Liquid nitrogen spray to clean spacesuits
Researchers from Washington State University developed a liquid nitrogen spray to remove moon dust from a space suit, potentially solving what is a significant challenge for future moon-landing astronauts.
Moon dust, scientifically known as lunar regolith, presents significant challenges for lunar activity. It is comprised of electrically charged, sharp, and irregular dust particles that cause harm to human health and equipment.  The abrasive and tiny dust particles can get into engines and electronics. They also get into the spacesuits, destroying their seals and making some of the expensive suits unusable. Furthermore, researchers think that prolonged exposure to the dust could cause lung damage in astronauts. 
The NASA Artemis mission aims to return astronauts to the lunar surface by 2025, with the hope of eventually setting up a base camp there for further planetary exploration. It is therefore important for NASA to find a solution to the moon dust problem. Traditional spacesuit cleaning methods, such as brushing and vacuuming, have limited effectiveness and introduce suit fabric abrasion. Dust removal with traditional fluids, gels, gases, and non-cryogenic liquids, while sometimes effective, has been deemed ineffective for lunar application. 
Supported by a NASA grant, a team of researchers from the Washington State University reported 98.4% mass removal by impinging specimens with liquid nitrogen sprays measured at different spray angles in a vacuum chamber. While a brush caused damage to the spacesuit material after just one stroke, the liquid nitrogen spray took 75 cycles before damage occurred. [1, 2]
Their technology uses the Leidenfrost Effect to clean the space suits. This effect can be seen when cold water is poured onto a hot frying pan, where it beads up and moves across the pan. Spray the very cold liquid nitrogen at a warmer dust-covered material, and the dust particles bead up and float away on the nitrogen vapour. 
The researchers are now working to fully understand and model the complex interactions between the dust particles and the liquid nitrogen that allows the cleaning process to work. They are also applying for another grant to further test the technology in conditions closer to outer space, such as lunar gravity. 
Documents on space applications for refrigeration technologies are available on FRIDOC.
Impact of operating parameters on 80 K pulse tube cryocoolers for space applications
NASA Glenn Research Center Creek Road Cryogenic Complex: Testing between 2005–2019
 Wells, I., Bussey, J., Swets, N., & Leachman, J. (2023). Lunar dust removal and material degradation from liquid nitrogen sprays. Acta Astronautica. https://doi.org/10.1016/j.actaastro.2023.02.016
 Tina Hilding. WSU Insider. 28 February 2023. https://news.wsu.edu/press-release/2023/02/28/liquid-nitrogen-spray-could-clean-up-stubborn-moon-dust/
image credits: Astronaut Buzz Aldrin on the moon @Wikimedia Commons