NASA has accorded top priority in expanding the longevity of life-support systems at the International Space Station by testing new materials and is keen on leveraging them for the upcoming long-duration flights to Mars and beyond.
Accordingly, NASA sent the Long Duration Sorbent Testbed (LDST) in the ninth SpaceX resupply mission to the ISS on July 18.
The test bed is kind of a test dose in ascertaining which substance is the most suitable for collecting molecules and filtering them in long-duration missions such as Mars mission.
The LDST has been sent with 12 different materials, and based on the exposure to the ISS environment, the final selection will be made depending on the maximum carbon dioxide removal capacity.
This is because the "scrubbers" already placed on the station requires faster water removal and easy processing of carbon dioxide and treatment of hydrogen discharged from the oxygen generator for producing water. In a space station, water is the most wanted commodity for survival.
Closed Environment
"There is a complex atmosphere on the space station," noted Jim Knox, an aerospace engineer at Marshall.
Knox observed that the mix of environmental contaminants in ISS is a new domain for them. Referring to LDST, he said selecting materials for future systems depends on how those materials react with contaminants and how better are the filters built.
On new materials, David Howard, program manager of the investigation at Marshall, said this is required because exposure to the unique environment in the space station would change the behavior patterns of many materials.
Currently, the space station uses a silica gel to erase humidity from the air, and it works in conjunction with hardware to scrub carbon dioxide from the air before it goes toxic.
However, within a year, the gel loses 75 percent of its water absorption capacity and requires replacement.
According to engineers, the reason of gel losing efficiency is the aftereffect of 200 recorded contaminants present in the ISS environment.
Urine Recycling
Meanwhile, a new chemical solution called Alternate Urine Pretreatment (AUP) has been developed for achieving optimum recycling of the urine into the water at the space station.
Under the new mechanism, while flushing the toilet on the station, a few milliliters of AUP needs to be added for ensuring higher water-recovery percentage and for reducing mineral buildup inside the tubes so that clogging can be reduced.
The AUP was installed on the station on May 17 by NASA astronaut Jeff Williams, expecting 90 percent recovery rate.
The urine treated with AUP gets distilled and polished in the Water Reclamation System before being sent for the consumption of crew in space.
This is a major achievement in water-recycling technologies considering the potential for application in long-duration space voyages such as Mars mission.
"The goal is not to take large amounts of water with us to space, but to be able to take the water cycle itself to space," said Dean Muirhead, a space engineer with Barrios Technology.
