Magnetic Levitation-based Low-gravity Simulator promises 1,000 times the volume


November 19, 2021. By Kolemann Lutz


Researchers from FAMU-FSU built a Magnetic Levitation Simulator (MLS) by generating a 24-T superconducting magnet with four Maxwell coils made of REBCO tape that can exceed 20,000 μL or 20 cm³ (1 in³) sample size volume at the gravity of Mars. MLS holds the potential to break new ground in evaluating the short term effects of reduced gravity on biology, cells, and smaller sample sizes to better adapt systems and life to thrive beyond Earth.


The low gravity environment on nearby planetary bodies affects biological systems, fluid dynamics, heat transfers, and how materials form and grow. This can cause many challenges to establishing colonies on the Moon or Mars, which suggests a need to prioritize and correlates well with the boom in low-gravity studies in recent years.


In 1997, researchers in the Netherlands and England used a strong 16 tesla (160,000 Gauss) superconducting magnets to make frogs levitate in a strong magnetic field. As the resulting object is in a net zero field, the MLS magnetic field can be used to quantify the effects of reduced gravity on biological and nonbiological materials on planetary surfaces.

Magnetic Levitation-based Simulators (MLS) can provide many advantages over existing systems (centrifuges and in-orbit experiments) including adjustable gravity low cost, easy accessibility, and unlimited operation time. MLS can replicate as low as 1% of Earth's 1G at low cost for indefinite time. However, with current technology the volume is limited to only a few microliters.


Researchers from FAMU-FSU College of Engineering and the and the FSU-headquartered National High Magnetic Field Laboratory built an MLS by using 8cm diameter high-temperature superconducting (HTS) Maxwell coil, to produce a magnetic field with a large volume of 4,000 microliters at a constant gradient for minimal energy. If set to the gravity of Mars (1 gM = 0.38 gE), the MLS volume expands to 20 cm³ (1 in³), or a or a box with the length of 2.7 cm on each side (1 inch per side).


"Our MLS design offers a functional volume about three orders of magnitude larger than that for conventional solenoid MLSs makes it a potential game-changer in the low-gravity research field," says Wei Guo, associate professor in mechanical engineering and lead scientist on the study. "When this MLS design is used to emulate reduced gravities in extraterrestrial environments, such as on the Moon or Mars, the resulting functional volume is large enough to accommodate even small plants, making this an exciting tool for medical and biology research."


To induce the 24-tesla magnetic field, four sets of gradient-field Maxwell coils with 94 turns of REBCO (Rare-earth barium copper oxide) high temperature superconducting tape for zero electrical resistance, were positioned in the bore of the superconducting solenoid magnet with a bore diameter of 12 cm (4.7 inches).

Fig. Volume analysis for a 24-T MLS setup.

As the superconducting magnet was cooled by immersion in a liquid helium bath, the compact REBCO coils can be easily cooled with a 4-K pulse-tube cryocooler inside a shielded vacuum housing.


Considering long term exposure of ultra high magnetic fields typically bring negative health effects to humans and biology, further research is necessary to evaluate the potential long term health effects.


Magnetic Levitation-based Simulators (MLS) hold the potential to be an effective method to break new ground in evaluating the short term effects of reduced gravity on cells, tissues, and smaller sample sizes to better adapt systems and life to thrive on Moon, Mars, and beyond.

 

Sanavandi, H., Guo, W. A magnetic levitation based low-gravity simulator with an unprecedented large functional volume. npj Microgravity 7, 40 (2021). https://doi.org/10.1038/s41526-021-00174-4


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