Scott Kelly, who marked Day 300 of his nearly year-long mission on the International Space Station on Jan. 21, shows off a feature of life in microgravity.
Kelly used two paddles with hydrophobic, or water repellent, features to pass a sphere of water back and forth.
The paddles are polycarbonate laser etched so that the surfaces are actually arrays of 300 micrometer posts (0.3mm). The surfaces were then spray coated with a Teflon coat. The combined effects of surface roughness and non-wettability produce a super-hydrophobic surface capable of preventing water adhesion in dynamic processes.
The larger the drop, the less force it takes to break it up. The smaller the drop, the harder you can hit it. Scott is demonstrating about a 4 mL drop (over 100 times larger than a rain drop).