USML-2 Public Affairs Status Report #7 6:00 p.m. CDT, Oct. 24, 1995 4/09:07 MET Spacelab Mission Operations Control Marshall Space Flight Center "This mission is a beautiful example of interactive science due to the collaborative efforts between the principal investigators, the cadre and the crew," observed Mission Scientist Marcus Vlasse referring to the second United States Microgravity Laboratory (USML-2) mission. USML-2 scientific investigations continue to operate smoothly and on schedule. Downlink video from the Shuttle on Hi-Pac TV this morning displayed a circular image that appeared to contain a swirling nocturnal snowstorm. This was actually an experiment run of the Surface Tension Driven Convection Experiment which studies thermocapillary flows using aluminum oxide particles suspended in silicone oil illuminated by a laser light. By relaying commands to Payload Commander Kathy Thornton to adjust the temperature parameters on the surface of the liquid, Project Scientist Alex Pline and his science team are able to study the transition from steady fluid flows to more oscillating, or unstable flows, that result when heat is applied to a liquid's surface. Thermocapillary flows are present on Earth in many industrial and materials processing methods, but are difficult to study due to the presence of gravity-driven fluid flows. By conducting this experiment in microgravity, scientists can isolate the thermocapillary flows, gaining insight on how and why they occur. The Astroculture plant growth facility continues to operate smoothly, providing the proper water, humidity and light to the small potato tubers growing within the apparatus. Co- investigator Dr. Ted Tibbitts commented on the progress of the 10 small potatoes. "They look very happy and well, staying very turgid, which means they have not wilted, so the environment is good for them," he said. Downlink video shows only green leaves, since the tubers are buried in the soil. That's the exciting part, Tibbitts said, but something their team won't see until the end of the mission. The potatoes will be studied after the mission to determine the effects microgravity has on starch accumulation in plants. Scientists believe plants will play an important role in long-duration space flights, such as missions on the International Space Station, providing food and water to crews, replenishing oxygen and also helping remove excess carbon dioxide from the air. Investigators also believe plants could provide a psychological lift to astronauts in an otherwise sterile environment. "I think it's beautiful," exclaimed Payload Specialist Al Sacco describing the 1 inch (8 cubic centimeter) drop of water he successfully deployed and released from the Drop Physics Module apparatus this morning. A crew member manipulates the liquid drops using sound waves in order to study their behavior under the influence of external forces. This type of research will help investigators understand science and technology in which liquid drops have a role, from rain formation and weather patterns to chemical processing. Later this week, an experiment known as Science and Technology of Surface-Controlled Phenomena will be conducted with a surfactant added to the water drop. Surfactants, such as soap, reduce the holding power of a liquid surface. These chemicals play an important role in industrial processes, among them the production of cosmetics, the dissolution of proteins in synthetic drug production and the enhancement of oil recovery. Data from these observations should give a better understanding of the molecular forces acting in the surface layer of simple water drops and should provide a better basis for industrial applications. Near the end of the red shift, Pilot Ken Rominger used a camcorder to film a couple of unattended experiment operations starting with the Commercial Generic Bioprocessing Apparatus. This multi-user facility allows a variety of sophisticated bioprocessing experiments to be performed in one piece of hardware. Major areas of focus on USML-2 include biomedical testing and drug development, ecological systems development and biomaterials products and processes. Next Rominger focused his camera on the Crystal Growth by Liquid-Liquid Diffusion apparatus sponsored by the Marshall Space Flight Center in Huntsville, Ala. The experiment consists of four transparent hand-held diffusion test cells, attached to the outside of a Shuttle middeck locker so they are easily seen. In this unique crystal growth facility, proteins and precipitants diffuse into one another by random action of molecules instead of being mixed. Sacco spent about 4 hours this afternoon in the Glovebox facility activating protein crystal growth samples. Later the samples were transferred to a specialized incubator maintained at a prescribed temperature. Proteins play important roles in daily life, from providing nourishment to fighting disease. Because a protein's structure determines its function, researchers seek to grow large, well-ordered crystals for post-mission structural analysis. Crew members on the upcoming 12-hour shift will continue work in the Drop Physics Module and the Surface Tension Driven Convection Experiment. Status reports are issued from Johnson Space CenterŐs Mission Control at 8 a.m. and 5 p.m.; and from Marshall Space Flight CenterŐs Spacelab Mission Operations Control at 6 a.m. and 6 p.m. weekdays, 6 a.m. on weekends. For additional information, see the Internet USML-2 payload homepage, http://liftoff.msfc.nasa.gov/spacelab/usml2/welcome.html and the STS-73 Shuttle homepage, http://shuttle.nasa.gov