Science gets a start on the space station - Brief Article

Science News, Nov 11, 2000 by R. Cowen

At a crowded press conference in Russia late last month, the stars of the show--cosmonauts Yuri Gidzenko and Sergei Krikalev, along with astronaut William Shepherd--sat behind a glass enclosure. The trio, then under quarantine in preparation for their Nov. 2 flight to the International Space Station (ISS), became the first crew to inhabit the Tinkertoy-like structure still under assembly in orbit around Earth.

Attending the briefing was materials scientist Gregor E. Morfill of the Max Planck Institute for Extraterrestrial Physics in Garching, Germany. Afterward, a Russian official invited him and his colleagues into the glass-enclosed area. Soon, they were drinking champagne with the crew and toasting the future success of the mission--and of Morfill's experiment, which is set to become the first physics investigation on board the $100 billion outpost.

The space station's main laboratories have yet to be launched, but researchers are exploiting nooks and crannies already available. For example, in an airlock between two Russian modules of the ISS, the crew will soon begin studies of an unusual type of plasma--a highly ionized gas--formulated by Morfill's team.

Plasmas are normally nature's most disordered form of matter. Morfill's team, however, laced a plasma with microspheres of melanine formaldehyde, which weigh up to 1 trillion times as much as the plasma's individual electrons and ions. The plasma particles glom onto the microspheres, which become electrically charged. By electrically interacting, the microspheres then take on an orderly, crystallike formation.

The microspheres dramatically slow the response of the system to outside stimuli, such as electrical fields. This allows physicists to track the behavior of each microsphere, which is akin to observing the individual ions.

In ground-based experiments, the microsphere layers sink unless researchers apply a strong electric field to counterbalance gravity. But that electric field can confound results, notes Morfill. The researchers turned to the space station to conduct long-duration tests in a low-gravity environment.

Adding microspheres to bring order to other types of unstructured material could lead to "a new technology for making designer materials," Morfill says.

Morfill's plasma experiments are slated to begin early next year, but biotechnology studies are already under-way. They are examining more-traditional types of crystal--protein and DNA crystals grown in supersaturated solutions. In low gravity, diffusion in a liquid occurs slowly, and crystals can grow in a more precise pattern, says Craig Kundrot of NASA's Marshall Flight Center in Huntsville, Ala.

A more orderly crystal would enable X-ray crystallographers to probe a compound's structure with unprecedented precision. Such analysis could fine-tune the development of drugs designed to bind to or target those biological molecules, he says.

With the scheduled launch of a U.S.--made science module in February and the arrival of a materials science laboratory in 2002, larger-scale, more power-intensive experiments will begin on the space station. For example, Frank Szofran of Marshall and his colleagues plan to study different ways of making crystals of germanium silicon. This alloy, if it can be grown with few defects, could be used to make more efficient solar cells and better optics to focus X rays, he says.