How do astronauts drink water in zero gravity? The science behind this 'magical' NASA cup will blow your mind

New Delhi (The Uttam Hindu): Space is a microgravity environment. The gravity is so low that water or any liquid doesn't fall, but instead forms a ball or floats around. For astronauts living on the International Space Station (ISS), drinking water from a regular cup is impossible because the liquid would spill and evaporate.

Previously, astronauts used plastic pouches to drink water. The pouches were filled with liquid, attached to a tube or nozzle, and they would suck on the liquid. This method was safe, but quite uncomfortable. Astronauts also couldn't get a proper taste or aroma of coffee or tea.

The US space agency NASA has ingeniously found a solution to this problem. NASA astronaut Don Pettit invented a special "Zero-G Cup," or space cup, for drinking in microgravity. This cup gives astronauts a similar Earth-like drinking experience—sipping directly from the cup without a straw.

Astronauts explain what a Zero-G Cup is and how it works. A Zero-G Cup is a small, specially shaped container made of plastic, slightly larger than a trading card. The cup is designed like a teardrop, with a narrow channel or groove on the inside that has a sharp edge. In microgravity, surface tension and capillary action operate instead of gravity. When water is poured into the cup, it sticks to the bottom. Due to the narrow walls and channel, the water rises upwards due to surface tension. This water reaches the edge of the cup, where it can be easily sipped.

When you lift the cup to your lips and sip normally, the liquid automatically flows to the edge. After taking a sip, the surface tension balance is disturbed, and more water from the bottom rises into the channel. This way, all the liquid can be consumed without wasting it. The cup is also non-spillable, meaning that the liquid won't spill out during normal movements.

Don Pettit designed the prototype of this cup while aboard the ISS. NASA later refined it. This design is based on the laws of physics, specifically capillary flow. Astronauts can now enjoy the comfortable experience of sipping coffee, tea, or water from a cup while inhaling its aroma. The Zero-G Cup not only enhances convenience but also benefits astronauts' mental health.