At the Dusty Plasma Laboratory at NASAs Marshall Space Flight Center the conditions of space are simulated so scientists can understand what is happening in the rings of Saturn, the atmosphere of Titan and what we think of as a vacuum between stars.

"What we're doing here is taking one particle and exposing it to these space-like environments and studying what happens to its [electrical] charge and other properties," said Catherine Venturini, a graduate student at the University of Alabama in Huntsville.

The centerpiece of the lab is a small vacuum chamber with electrodes to suspend particles using static electricity, the same effect that makes your hair stand on end after rubbing a balloon across your head. The chamber itself is about the size of a coffee mug. The entire system sits atop a large lab bench.

In space, electrical charges, magnetic fields and light pressure probably have greater influence over dust particles than gravity alone. (Static charging is why dust flies to and sticks on your TV screen or computer monitor. While household dust is made of dead skin cells and other organic debris, the principle is the same.)

These forces may make cosmic dust stick together or fly apart, or even fly in formation to form the mysterious dark spokes that Voyager saw moving across the face of Saturns rings. Whatever controls dust also helps determine how and when it condenses into planets and moons.

~

Surprisingly, even so simple an item as dust warrants a series of experimental steps that study one tiny aspect at a time.

"At present, the lab is set up to do charge processing of dust particles," said Dr. Mian Abbas, a lead scientist on the Dusty Plasma Laboratory. He is looking at how dust particles acquire and retain -- or shed -- electrical charges. Abbas and Venturini are also measuring how dust grains emit light in order to understand better what is observed in astronomical images of dust-filled regions of deep space.

Initial experiments with the lab used microscopic grains of salt, left behind when saltwater droplets evaporated as the chamber was pumped down to a vacuum. Salt crystals are not common in space, but this step allowed Dr. James Spann, the lab developer (now assigned to NASA Headquarters), Abbas and Venturini to calibrate the lab equipment.

Abbas is now using microspheres of aluminum oxide and plastic.

"We know what those particles properties are very accurately," he said. "These preliminary experiments have been to determine the usefulness of the facility." It has also generated interest in the scientific community that has given "very supportive" responses following three presentations on the facility.

So how do you charge a dust grain? The same way it happens in space. Abbas explained that the Dusty Plasma Lab has two mechanisms -- an electron gun and an ultraviolet lamp. The electron gun can bombard the dust grains directly with electrons and build a charge. Or, ultraviolet light can knock electrons off the grains surface and thus build a charge. (The same thing happens to satellites exposed to sunlight.)

Thats not all there is to the space environment. Abbas hopes to get funding to expand the lab to go beyond the room-temperature range that we humans like. An infrared diode could heat dust grains to simulate conditions near a star. And a cryogenic cooling system could simulate conditions in interstellar space, where temperatures plunge as low as minus 405 degrees Fahrenheit (minus 233 Celsius; 30 degrees Kelvin), or in the atmosphere of Titan, where its a toasty minus 315 degrees Fahrenheit (minus 193 degrees Celsius; 80 degrees Kelvin).

In the latter case, "We will focus on nucleating cold dust particles, by injecting water or methane, and investigate how particles grow with condensation of various gases," as inside Titans methane atmosphere, Abbas explained.

The advance work will also start using materials more like interstellar dust, including silicates, carbonaceous chondrites, and metal flecks coated with other materials.

"It's another facet to understanding the whole picture," said Venturini. "You have the modeling; you've got the theory; you've got the observation from satellites [such as Galileo and Cassini] and then you need the lab work to help verify the other components." Because of data from deep-space probes, scientists are realizing, "'Hey, these little dust particles are playing a much more important role than we thought before."