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By European Space Agency
Space is not the safest place to be. During spaceflight, both devices and humans risk exposure to high levels of radiation. Without sufficient protection, instruments would malfunction, and astronauts might face serious health risks. A team of researchers from Ghent University in Belgium are testing the potential of 3D-printed hydrogels – materials that can soak up large amounts of water – to serve as highly-effective radiation shields.
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By NASA
3 Min Read NASA Scientists Find New Human-Caused Shifts in Global Water Cycle
Cracked mud and salt on the valley floor in Death Valley National Park in California can become a reflective pool after rains. (File photo) Credits: NPS/Kurt Moses In a recently published paper, NASA scientists use nearly 20 years of observations to show that the global water cycle is shifting in unprecedented ways. The majority of those shifts are driven by activities such as agriculture and could have impacts on ecosystems and water management, especially in certain regions.
“We established with data assimilation that human intervention in the global water cycle is more significant than we thought,” said Sujay Kumar, a research scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and a co-author of the paper published in the Proceedings of the National Academy of Sciences.
The shifts have implications for people all over the world. Water management practices, such as designing infrastructure for floods or developing drought indicators for early warning systems, are often based on assumptions that the water cycle fluctuates only within a certain range, said Wanshu Nie, a research scientist at NASA Goddard and lead author of the paper.
“This may no longer hold true for some regions,” Nie said. “We hope that this research will serve as a guide map for improving how we assess water resources variability and plan for sustainable resource management, especially in areas where these changes are most significant.”
One example of the human impacts on the water cycle is in North China, which is experiencing an ongoing drought. But vegetation in many areas continues to thrive, partially because producers continue to irrigate their land by pumping more water from groundwater storage, Kumar said. Such interrelated human interventions often lead to complex effects on other water cycle variables, such as evapotranspiration and runoff.
Nie and her colleagues focused on three different kinds of shifts or changes in the cycle: first, a trend, such as a decrease in water in a groundwater reservoir; second, a shift in seasonality, like the typical growing season starting earlier in the year, or an earlier snowmelt; and third a change in extreme events, like “100-year floods” happening more frequently.
The scientists gathered remote sensing data from 2003 to 2020 from several different NASA satellite sources: the Global Precipitation Measurement mission satellite for precipitation data, a soil moisture dataset from the European Space Agency’s Climate Change Initiative, and the Gravity Recovery and Climate Experiment satellites for terrestrial water storage data. They also used products from the Moderate Resolution Imaging Spectroradiometer satellite instrument to provide information on vegetation health.
“This paper combines several years of our team’s effort in developing capabilities on satellite data analysis, allowing us to precisely simulate continental water fluxes and storages across the planet,” said Augusto Getirana, a research scientist at NASA Goddard and a co-author of the paper.
The study results suggest that Earth system models used to simulate the future global water cycle should evolve to integrate the ongoing effects of human activities. With more data and improved models, producers and water resource managers could understand and effectively plan for what the “new normal” of their local water situation looks like, Nie said.
By Erica McNamee
NASA’s Goddard Space Flight Center, Greenbelt, Maryland
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Last Updated Jan 16, 2025 EditorKate D. RamsayerContactKate D. Ramsayerkate.d.ramsayer@nasa.gov Related Terms
Earth Global Precipitation Measurement (GPM) Goddard Space Flight Center Moderate Resolution Imaging Spectroradiometer (MODIS) Water & Energy Cycle Explore More
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By NASA
NASA/Don Pettit On Jan. 10, 2025, NASA astronaut Don Pettit posted two images of the Los Angeles fires from the International Space Station. Multiple destructive fires broke out in the hills of Los Angeles County in early January 2025, fueled by a dry landscape and winds that gusted up to 100 miles per hour.
See satellite imagery of the fires.
Image credit: NASA/Don Pettit
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By NASA
2 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Artist concept highlighting the novel approach proposed by the 2025 NIAC awarded selection of the Thermo-Photo-Catalysis of Water for Crewed Mars Transit Spacecraft Oxygen Supply concept.NASA/Saurabh Vilekar Saurabh Vilekar
Precision Combustion
Precision Combustion, Inc. (PCI) proposes to develop a uniquely compact, lightweight, low-power, and durable Microlith® Thermo-Photo-Catalytic (TPC) Reactor for crewed Mars transit spacecraft O2 supply. As crewed space exploration mission destinations move from low Earth orbit to sustained lunar surface habitation toward Mars exploration, the need becomes more intense to supplant heritage physico-chemical unit operations employed for crewed spacecraft cabin CO2 removal, CO2 reduction, and O2 supply. The primary approach to date has been toward incremental improvement of the heritage, energy intensive process technologies used aboard the International Space Station (ISS), particularly for water electrolysis-based O2 generation. A major breakthrough is necessary to depose these energy intensive process technologies either partly or completely. This is achievable by considering the recent advances in photocatalysis. Applications are emerging for converting CO2 to useful commodity products and generating H2 from atmospheric water vapor. Considering these developments, a low power thermo-photo-catalytic process to replace the heritage high-power water electrolysis process is proposed for application to a Mars transit vehicle life support system (LSS) functional architecture. A key component in realizing this breakthrough is utilizing a catalyst substrate such as Microlith that affords high surface area and promotes mass transport to the catalyst surface. The proposed TPC oxygenator is expected to operate passively to continually renew the O2 content of the cabin atmosphere. The targeted mission for the proposed TPC oxygenator technology deployment is a 2039 Long Stay, Earth-Mars-Earth mission opportunity. This mission as defined by the Moon to Mars (M2M) 2024 review consists of 337.9 days outbound, 348.5 days in Mars vicinity, and 295.8 days return for a total 982.2-day mission. The proposed Microlith oxygenator technology, if successful, is envisioned to replace the OGA technology in the LSS process architecture with significant weight and power savings. In Phase I, we will demonstrate technical feasibility of Microlith TPC for O2 generation, interface requirements, and integration trade space and a clear path towards a prototype demonstration in Phase II will also be described in the final report.
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Last Updated Jan 10, 2025 EditorLoura Hall Related Terms
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By NASA
NASA’s Dawn spacecraft captured this image of Vesta as it left the giant asteroid’s orbit in 2012. The framing camera was looking down at the north pole, which is in the middle of the image.NASA/JPL-Caltech/UCLA/MPS/DLR/IDA Known as flow formations, these channels could be etched on bodies that would seem inhospitable to liquid because they are exposed to the extreme vacuum conditions of space.
Pocked with craters, the surfaces of many celestial bodies in our solar system provide clear evidence of a 4.6-billion-year battering by meteoroids and other space debris. But on some worlds, including the giant asteroid Vesta that NASA’s Dawn mission explored, the surfaces also contain deep channels, or gullies, whose origins are not fully understood.
A prime hypothesis holds that they formed from dry debris flows driven by geophysical processes, such as meteoroid impacts, and changes in temperature due to Sun exposure. A recent NASA-funded study, however, provides some evidence that impacts on Vesta may have triggered a less-obvious geologic process: sudden and brief flows of water that carved gullies and deposited fans of sediment. By using lab equipment to mimic conditions on Vesta, the study, which appeared in Planetary Science Journal, detailed for the first time what the liquid could be made of and how long it would flow before freezing.
Although the existence of frozen brine deposits on Vesta is unconfirmed, scientists have previously hypothesized that meteoroid impacts could have exposed and melted ice that lay under the surface of worlds like Vesta. In that scenario, flows resulting from this process could have etched gullies and other surface features that resemble those on Earth.
To explore potential explanations for deep channels, or gullies, seen on Vesta, scientists used JPL’s Dirty Under-vacuum Simulation Testbed for Icy Environments, or DUSTIE, to simulate conditions on the giant asteroid that would occur after meteoroids strike the surface.NASA/JPL-Caltech But how could airless worlds — celestial bodies without atmospheres and exposed to the intense vacuum of space — host liquids on the surface long enough for them to flow? Such a process would run contrary to the understanding that liquids quickly destabilize in a vacuum, changing to a gas when the pressure drops.
“Not only do impacts trigger a flow of liquid on the surface, the liquids are active long enough to create specific surface features,” said project leader and planetary scientist Jennifer Scully of NASA’s Jet Propulsion Laboratory in Southern California, where the experiments were conducted. “But for how long? Most liquids become unstable quickly on these airless bodies, where the vacuum of space is unyielding.”
The critical component turns out to be sodium chloride — table salt. The experiments found that in conditions like those on Vesta, pure water froze almost instantly, while briny liquids stayed fluid for at least an hour. “That’s long enough to form the flow-associated features identified on Vesta, which were estimated to require up to a half-hour,” said lead author Michael J. Poston of the Southwest Research Institute in San Antonio.
Launched in 2007, the Dawn spacecraft traveled to the main asteroid belt between Mars and Jupiter to orbit Vesta for 14 months and Ceres for almost four years. Before ending in 2018, the mission uncovered evidence that Ceres had been home to a subsurface reservoir of brine and may still be transferring brines from its interior to the surface. The recent research offers insights into processes on Ceres but focuses on Vesta, where ice and salts may produce briny liquid when heated by an impact, scientists said.
Re-creating Vesta
To re-create Vesta-like conditions that would occur after a meteoroid impact, the scientists relied on a test chamber at JPL called the Dirty Under-vacuum Simulation Testbed for Icy Environments, or DUSTIE. By rapidly reducing the air pressure surrounding samples of liquid, they mimicked the environment around fluid that comes to the surface. Exposed to vacuum conditions, pure water froze instantly. But salty fluids hung around longer, continuing to flow before freezing.
The brines they experimented with were a little over an inch (a few centimeters) deep; scientists concluded the flows on Vesta that are yards to tens of yards deep would take even longer to refreeze.
The researchers were also able to re-create the “lids” of frozen material thought to form on brines. Essentially a frozen top layer, the lids stabilize the liquid beneath them, protecting it from being exposed to the vacuum of space — or, in this case the vacuum of the DUSTIE chamber — and helping the liquid flow longer before freezing again.
This phenomenon is similar to how on Earth lava flows farther in lava tubes than when exposed to cool surface temperatures. It also matches up with modeling research conducted around potential mud volcanoes on Mars and volcanoes that may have spewed icy material from volcanoes on Jupiter’s moon Europa.
“Our results contribute to a growing body of work that uses lab experiments to understand how long liquids last on a variety of worlds,” Scully said.
Find more information about NASA’s Dawn mission here:
https://science.nasa.gov/mission/dawn/
News Media Contacts
Gretchen McCartney
Jet Propulsion Laboratory, Pasadena, Calif.
818-287-4115
gretchen.p.mccartney@jpl.nasa.gov
Karen Fox / Molly Wasser
NASA Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov
2024-178
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Last Updated Dec 20, 2024 Related Terms
Dawn Asteroids Ceres Jet Propulsion Laboratory Vesta Explore More
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