On the space station, "once per month they will check the water for iodine and silver," Siperko says. "That data will be downloaded and relayed back to Earth, to Johnson Space Center" in Texas.
"We have teleconferences with them, and they will transfer the data to us electronically for us to look at," she adds. "That way we can judge if the experiment is working correctly. If any unforeseen problems arise, then we can advise them as to what we think might be the problem and how to correct it."
Keeping It Clean in Orbit
The project began a decade ago, before Porter joined the Utah faculty, when NASA sought proposals for disinfectant or "biocide" monitors to check the safety of drinking water on manned spacecraft.
"You can't sterilize water well enough to keep things from growing in it," Porter says. "Nature happens."
NASA uses iodine as a disinfectant on U.S. spacecraft. The Russians use colloidal silver pure silver nanoparticles, some of which go into solution.
The problem for both iodine and silver is that microbes grow in the water if levels are too low. If levels are too high, iodine-treated water tastes bad and eventually might cause thyroid problems, and silver at excessive levels can turn the skin grayish blue.
Space station water now is sampled and returned to Earth for testing at intervals of months because "they don't have an acceptable onboard technique," Porter says.
He says the space station is a proving ground for technologies for longer manned flights to the moon and Mars even though those flights are unlikely anytime soon due to high costs and other priorities.
Water for astronauts is carried into orbit and also produced on the space station as a byproduct of hydrogen and oxygen reacting in fuel cells. Disinfectants or biocides are added during flight, but actual levels in drinking water cannot be tested until samples are brought ba
|Contact: Lee Siegel|
University of Utah