A unique application of capillary flow allows workers aboard the International Space Station (ISS) to sip their coffee as easily as they would back on Earth. Designed by NASA astronaut Don Pettit, the cup makes use of a narrow, angled channel to draw liquid up by capillary action. This wetting effect is also unhampered by gravity on the ISS, allowing for a satisfying and uninterrupted drink.
Although it seems like just a bit of fun, the technology is already in use for fluid transport in weightless environments, such as in fuel tanks for rockets, micro-gravity condensing heat exchangers and multiphase fluid control. The unique behaviour of fluids in microgravity is especially relevant to our own research at the Micro & Nano Flows group and hopefully in time we will see many more interesting devices driven by unconventional fluid effects.
For those interested, a replica cup is available if you wish to drink like an astronaut, although with the addition of a stable, flat base for when gravity gets you down.