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Release: Feb. 23, 2001

UI researcher prepares first experiment conducted on International Space Station

IOWA CITY, Iowa -- When the first crew of the International Space Station personnel conducts its first physical science experiment on March 3, 6 and 7, the University of Iowa will be represented.

That's because UI physics and astronomy professor John Goree is a co-investigator for the Plasma Crystal Experiment (PKE), an investigation being conducted in collaboration with German and Russian researchers.

Scheduled for a Feb. 25 launch and transport to the space station aboard a Russian unmanned Progress rocket, PKE is basic research aimed at using a low gravity environment to better understand the structure of matter. The experiment's hardware is contained in two boxes, one cylindrical in shape and a little larger than an office trash can and the other resembling a desk drawer.

"We will begin with a plasma, or electrically charged gas, into which we will introduce plastic microspheres about 10 microns in diameter, smaller than the diameter of a human hair," Goree says. "The microspheres will disperse in the plasma and become similarly electrically charged. They will repel one another so that they arrange themselves in a fixed spacing, like the atoms in a crystalline lattice such as ice, sugar or diamonds."

Under Earth-bound laboratory conditions, gravity causes sedimentation of the particles, resulting in a thin horizontal layer at the bottom of the plasma. The particles in the microgravity of the International Space Station will be imaged with a camera and laser illumination so that particles in the suspension can be viewed and their positions and velocities recorded.

Goree notes that in one sense, he is imitating nature because the PKE experiment's so-called "dusty plasmas," in which plasmas contain small particles of solid matter, exist naturally in the rings of Saturn and the tails of comets.

Goree's work on the Plasma Crystal Experiment is funded by a $459,000 NASA Microgravity Program grant that runs from January 1, 1998 through December 31, 2002. His colleagues include Principal Investigator Gregor Morfill, professor at the Max Planck Institute for Extraterrestrial Physics, Garching, Germany; and Principal Investigator Vladimir Fortov of the High Energy Density Research Center, Moscow and vice president of the Russian Academy of Sciences.