April 4, 2005
A Little Sweat Goes a Long Way for Exploration
NASA -- There's a whole lot of sweating going on in one building at NASA's Marshall Space Flight Center in Huntsville, Ala.
Marshall Center employees are donating their time, energy -- and sweat -- during monitored exercise on bikes, rowing machines and treadmills to test part of the life support system that provides the International Space Station with clean air, a comfortable living environment and drinkable water.
The system is called the Regenerative Environmental Control and Life Support System, or ECLSS. NASA engineers at the Marshall Center are responsible for designing and developing the Water Recovery System, which reclaims potable water from Space Station wastewater, including crew latent -- condensed water vapor and trace contaminants from crew perspiration and respiration -- and urine.
The Water Recovery System includes a Urine Processor, designed, assembled and tested in-house at Marshall that recovers water from urine. This resulting "product" is then combined with the crew latent for processing to attain potable quality by the Water Processor Assembly.
That assembly, provided to NASA by Hamilton Sundstrand Space Systems International of Windsor Locks, Conn., cleans wastewater through a series of treatment processes. Those processes primarily include adsorption, which takes the organic contaminants such as caprolactam, which comes from Velcro, out of the water; ion exchange, which takes salt out of the water; and catalytic oxidation, which removes the volatile organics such as methanol and other contaminants that adsorption and ion exchange do not remove.
"The resulting product water is cleaner than municipal water on Earth," said Layne Carter, lead systems engineer for the Water Processor at Marshall. "On the Station, this water will be used by the crew for everything from drinking to hygiene activities, as well as the operation of payloads."
To reduce costs and take advantage of existing facilities, the qualification test of the Water Processor Assembly treatment process is being performed in the ECLSS Test Facility at Marshall. The recovered water must meet stringent purity standards before it can be used to support the crew. That's why these tests use the actual chemical "beds," or expendables, that will process water on the Station.
The objective of the tests is to verify the entire assembly works properly. The chemical "beds" are part of the Water Processor Assembly that removes the different types of contaminants from the water so that it can be re-used by the crew as potable water.
More than 100 employees are participating in the Water Processor Assembly Expendables Qualification Test. For the study, they exercise for an hour a day, generating water vapor through perspiration and respiration, in the Regenerative ECLSS Module Simulator -- a mockup of a Space Station module filled with treadmills, a bicycle, rowing machine and other exercise equipment. They also brush their teeth, wipe themselves down with wet towels and male participants even shave -- simulating the daily routine of a Station crewmember -- to get every bit of moisture into the atmosphere.
"It's my chance to get in shape, literally to contribute to science and prove this equipment -- that our people here have worked to design and build -- works flawlessly," said Gray Marsee, an attorney who is participating in the tests. "I'm literally donating my sweat to the Space Station and future exploration."
Before stepping into the mockup for a session, participants are provided with a white T-shirt to wear, a towel for drying off and a bottle of water or a sports energy drink to consume as they exercise. They weigh-in on a computerized scale, with the bottle of water in-hand.
"We want to see how much weight goes in and calculate how much condensate is left inside the module," said Gene Hartsfield, manager of the ECLSS test facility. "The T-shirts and towels are left hanging inside overnight to evaporate to get more sweat out of them and into the condensate."
Meals also are an important part of the testing. The participants microwave meals inside the module to generate water vapor and the aroma from the food. The condensate is then combined with the Urine Processor product and sent to the water processor for treatment. Water quality samples are taken at key locations in the water processor to assess the performance of the expendables and determine how often they must be replaced.
The testing began in October and is expected to wrap up later this month. The results will verify the water processor chemical "beds" are ready to fly in 2007.
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