Station Science Top News: Jan. 19, 2023

Researchers found that antifreeze glycoprotein (AFGP) both slows down and speeds up ice crystal growth in supercooled water in microgravity, despite holding all conditions stable. The effects of AFGP have not been successfully demonstrated on Earth because ice crystal formation is likely also affected by gravity. These results advance the fundamental understanding of how biological molecules can affect crystal growth.

These observations from JAXA’s Ice Crystal 2 study suggest that AFGP, which has been found in fish living in Earth’s polar regions, plays a dual and paradoxical role in inhibiting and stimulating ice crystal growth. Researchers proposed a new theoretical model for what causes this based on AFGP gradually embedding in the crystals as they are formed and how fast the surface of the crystal is renewed.

These types of fundamental scientific studies benefit society by expanding our knowledge base and leading to breakthroughs that often have an unexpected long-term application. This includes solutions to global problems such as infectious diseases and climate change.

Expedition 39 commander and Japan Aerospace Exploration Agency (JAXA) astronaut Koichi Wakata is photographed with Ice Cell 2 during preparations for its installation into the Solution Crystallization Observation Facility (SCOF) in the Kibo Japanese Experiment Pressurized Module (JPM). The Ice Crystal 2 investigation examines the growth rates and stability of ice crystals in supercooled water that contains antifreeze glycoprotein (AFGP). Credits: NASA

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Using both parabolic flight and space station data, researchers measured the surface tension and viscosity of liquid germanium to better understand the melting process. Germanium is a common semiconductor material, so a more accurate measurement of its properties could benefit numerous industries that take advantage of cutting-edge electronics.

The containerless environment of the electromagnetic levitator (EML) aboard station helped researchers from ESA’s EML Batch 2 – SEMITHERM study obtain observations that are difficult to make under the forces of gravity. They measured properties of the liquid over a range of temperatures by applying an electromagnetic force field to excite surface oscillations in the sample. Results indicated thicker sample viscosity during parabolic flights than in the EML facility, but models reveal that this observed difference was caused by turbulent flow observed in the EML samples during testing.