"Saturday is when we have a bit of free time," said Pettit, the NASA International Space Station Science Officer on the Expedition Six crew. While some of the crew read books, play musical instruments or watch movies, "I prefer to do 'Saturday Morning Science' fun experiments of my own design," Pettit said.
One recent Saturday aboard the International Space Station, Pettit prepared a solution of water, soap and glycerin, and fashioned a bubble-wand from thin wire. "I wanted to see what thin films and bubbles might do in zero gravity and felt it was a topic ripe for discovery," he said.
Next, Pettit injected some tiny mica flakes into the film, allowing him to observe otherwise-hidden flows and swirls. "Then I blew on the film, and fascinating patterns emerged. These tracer particle patterns lasted for well over four hours, he said."
These films highlight the value of space for fundamental science research in fluid physics. Gravity-driven convection and three-dimensional motions complicate fluid flow on Earth, but not aboard the International Space Station. A two-dimensional film of weightless water is a splendid research tool that could yield valuable data for many industries on Earth.
Pettit has also taken still pictures of cities at night from the International Space Station, obtaining very high-resolution images, and observed noctilucent or "night-shining" clouds, rare and not fully understood atmospheric science phenomena. "Over the past few weeks we've been enjoying outstanding views of these clouds above the southern hemisphere," Pettit remarked during a NASA TV broadcast.
Pettit is a long-time noctilucent cloud-watcher. As a staff scientist at the Los Alamos, N.M. National Laboratory between 1984 and 1996, he studied noctilucent clouds that were seeded by high-flying sounding rockets. "Seeing these kinds of clouds [from the Space Station] ... is certainly a joy for us on the Space Station," he said. Pettit intends to continue his Saturday Science activities until his return home from the International Space Station in early May.
"Observations of nature, no matter how seemingly arcane, are like peeling off one more layer from the great onion of knowledge, tickling your imagination with what you have found but always revealing yet another tantalizing layer underneath," Pettit said. "I hope we never get to the core."
Pettit's International Space Station Saturday Science videos and written observations are available on the Internet at: http://spaceflight.nasa.gov/station/crew/exp6/spacechronicles.html
