The Zero Gravity Coffee Cup   
       
   July 15, 2013:  High above our planet in the realm of satellites and space   
   stations, the familiar rules of Earth do not apply. The midday sky is as black   
   as night. There is no up and no down. Dropped objects do not fall, and hot air   
   does not rise.   
       
   Of all the strange things that happen up there, however, it is possible that   
   the strangest happens to coffee.   
       
   http://www.youtube.com/watch?v=nZYsOG60dKQ   
       
   A new ScienceCast video describes the strange behavior of coffee in   
   microgravity. Play it   
       
   Physics professor Mark Weislogel of Portland State University has given a lot   
   of thought to coffee (and other fluids) in space, and he describes what   
   happens:   
       
   "For starters," he says, "it would be a chore just getting the coffee into the   
   cup. Absent the pull of gravity, pouring liquids can be very tricky."   
       
   "But, for the sake of argument, let's suppose you are on the space station and   
   you have a cup of coffee in your hand."  The most natural thing would be to   
   tip the cup toward your lips, but when you do..   
       
   "The coffee would be very hard to control," he continues. "In fact, it   
   probably wouldn't [come out of the cup].  You'd have to shake the cup toward   
   your face and hope that some of the hot liquid breaks loose and floats toward   
   your mouth."   
       
   http://www.nasa.gov/mission_pages/station/research/experiments/459.html   
       
   Astronaut Cady Coleman performs a Capillary Flow Experiment interior corner   
   flow test. moreOn the bright side, you will probably be wide awake by the time   
   the cup is empty.   
       
   Coffee is not the only liquid that misbehaves in space. Cryogenic fuels,   
   thermal coolants, potable water and urine do it, too. The behavior of fluids   
   is one of the most un-intuitive things in all of space flight.   
       
   This poses an extreme challenge for engineers designing spacecraft systems   
   that use fluids. "Our intuition is all wrong," laments Weislogel.  "When it   
   comes to guessing what fluids will do in new systems, we are often in the   
   dark."   
       
   To develop a better understanding of fluids in microgravity, Weislogel and   
   colleagues are conducting the Capillary Flow Experiment onboard the   
   International Space Station. For instance, one of the devices in their   
   experiment suite looks at "interior corners."  If two solid surfaces meet at a   
   narrow-enough angle, fluids in microgravity naturally flow along the join-no   
   pumping required.  This capillary effect could be used to guide all kinds of   
   fluids through spacecraft, from cryogenic fuel to recycled waste water. The   
   phenomenon is difficult to study on Earth, where it is damped by gravity, yet   
   on the space station large scale corner flows are easy to create and observe.   
       
   http://www.youtube.com/watch?v=pk7LcugO3zg   
       
   Don Pettit drinks from a zero-G coffee cup. Youtube video   
       
   Weislogel and colleagues have already been granted three patents for devices   
   invented as a result of their work. One is for a microgravity condensing heat   
   exchanger. Another describes a device that separates and controls multiphase   
   fluids. The third patent is for--you guessed it-- a low-gravity coffee cup.   
       
   Astronaut Don Pettit, who worked with the Capillary Flow Experiment during his   
   time on board the ISS, helped invent the cup, and he shares the patent along   
   with Weisogel and two mathematicians, Paul Concus and Robert Finns, who   
   performed the first theoretical analysis of the phenomenon.   
       
   Basically, one side of the cup has a sharp interior corner.  In the   
   microgravity environment of the space station, capillary forces send fluid   
   flowing along the channel right into the lips of the drinker.   
       
   "As you sip, more fluid keeps coming, and you can enjoy your coffee in a   
   weightless environment-- clear down to the last drop," says Pettit. "This may   
   well be what future space colonists use when they want to have a   
   celebration."  Indeed, the patent application specifically mentions "toasting"   
   as one of the uses of the device.   
       
   It's easy to imagine what they might be toasting: toilets and air conditioners   
   and fuel tanks and recycling systems, working better thanks to capillary flow   
   experiments on the ISS.   
       
   Credits:   
       
   Author:Dr. Tony Phillips| Production editor: Dr. Tony Phillips | Credit:   
   Science@NASA   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.94   
    * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)