Calcium Oxalate Crystal Yield in Various Gravity Environments

An experimental chamber and hand-manipulated syringe apparatus were designed, tested, and utilized to assess calcium oxalate crystal yield in Terrestrial-g (1 g), micro-g (0.01 g), Lunar-g (0.16 g), and Martian-g (0.38 g). Aqueous solutions of calcium chloride (100 mM) and oxalic acid (200 mM) were mixed to precipitate calcium oxalate crystals. Gravitational differences were hypothesized to result in differences in the yield of crystal formation. These data are essential for efforts to better understand the correlation between calcium oxalate crystal formation and the production of kidney stones often associated with long-term space missions. The analyses of crystal formation produced in the micro-g (≅0.01 g) conditions of this study suggest that calcium oxalate monohydrate formation yield is slightly greater than those produced in Terrestrial-g conditions.