Submitted by Eric Daniel
Ok, here's the situation. You're a coffee junkie who happens to be a NASA astronaut, not to mention having a doctorate in chemical engineering, trapped in a weightless environment where the lack of gravity makes it impossible to enjoy that mandatory cup of joe in the morning.
Solution? Fabricate yourself a zero-g coffee cup out of a piece of overhead plastic from your handy dandy shuttle flight data file book, which is exactly what NASA astronaut and engineer Dr. Donald Pettit did.
The problem in space is that, with a lack of gravity, there's no way to draw the liquid out of the cup (if you think about it, one normally brings the cup up to the mouth and tilts it to either "pour" the liquid into the mouth, or in the case of hot fluids, such as coffee, bring the surface of the liquid close to the mouth where it can be sipped.) In space, no matter how you tilt the cup, the liquid is not coming out. This is why astronauts have traditionally consumed fluids from pouches, using straws to draw the liquid out.
Well, Dr. Pettit, having worked with Los Alamos labs on a variety of experiments, including reduced gravity fluid flow and problems in detonation physics (yes, he's a rocket scientist) applied the same technological concepts to his coffee cup design that rocket designers do to their zero-g fuel tanks. Zero-g fuel tanks are shaped like a traditional aircraft wing (airfoil), with a large rounded edge (the leading edge) and a sharp angle on the other (trailing) edge. As Dr. Pettit explains in this video, "If the angle (of the trailing edge of the airfoil "cup") is less than 2 x (90-contact wetting angle), then the fluid will be drawn up out of the coffee ( by wicking action created by the interaction between the fluid and the angled surface of the cup.) This will allow you to sip, not suck, a fluid out of the cup as the wicking action will continue to draw more fluid up from the bottom of the cup.
Granted, this little discovery isn't on the same order of criticality as the "Franken-filter" NASA engineers had to come up with for the lithium hydroxide CO2 scrubbers on the Apollo 13 lunar module, but it's still pretty slick.
