline at a 45 degree angle until about 35,000 feet where it will then slowly come back to Earth, essentially creating an arch. Zero gravity is reached at the top of the arch for about 25 seconds.
The researchers broke up the steps to operate the system, which takes about two minutes, into shorter time segments. Each time around the arch, they would pass the system around until they finished. The results were then analyzed on the ground and adjustments made before trying it again.
The water quality system can also be used on the ground to test for various water contaminations such as chromium, cadmium, nickel and other heavy metals, said Siperko. The method is in the process of being modified to check the amounts of arsenic, a natural pollutant in the southwest and northeast parts of the United States and in Bangladesh.
Photo courtesy of NASAFrom left to right, Bob Lipert, of Iowa State University, John Straub, of Wyle Laboratories, and Lorrine Siperko of the U work on a water quality monitoring system while experiencing weightless conditions.