STS-94 Mission Science Report # 2s
Wednesday, July 2, 1997, 6 a.m. CDT
Overnight, Columbia’s crew continued to transform the Spacelab into an operational, sophisticated multi-use research laboratory by activating Microgravity Science Laboratory Mission - 1’s experiment facilities . The space-borne laboratory, with a work area approximately 18 feet by 7 feet, houses most of the 25 primary experiments, four glovebox investigations and four accelerometer studies aboard Columbia.
On the ground, mission scientists are using lessons learned from STS-83 to get the most out of the reflight opportunity. “Experience gained from our first flight has allowed us to make changes in our plans and procedures in order to perform this scientific research more effectively,” said Dr. Patton Downey, assistant mission scientist.
In the Spacelab, the blue shift science crew members -- Payload Commander Dr. Janice Voss and Payload Specialist Dr. Roger Crouch -- spent much of their shift readying experiment facilities and activating protein crystal growth and accelerometer experiments.
In the middeck, Crouch activated the Protein Crystallization Apparatus for Microgravity -- one of three protein crystal growth experiments slated for MSL-1. The microgravity environment of space allows researchers to grow larger and more perfect specimens. Once back on Earth, scientists perform X-ray diffraction studies on the specimens to determine their structures. Better understanding of a protein’s structure could allow scientists to design more effective drugs to treat diseases such as cancer, diabetes, alcoholism, AIDS and Alzheimer’s. The Protein Crystallization Apparatus for Microgravity experiment is led by Dr. Daniel Carter of New Century Pharmaceuticals in Huntsville, Ala.
The four microgravity measurement systems have been activated to begin monitoring any slight disturbances in the weightlessness environment aboard Columbia. The Orbital Acceleration Research Experiment, which began its operations at launch, will measure very low frequency accelerations in the Shuttle’s payload bay. On orbit, Microgravity Measurement Assembly sensor heads -- which will be used to monitor the microgravity environment inside Spacelab -- have been installed into areas of the Spacelab where gravity-sensitive investigations are located.
Voss installed and activated the Space Acceleration Measurement System sensors which will be used to monitor accelerations near the Large Isothermal Furnace and the Glovebox. She also installed the Quasi-Steady Acceleration Measurement System’s optical disk that will be used to record very low frequency and residual accelerations in one of Spacelab’s racks. NASA’s Lewis Research Center in Cleveland, Ohio manages all of the acceleration measurement experiments.
Voss completed her first shift by mounting and activating the Protein Crystal Growth experiment using Hand-Held Diffusion Test Cells in the Spacelab. She also set up video equipment to monitor the experiment. The experiment’s principal investigator, Dr. Alex McPherson of the University of California in Riverside, Calif., hopes to use data from this experiment to refine cell design and optimize growth procedures and conditions for future Protein Crystal Growth experiments.
Dr. Roger Crouch prepared the electromagnetic containerless processing facility or TEMPUS, for operations. Developed by the German Space Agency, TEMPUS allows scientists on the ground to process metallic samples in a containerless microgravity environment. A metal alloy sample -- about a third of an inch in diameter -- will be suspended in a free space within a set of coils, melted and then resolidified. Video cameras and heat sensors will analyze how the specimens change shape -- yielding basic information about the materials' properties that are masked by gravity on Earth. Information gained from the samples to be processed in the TEMPUS facility could lead to improved welding, casting and soldering techniques on Earth.
After crew handover near midnight, the red shift consisting of Mission Specialists Dr. Michael Gernhardt and Dr. Donald Thomas and Payload Specialist Dr. Gregory Linteris continued to activate experiment facilities aboard Spacelab.
First, Thomas activated the Large Isothermal Furnace. The vacuum-heating furnace is designed to heat large samples uniformly. It has a maximum temperature of 2,912 F and can cool a sample rapidly through the use of a helium purge. The research team will command the heating and cooling processes from the ground so they can make real-time changes to enhance science operations.
Scientists are using this facility to study a familiar process -- diffusion. This is the process that for instance, helps carry the smell of baked bread from the oven throughout the house, or allows food coloring to disperse through a glass of water without stirring. This process is also very important in the study of metals and alloys, and on the ground. However, the diffusion process can be masked by fluid motions arising from the effects of gravity. Knowledge gained from unmasking the process in the microgravity environment could improve materials processing on Earth.
In the early morning hours, Linteris activated MSL’s third and final protein crystal growth experiment -- the Second Generation Vapor Diffusion Apparatus. The experiment is led by Dr. Larry Delucas of the Center for Macromolecular Crystallography at the University of Alabama in Birmingham.
Later, Thomas readied the EXPRESS Rack for science operations by connecting the power cable, configuring the water loop, opening the water control valve and turning on the facility. He then activated the Physics of Hard Spheres experiment that will take place in the EXPRESS Rack. Headed up by Dr. Paul Chaikin of Princeton University in New Jersey; the experiment will examine the changes which occur during the transition of a substance from liquid to solid and solid to liquid. Results of the experiment could improve the design of metallic alloys and processing techniques.
Ahead, Linteris will begin a study of the properties of soot in the Combustion Module-1, and Thomas will begin a study in the Large Isothermal Furnace to measure the fundamental variables which regulate the diffusion of impurities in molten salts.
The next scheduled Public Affairs status report will be issued at approximately 6 p.m., July 2.
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