STS-87 Mission Science Report # 13s
Tuesday, December 2, 1997, 7:00 a.m. CST
Microgravity Science Laboratory researchers at Marshall Space Flight Center in Huntsville, Ala., are working to take maximum advantage of the remaining hours before Space Shuttle Columbia’s return to Earth Tuesday. A malfunction in the Shuttle’s number two fuel cell will end the mission much earlier than the planned return on April 20.
Though disappointed because of the need to cut the mission short, Mission Manager Teresa Vanhooser at the Marshall Center said that the Spacelab science control team was working with the crew members aboard Columbia to reduce experiment run times and to realign the mission’s schedule to maximize the scientific return. Researchers hope to get as many science experiments completed as possible in the short time remaining.
Despite this condensed time period, researchers have been able to record a “first” in the Combustion Module.
“We’ve hit a homerun -- it’s the first truly steady non-buoyant flame that’s been observed by anybody anywhere on Earth,” said Combustion Scientist Dr. Gerard Faeth from the University of Michigan, Ann Arbor. While describing results from the Laminar Soot Processes experiment, he stated that scientists have gotten their first glimpse of the concentration and structure of soot from a fire burning in microgravity. “It’s a real first and the pictures we saw today will probably find their way into textbooks of the future,” said Faeth.
Much of the energy from fire is expelled in the soot it produces. Researchers are gaining a better understanding of the role soot plays in combustion and how it is produced by different fuels. “Soot has a lot of negative attributes and that’s why we’re concerned about it. It’s a pollutant,” said Faeth. “It is harmful to public health. It is the major source of difficulties of unwanted fires in homes. Soot has carbon monoxide associated with it, which is toxic and in that role soot is responsible for the deaths of about 4,000 people a year in the United States, and it’s responsible for fire injuries of about 25,000.”
Working in concert with science teams on the ground at the Marshall Center, Columbia crew members Dr. Gregory Linteris and Dr. Don Thomas continued experiments in TEMPUS, a German acronym for the electromagnetic levitation furnace facility. These investigations were pushed up in the timeline, according to William Hoffmeister, assistant TEMPUS investigator at Marshall Center. The team was able to activate, observe and complete an experiment run by melting a zirconium metal sample and levitating it in the facility. This experiment, led by Vanderbilt University Professor Robert Bayuzick, is studying the relationship between internal flows in liquids and the amount of undercooling that can be tolerated before solidification occurs. “To understand this experiment,” Bayuzick said, “imagine if you cooled a glass of distilled water. The temperature could go below freezing without the water actually becoming ice. That is undercooling. However, if the glass were tapped or disturbed, then the water would freeze very quickly. This process may have many benefits to industry. New, enhanced properties in never-before-seen materials could become possible.”
Thomas continued work in the middeck Glovebox as he conducted the experiment called Internal Flows in a Free Drop. Tracer particles inside the drop gave scientists the ability to map the internal flows taking place as the drop was manipulated by sound waves. Understanding the flows of fluids has far reaching applications for scientists in the areas of weather prediction and ocean flows. Acoustic positioning using this containerless technique is important to industries such as chemical manufacturing, petroleum, cosmetics and food sciences.
Later Thomas also set up the Large Isothermal Furnace for the Liquid Phase Sintering experiment. This investigation tests theories on how liquefied materials form a mixture without reaching the melting point of the new alloy combination.
Pilot Susan Still monitored the cooling samples from the earlier Large Isothermal Furnace experiments. These dealt with the diffusion of different types of metals. Diffusion is a process where two compounds mix -- much like how a droplet of food coloring will slowly mix into a glass of water. After Columbia’s return, researchers will cut the column of lead-tin-telluride into segments to study how uniform the various components mixed during sample cooling.
Before the end of his shift, Linteris continued work in the combustion module, performing the Droplet Combustion Experiment. The purpose of this experiment is to collect information on the burning rates of flames, flame structures and conditions when extinguishing a flame. With improved understanding of droplet combustion, the results of this experiment could lead to cleaner and safer ways to burn fossil fuels, and more efficient methods of generating heat and power on Earth.
The experiment, Coarsening in Solid-Liquid Mixtures investigation was moved up in the schedule as well. This experiment may help researchers develop improved manufacturing processes and stronger alloys. Because the coarsening experiment was moved up, it was decided that the Astro/Plant Generic Bioprocessing Apparatus would remain stowed in the middeck compartment.
Meanwhile, protein crystal growth experiments continue unattended as planned.
During this shift, researchers also dealt with a temporary malfunction of the Experiment Control Systems Computer. This computer oversees all the experiments aboard Spacelab. Commander Jim Halsell Jr. ran trouble shooting steps to remedy the problem. Science experiments continued after only a short interruption.
The next scheduled Public Affairs Status report will be issued at approximately 6 a.m., April 7.
For more information call Spacelab Newscenter at Marshall Space Flight Center at (205) 544-6535 or visit our web sites. For Spacelab payload information: http://liftoff.msfc.nasa.gov/spacelab/msl/main.html and for microgravity science information: http://www.ssl.msfc.nasa.gov/msl1/ msl1hframe.htm
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