WALLOPS ISLAND (VA), October 27, 2022 – As climate change-driven wildfires worsen, havoc wrecked by post-wildfire mudslides is a growing danger. These gravity-driven mudflows happen suddenly and are difficult to predict. They can have devastating effects, including lost lives, destroyed homes, and damaged infrastructure. Knowing the causes of mudslides is critical to improving predictions that save lives and reduce damage. To better understand gravity’s effects on post-wildfire mudflow, a research team from the University of California, San Diego (UC San Diego) will take their research to the only laboratory where gravity is removed—the International Space Station (ISS).
The project, funded by the U.S. National Science Foundation and supported by ISS National Laboratory Commercial Service Provider Space Tango, will study the hydrodynamics of mudslides. The results could lead to improved mudflow models, new critical infrastructure, and the development of early-warning systems. Through the investigation, which is launching on Northrop Grumman’s upcoming 18th Commercial Resupply Services mission (NG-18), the research team will test a new paradigm for explaining how mudflows are triggered in post-wildfire environments. While it is well-established that burnt organic matter produces gases that create water-repellent (hydrophobic) soil particles, the team hypothesizes that this soil entraps air. Mudflow, they argue, results from the mixture of rainwater and air with hydrophobic soil particles.
“When particles, air, and water mix in post-wildfire soil, it becomes a foam-like consistency that is heavily affected by gravity, which forces it down mountains,” said Ingrid Tomac, assistant professor of geomechanics and geotechnical engineering in the department of Structural Engineering at UC San Diego. “By taking gravity away, we may better understand the role gravity plays in mudslides on Earth.”
The automated experiment will allow the team to examine the mixing, flow, and transport of hydrophobic particles (non-wettable sand that is similar to the water-repellent soil that wildfires create) in mixtures of air and water. The experiment will use different-sized sand particles to closely reproduce field soil conditions and will test how mixtures behave when they flow at different speeds. By observing how these components behave in microgravity, researchers can better understand gravity’s role in mudflows back on Earth. Data will be used to study what Tomac calls “the missing link” between known materials that form mudflows and the poorly understood fluid forces of mudslides. This investigation could help researchers create better models to predict mudflow.
“Civil engineering is often synonymous with buildings and cities, but it’s also about soil,” Tomac said. “To predict mudslides, we need to understand the soil mechanics of mudslides in post-wildfire environments.”
This is just one of more than 20 ISS National Lab-sponsored payloads on NG-18, which is set to launch from Wallops Flight Facility no earlier than November 6 at 5:50 a.m. EDT. Please visit our launch page to learn more about all ISS National Lab-sponsored research.
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About the International Space Station (ISS) National Laboratory: The International Space Station (ISS) is a one-of-a-kind laboratory that enables research and technology development not possible on Earth. As a public service enterprise, the ISS National Lab allows researchers to leverage this multiuser facility to improve life on Earth, mature space-based business models, advance science literacy in the future workforce, and expand a sustainable and scalable market in low Earth orbit. Through this orbiting national laboratory, research resources on the ISS are available to support non-NASA science, technology, and education initiatives from U.S. government agencies, academic institutions, and the private sector. The Center for the Advancement of Science in Space, Inc. (CASIS) manages the ISS National Lab, under Cooperative Agreement with NASA, facilitating access to its permanent microgravity research environment, a powerful vantage point in low Earth orbit, and the extreme and varied conditions of space. To learn more about the ISS National Lab, visit www.ISSNationalLab.org.
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