During Dr. Donald Pettit's nearly six-month flight (from November 2002 – May 2003) on-board the International Space Station, he conducted many experiments and demonstrations for the Saturday Morning Science Program. His “Symphony of Spheres” is an excellent illustration of the fluid physics experiments that can be performed in microgravity, as opposed to a 1-g, low-gravity environment. Don's comments about his “Symphony of Spheres” included:
“Created inside the air bubble were a half-dozen or so small spherical droplets of water, one to four millimeters in diameter, orbiting around like a miniature solar system. … This motion appeared almost life-like so that for a minute I thought we were looking through a magnifier at some new form of creatures zooming around inside of a three-dimensional Petri dish. … Of all the things on orbit I have seen to date, this is by far the most amazing.”
Drop coalescence is so strongly hindered by the absence of gravity that it poses a unique challenge for engineers designing fluids handling equipment for spacecraft.
