☕🚀 “Drinking in microgravity? Let’s talk capillary geometry.” In the microgravity environment aboard the International Space Station (ISS), conventional contact-with-liquid dynamics break down: without gravity to pull the fluid into the lip of a cup, liquids behave as floating blobs, prone to detachment and uncontrolled drift.  To solve this, astronaut Pettit employed the principle of capillary channel flow: a precisely folded sheet forming a teardrop-shaped cavity with a narrow channel along one edge. Surface-tension forces draw the liquid from the base toward the rim when you bring the lip of the cup to your mouth.  Key technical features: • The fold angle and contact-wetting geometry are selected to support spontaneous liquid transport in microgravity (i.e., without gravitational sag).  • Materials were initially simple (Mylar sheet, Kapton tape) for prototyping aboard the ISS.  • Subsequent versions used 3-D printed food-grade plastic and ceramic materials, enabling durab...