Microgravity Research Opportunities for the 1990s (1995) / Chapter Skim
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Microgravity Research Opportunities for the 1990s: Executive Summary
Microgravity Research Opportunities for the 1990s: Executive Summary
Pages 12-31
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From page 12... ...
It is especially noteworthy that these disciplines are laboratory sciences that inherently use controlled, model experiments. Many experiments require constant attention and frequent intervention by the experimenter, which distinguishes microgravity research from the observational space sciences.
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From page 13... ...
It should be understood at the outset that in evaluating the costs of doing research on such expensive vehicles as a space station, vehicle expenses are specifically not included. Microgravity research has never been the sole motivation for the space shuttle or other major space missions.
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From page 14... ...
The essential features of the recommendations are to emphasize microgravity research for its general scientific and technological value, as well as its role in advancing technology for the exploration of space; to deemphasize the research value of manufacturing in space with the intent of returning products to Earth; to modify NASA's infrastructure, policy, and procedures so as to facilitate laboratory science in space; to establish priorities for microgravity experimentation in scientific disciplines and subdisciplines in accordance with the relative opportunities for scientific and technological impact; and to recognize fluid mechanics and transport phenomena as a central theme throughout microgravity research. The recommendations detailed in this report are based on certain findings that resulted from this study.
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From page 15... ...
Research on materials processing in microgravity, however, could prove to be important for materials science and materials processing technology on Earth. Fluid mechanics and transport phenomena represent both a distinct discipline and a scientific theme that impacts nearly all microgravity research experiments.
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Decisions on the availability of platforms such as a shuttle or space station are essentially programmatic issues in which microgravity research is only one of many considerations. RECOMMENDATIONS FOR THE SCIENCE PROGRAM file:///C|/SSB_old_web/mgoppes.htm (5 of 21)
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From page 17... ...
Fluid Mechanics and Transport Phenomena Fluid mechanics and transport phenomena play a dual role in the microgravity research program. They stand as distinct disciplinary areas but also appear as themes running through other disciplines.
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From page 18... ...
. In a reduced-gravity environment, multiphase flows and associated transport phenomena become significantly different because of the altered orientation of the various phases.
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From page 19... ...
Clearly, fluids and transport phenomena appear as critical technical issues in many spaceflight-enabling technologies. Combustion Combustion involves fluid mechanics, mass and heat transport, and chemical reaction-all directly or indirectly subject to numerous gravitational effects.
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Laboratory scale-up at 1 g introduces unwanted buoyancy. Reduced gravity would allow a scale-up in overall size without the introduction of major buoyancy effects, thus permitting access to the smallest scales of turbulence that are important to the problem.
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2. Further experimentation is needed in both terrestrial and microgravity environments to develop new methods, materials, and techniques to exploit the potential of microgravity, where it exists, for improvements in biochemical separations.
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Growth of Inorganic Single Crystals. The microgravity environment will be particularly useful for the study of transport phenomena in the liquids from which bulk crystals are grown, and priority should be given to these studies rather than to the growth of large crystals.
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From page 23... ...
Any experiments on bulk crystal growth must be judged by their potential to contribute to the scientific understanding of the fundamental processes of crystal growth. The recommendations for this area of research are as follows: The design and execution of microgravity experiments that lead to a better fundamental understanding of crystal growth have proved elusive, and the committee recommends against the growth of large inorganic crystals under low gravity.
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From page 24... ...
3. Mass transport and diffusion studies of glass and ceramic melts under microgravity conditions should generate more precise data than those available from terrestrial measurements.
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This program can include such important studies as fundamental physics measurements (e.g., verification of the equivalence principle) , critical phenomena, dynamics of crystal growth, and low-density aggregate structures.
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From page 26... ...
The need for scientific judgment, trained observation, and human intervention and participation in certain laboratory microgravity experiments requires a greater use of payload specialists with expertise and laboratory skills directly related to the ongoing experiments. Some flight experiments would also benefit from the direct investigator interaction made possible by teleoperation capabilities, and NASA should support the development and deployment of such techniques in future microgravity experiments.
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From page 27... ...
NASA should categorize experiments according to their minimum facility requirements to maximize scientific return and cost-effectiveness. Drop towers, aircraft on parabolic trajectories, sounding rockets, and orbiting platforms supply a range of acceleration levels, acceleration spectra, and experimental durations and provide opportunities for human interaction and demonstration of reproducibility of results.
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From page 28... ...
The present microgravity research infrastructure does not readily accommodate the needs of laboratory research. Although drop towers and airplanes flying parabolic trajectories can be used for special or precursor experiments and some materials processing can be done on free-flyers, the spacelab and space station are better suited for microgravity laboratory research.
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From page 29... ...
Biotechnology is tied strongly to other microgravity programs because it shares fluids and transport phenomena as the common scientific theme through which gravity becomes an important parameter. The administrative issue concerns the need for cooperation and coordination between the microgravity research administration and the life sciences administration for research on cellular and subcellular processes and mechanisms.
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From page 30... ...
It is necessary to increase substantially the number of ground-based investigations to ensure the future supply of high-quality flight experiments. Consequently, the budget for ground-based research should be increased as a fraction of the entire microgravity program.
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From page 31... ...
This archive should contain a bibliography of all published scientific papers and reports on microgravity subjects and should preserve the original spaceflight data sets, such as photographs and electronically recorded data. An additional point of concern is that given the long time scale for the development through flight of a space experiment, there is a real danger that the scientific goals of the experiment might be bypassed by new developments or by major shifts in the value ascribed to the work.
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