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Toward a Microgravity Research Strategy (Chapter 2) Toward a Microgravity Research Strategy 2 Status of the Field Microgravity research is a diverse multidisciplinary effort that has been subdivided into so-called disciplines. Each has been associated with a discipline working group (DWG) operated previously under the auspices of the Universities Space Research Association. Typically, each DWG has consisted of 5 to 10 interested scientists and engineers. All of the groups have been chaired by a person from outside NASA and cochaired by someone from a NASA center. These groups are biological sciences; combustion science; electronic materials; fluids, interfaces, and transport; fundamental processes; glasses and ceramics; and metals and alloys. The CMGR has met with representatives of these DWGs, studied their reports, reviewed previous status and workshop accounts on the field of microgravity research, such as Materials Processing in Space,1 Microgravity Science and Applications: Report on a Workshop,2 and Review of Microgravity REPORT MENU Science and Applications Flight Programs—January-March /987,3 and conducted NOTICE independent investigations. This process has resulted in summaries of the status MEMBERSHIP of each disciplinary area except fundamental processes, which, as has been SUMMARY indicated, is summarized in Space Science in the Twenty-First Century: CHAPTER 1 Imperatives for the Decades 1995 to 2015—Fundamental Physics and CHAPTER 2 Chemistry;4 these summaries are presented in appendixes A to F of this report. CHAPTER 3 CHAPTER 4 APPENDIX A As regards the status of the field, the Committee on Microgravity APPENDIX B Research reached the following conclusions: APPENDIX C APPENDIX D The current subdivision of microgravity research into seven APPENDIX E "disciplines," as represented by the DWGs, is obsolete and misleading. Thus the APPENDIX F CMGR recommends that microgravity research be reorganized into the following six categories: Biological science and technology, Combustion, file:///C|/SSB_old_web/cmgr92ch2.htm (1 of 4) [6/18/2004 11:08:53 AM]

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Toward a Microgravity Research Strategy (Chapter 2) Fluid science, Fundamental phenomena, Materials, and Processing science and technology. These six areas, as opposed to the former seven "disciplines," are chosen to reflect future opportunities more realistically. For example, combustion would entail consideration of both combustion science and fire safety; fluid science would address not only classical fluid dynamics, but also the mechanics of drop dynamics and the physics of free fluid boundaries; and processing science and technology would emphasize phenomena instead of a particular material and sometimes would be conducted on model materials of little practical value. Materials would encompass situations in which the material itself (whether metal, ceramic, glass, polymer, or composite), rather than a processing phenomenon, is the primary object of study. Development is more advanced in the DWG areas of fluids, interfaces, and transport; metals and alloys; and combustion science than in the other historical DWG areas. Studies in the area of biological sciences show promise in protein crystal growth, but little in other directions such as electrophoresis. However, current research activities in protein crystal growth are largely exploratory and empirical and hold out little hope of explaining why protein crystals grow differently in space or how to exploit such differences. Excellent, but only a few, experiments are being done in the area of fundamental phenomena. Future experiments are likely to materialize from unsolicited proposals rather than from NASA's Announcements of Opportunity (AOs). Research in the area of electronic materials has concentrated thus far on bulk materials and so is out of the mainstream of current technology, in which research on electronic properties focuses on the properties of thin films deposited on substrates. In some cases, however, the quality of the bulk crystals used as substrates can influence the properties of epitaxial films, and, in limited applications, bulk crystals are used as primary components. Therefore, some research on them is likely to be of practical value and could produce information of scientific importance to materials processing. Glasses and ceramics constitute a relatively underdeveloped area at present; some research overlaps with that done in metals and alloys. file:///C|/SSB_old_web/cmgr92ch2.htm (2 of 4) [6/18/2004 11:08:53 AM]

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Toward a Microgravity Research Strategy (Chapter 2) Microgravity research is a relatively new and laboratory-intensive field that requires frequent access to space. To date, progress has been limited considerably by the paucity of flight opportunities. REFERENCES 1. Committee on Scientific and Technological Aspects of Materials Processing in Space, Space Applications Board. 1978. Materials Processing in Space. National Academy of Sciences, Washington, D.C. 2. Solid State Sciences Committee, Board on Physics and Astronomy. 1986. Microgravity Science and Applications: Report on a Workshop. National Academy Press, Washington, D.C. 3. Review Committee, J. Robert Schrieffer, chairman. 1987. Review of Microgravity Science and Applications Flight Programs—January-March 1987. Universities Space Research Association, Washington. D.C. 4. Task Group on Fundamental Physics and Chemistry, Space Science Board. 1988. Space Science in the Twenty-First Century: Imperatives for the Decades 1995 to 2015—Fundamental Physics and Chemistry. National Academy Press, Washington, D.C. file:///C|/SSB_old_web/cmgr92ch2.htm (3 of 4) [6/18/2004 11:08:53 AM]