07.06.97

Sunday, July 6, 1997, 7:00 a.m. CDTSTATUS REPORT: STS-94-08s

STS-94 MISSION SCIENCE REPORT # 08S



The Microgravity Science Laboratory mission is paying off for crew 
members and science teams which have spent years preparing for their 
mission on the Space Shuttle and this opportunity to conduct 
fundamental scientific research in space. Experiments are yielding 
new information in the areas of biotechnology, combustion science, 
materials science and fluid physics, and researchers are hopeful 
their findings will find applications for improving life on Earth and 
the future of research in space.



Results from the first runs in a study of the capillary-driven heat 
transfer devices, conducted overnight in the Middeck Glovebox aboard 
Spacelab, are shedding new light on how these devices work. The 
experiment is examining their use to transfer heat away from a 
particular location. For instance, in spacecraft they may be used to 
transfer heat from electrical devices to radiators. They weigh less 
than conventional devices because they operate on evaporation and 
condensation, and because they do not require power, they are more 
economical, but there have been problems with their application for 
spacecraft systems.



Payload Specialist Dr. Roger Crouch conducted the first experiment run 
Saturday evening, and Mission Specialist Dr. Donald Thomas completed 
another run early this morning. During the experiment, when heat was 
added to the evaporator, it dried out. “That’s what we 
expected, but for another reason,” said principal investigator 
Dr. Kevin Hallinan of the University of Dayton in Dayton, Ohio. 
“We’re losing liquid. It’s condensing, but not in 
the condenser. The nice thing is we didn’t expect this. It 
offers insight into potential failure mechanisms that may not have 
been considered before. And we’re modifying our procedures to 
look at this failure mechanism as well as the one we 
anticipated.”



Over the last 24 hours, two series of burning fuel droplet runs were 
completed in the Droplet Combustion Apparatus. Payload Specialist Dr. 
Gregory Linteris completed one series Saturday morning, and Crouch 
completed another series in the afternoon. During the experiment, a 
heptane fuel droplet is burned in an atmosphere of helium and oxygen. 
The droplet is formed and deployed in the apparatus. Igniter wires 
are touched to each side of the droplet and then retracted to create 
a free burning droplet. Researchers are gathering information on the 
burning rates of flames, flame structures and conditions under which 
flames are extinguished. Findings from this study will provide a 
better understanding of the combustion process and may lead to 
cleaner and safer ways to burn fossil fuels as well as more efficient 
methods of generating heat and power on Earth.



Yesterday, Thomas powered up the Middeck Glovebox to conduct a study 
of the manipulation of bubble shape and bubble movement in water 
under weightlessness conditions. Many industrial processes, including 
solidification of metallic alloys, are adversely affected by bubbles. 
Findings from this investigation may improve materials processing 
techniques on Earth by eliminating or counteracting bubbles.



Linteris conducted a run of the Laminar Soot Processes experiment in 
the Combustion Module Saturday afternoon, and Payload Commander Dr. 
Janice Voss completed another run last night, giving up her free time 
to do so. During the runs, ethylene fuel was burned in the facility. 
Researchers are gathering information on flame shape, the type and 
amount of soot produced under various conditions and the temperature 
of soot components. Findings from this investigation may lead to a 
better understanding of how to contain unwanted fires, burn fuels 
more efficiently and reduce pollutants.



In the area of materials science, experiments are under way in the 
TEMPUS and Large Isothermal Furnace facilities. These investigations 
may find direct applications in improving techniques used on Earth to 
manufacture materials and in turn lead to better, higher-quality 
products.



In the TEMPUS facility, Thomas activated an experiment to measure the 
heat of undercooled liquid metals. Undercooling occurs when a solid 
is melted into a liquid then cooled below its normal freezing point 
without solidifying. The study, led by Dr. Hans Fecht of the 
Technical University Berlin in Germany, is aimed at determining the 
ability of certain zirconium-based alloys to form glass. Zirconium is 
a metallic element used chiefly in ceramic and refractory compounds 
as alloying agent.



“This is the first time that these particular alloys could be 
prepared and measured in this way,” said Fecht. 
“Undercooling to 200 degrees Celsius is a lot. We have 
excellent and very important data. We’re very excited.”



Early Sunday, Linteris activated the sample in the TEMPUS facility to 
begin another study of glass-forming metallic alloys. This research, 
led by Dr. W.I. Johnson of the California Institute of Technology in 
Pasadena, examines the thermophysical properties -- heat capacity, 
thermal conductivity, nucleation rates, surface tension, viscosity 
and thermal expansion -- of multi-component zirconium-based alloys.



“We are taking fundamental measurements of these alloys, in some 
cases for the first time,” said project scientist Dr. Jan 
Rogers of NASA’s Marshall Space Flight Center in Huntsville, 
Ala. “These measurements will be used to make better products 
on Earth. For instance, findings from metallic glass investigations 
may be used to improve sporting good products, such as golf clubs, 
because of their good elastic properties.”



Science operations in TEMPUS have continued successfully despite 
difficulties with the facility’s top-view video camera. The 
science team has developed a procedure to troubleshoot the problem 
and plans to perform it later in the mission.



In the Large Isothermal Furnace, Voss completed the second of five 
planned runs Saturday afternoon for the Diffusion of Liquid Metals 
study using the Large Isothermal Furnace. Diffusion is the process by 
which liquid metals mix without stirring -- similar to how the smell 
of baking bread, for instance, spreads from the oven throughout the 
house. The experiment is designed to reveal the diffusion coefficient 
-- a fundamental quantity which describes the diffusion process -- of 
liquid tin in relation to temperature.



During the fourth run, researchers noticed the helium consumption was 
greater than expected and ended the final rapid cooling step of the 
experiment early to conserve helium. Another run of the Liquid Phase 
Sintering experiment, which does not require helium, was activated in 
the facility, while researchers assess the helium consumption rate. 
The investigation under way examines the sintering process, or how 
particles bond when heated, in solid-liquid mixtures.



The EXPRESS Rack facility has been experiencing problems relaying 
housekeeping information, such as temperature, air pressure and water 
flow, to the ground. The crew is monitoring read-outs and voicing 
down information every two hours. Troubleshooting continues to 
determine the cause and corrective actions.



Today, Linteris is scheduled to conduct another test of the soot 
experiment, and another diffusion of liquid metals study will be 
activated in the Large Isothermal Furnace.



The next scheduled Public Affairs status report will be issued at 
approximately 6 a.m., July 7.

	
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