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Ill Demand for Microgravity Research and Applications Activity In the United States, NASA has been the major sponsor of microgravity research and applications activities. The following sections discuss NASA's role in such research and outline existing and planned actions of other governmental and private organizations. NASA PROGRAMS Several offices of NASA have programs addressing research in the microgravity environment. The Office of Space Science and Applications (OSSA) programs encompass basic research on transport phenomena, materials, and industrial processes as well as research in the life sciences. The Office of Commercial Programs (OCP) attempts to bring together academic research and industrial interest in commercially relevant advances in materials and processes that might be made in the space environment. To do this it has created a number of Centers for the Commercial Development of Space focused on relevant disciplines. In a broader context than just microgravity research, the Office of Aeronautics and Space Technology (OAST) performs basic research on structures and other technology development and, in the context of in-space research, tests the efficacy of new technological developments in situ. The Office of Space Station also plans to utilize in-space proof-of-concept technology demonstrations and demonstrations of research equipment in advance of the Space Station's deployment. Space Science and Applications Activities The OSSA microgravity activities address research in the areas of materials (including metals and alloys, electronic and photonic 15
materials, ceramics and glass), fluids and transport phenomena, combustion, fundamental physics and chemistry, and biotechnology and life sciences. The main program focus has been toward materials science, not only because the scientific questions surrounding this field are profound, but because of its potential for practical applications. Consideration is also being given to broadening the scope of research on transport phenomena in order to expand its applications to diverse industrial processes. The flight research program is centered about three different capabilities provided by the Space Shuttle system, viz., the Spacelab, the orbiter middeck, and the cargo bay; ultimately, the capabilities of the Space Station will be used. Current OSSA planning reflects the reality of flight availability. In terms of demand, microgravity flight opportunities are formally manifested on the Shuttle through FY 1994. Primary payloads (e.g., Spacelabs) have been essentially fully booked for the manifested microgravity missions by OSSA as far out as the USML-1 Spacelab flight (scheduled for the STS-54 flight in early 1992). The OSSA allocation of the USML-1 experiment space (50 percent of the total, with the remainder allocated to OCP) has not yet been filled, but OSSA believes that it will be. Microgravity experiments are not yet specifically manifested for flights after USML-1. The current OSSA demand for microgravity research is outlined in Appendixes C and D. As can be seen from those appendixes, the planned/proposed experiments fall into two broad categories: those related to materials science and transport phenomena and those related to the life sciences. Experiments in Materials Science and Transport Phenomena Studies of materials science and transport phenomena in space are closely coupled. Each represents a typical laboratory science that requires human interaction with the experiments to make observations and identify novel or unexpected effects. There have been limited flight opportunities to gain a better understanding of the complex phenomena involved in microgravity processes or to develop experimental facilities. Most of the microgravity experiments performed to date have carried into space materials processing techniques that were developed and optimized for a terrestrial environment in order to identify phenomena and improvements that might result from the suppression of gravitational effects. Such a trend is likely to hold for the period prior to Space Station operations. The committee believes that only when scientists can live and work in space for extended periods, with sufficient resources and capabilities to investigate new ideas, will new processing techniques be developed that take full advantage of the unique microgravity environment, that is, techniques that by their inherent nature cannot be developed on Earth. 16
The committee reviewed the OSSA Microgravity Science and Applications Divisions (MSAD) program, which has responsibility for the activity in materials science and transport phenomena. The committee believes that MSAD has developed a strategic plan for the development of microgravity research in materials science and transport phenomena along an evolutionary path that allows necessary manned intervention and provides for the creation of facilities and enabling technologies leading to the productive use of the Space Station, when it becomes available. That plan has not indicated a requirement for CDSF-like facilities. The 1989 budget for MSAD was $75.6 million, up from $62.7 million in 1988, and a 23 percent increase (to $92.7 million) is requested for 1990. Experiments in the Life Sciences The main thrusts of OSSA life sciences research are directed toward (1) understanding human physical reactions and adaptation to both short- and long-duration flights and the development of ways to offset any deleterious effects that occur in flight as well as after return to earth, and (2) the conduct of basic research to improve understanding of life processes and the origins of life. The life sciences flight program strategy for the 1990s is built around the existing and planned capabilities of the Shuttle, Spacelab, and Space Station. The life sciences microgravity program includes research efforts in the areas of cellular and molecular biology, botany, genetics, and organismic biology. Exposure to microgravity induces changes in fluid-electrolyte balance; endocrine function; neurophysiological function; immune system, cardiovascular, and renal function; bone mineralization; and muscle mass. It is uncertain whether microgravity alone is responsible for these alterations, since a combination of factors that cannot be simulated in their totality on Earth may be involved. However, it is essential to understand the impact of microgravity on life and life-support systems before undertaking extended human space flights. Much of the NASA OSSA life sciences microgravity research program focuses on identifying important mechanisms associated with microgravity-induced changes in biological functions and on developing the countermeasures needed to restore a "normal" equilibrium. The investigative work concerns the effects of microgravity on (1) bone mineral metabolism, (2) structural and material properties of soft and mineralized tissues, (3) immune function and cell differentiation, (4) embryogenesis, (5) membrane transport, (6) muscle contractile properties, (7) protein synthesis and degradation in various tissues, (8) gene expression, (9) signal transduction, (10) extracellular matrix organization, (11) tissue energetics, (12) motor unit function, (13) neural activation, (14) root growth, (15) tissue regeneration, and (16) endocrine functions. 17
Because of the lack of a long-duration, space-based research capability, life science research has focused on short-term, Shuttle-based studies that require human-tended operations. However, researchers acknowledge the need to investigate longer exposures to microgravity for various subfields in the life sciences. Besides those experiments requiring human subjects, most other investigations depend on human intervention for their execution. At present, NASA is proceeding with studies and development to provide a capability to conduct life science investigations on unmanned, free-flying, recoverable bioplatforms. The ability to perform studies of longer term phenomena and space radiation effects is the prime driver for the activity rather than the need for high-quality microgravity. Life sciences' flight requirements appear in Appendix D. The 1989 budget for life sciences research was $78 million, of which $36 million is for microgravity flight programs. An increase in the life sciences budget to $124.2 million is requested for 1990, of which $70.4 million would be for microgravity flight programs. Commercialization Activities In 1984 Congress declared "that the general welfare of the United States requires that the National Aeronautics and Space Administration seek and encourage, to the maximum extent possible, the fullest commercial use of space." As a response to this directive and Presidential pronouncements of that same year, NASA established the Office of Commercial Programs (OCP). The OCP sponsors flight experiments and hardware systems primarily through Joint Endeavor Agreements (JEAs), Space System Development Agreements (SSDAs), and the activities of the Centers for the Commercial Development of Space (CCDSs). A large number of experiments have been proposed, particularly by the CCDSs. They are rated primarily on the basis of commercial potential and appear not to have been reviewed yet for technical merit. Enhanced interaction and cooperation between OCP and OSSA could lead to greater scientific understanding in the OCP programs and to other advantages associated with "feedback" between the two offices. In essence, the commercialization process starts with an idea for a potential research or commercial activity, proceeds through ground-based and flight research phases, development, and finally to pilot projects, initial production, test marketing, and full-scale production. The OCP has estimated that a period of about seven years from inception of a concept will normally be required to reach the pilot production phase for any promising microgravity process. Thus, until at least the mid-1990s, NASA's commercialization program for microgravity essentially will be in a research and development stage. The current flight strategy, therefore, is similar to that evolved by MSAD, except that it relies primarily on secondary payload manifesting. 18
OCP has facilitated research in materials and processes and in biomedical and agricultural areas. Much of the potential commercial interest in the life sciences, as documented by OCP, requires access to microgravity for a short duration (<16 days). OCP microgravity experiments are expected to continue to be carried mainly as secondary payloads. Appendix E contains OCP's estimates of experiments that will need to be flown through FY 1996. It is the committee's view that, at present, the commercially oriented microgravity payload manifests of OCP appear to be less firm than those of OSSA. At the same time, OCP planning incorporates the ability to respond quickly to the unanticipated availability of secondary payload space. The 1989 OCP budget for the commercial use of space was $28.2 million, and $38.3 million has been requested for 1990. Advanced Space Technology Development Most existing space technologies have been developed on the ground and then tested in a flight program. However, future space systems are likely to be large and expensive. Thus, undertaking feasibility, or proof-of-concept, demonstrations in space would seem to offer a cost-effective way to ensure technology readiness for future missions. Of necessity, in-space flight testing is becoming part of advanced technology programs. The Office of Aeronautics and Space Technology (OAST) has identified the following as the most likely technology areas to require such testing: ⢠space structures (assembly, dynamics, and control); ⢠fluid management; ⢠space environment effects; ⢠life support; ⢠information systems; ⢠space environment characterization; ⢠automation and robotics; and ⢠in-space operations. The current OAST strategy is based on the nature of the experiments, the available flight opportunities, and the planned budget. Present OAST plans call for the majority of the experiments to use the Shuttle bay, the Space Station's attachment points, or expendable launch vehicle (ELV)-based, free-flying spacecraft. Only a relatively small percentage are planned for the Shuttle middeck or the Space Station's U.S. Laboratory Module. Most, but not all, of the experiments are of durations that can be achieved on Shuttle-based facilities, and many require human interventions. Finding budgetary resources to define and develop such experiments poses a separate problem. Only one of the projects that could be accomplished in an untended mode is currently funded, and that only for the concept definition phase. 19
Space Station Development The Office of Space Station (OSS) has not identified any requirements for space-based microgravity research or technology development beyond those activities already planned for and manifested on the Shuttle. OSS believes that neutral buoyancy simulators, other simulators and prototype equipment, and Shuttle experiments have to date proven adequate to develop the necessary levels of confidence in technology and procedures. Terrestrial testing clearly is less expensive. The committee believes some pre-Space Station R&D will need to be performed in space, such as some long-duration materials research, but, in its deliberations the committee could find no Space Station-related technology or process development that could only be undertaken successfully on a human-tended free-flyer. Observations on NASA Microeravity Programs As the study committee examined the NASA microgravity programs described on the preceding pages, it noted some significant manifestations of the embryonic state of microgravity research, which follow. 1. Because of the immaturity of our understanding of basic processes in space, there is only a limited supply of the kind of reliable, powerful, flight-tested, general purpose or easily adaptable equipment needed for effective research programs. Because of this, it is not unusual for individual researchers to devote a decade to designing the hardware necessary to permit scientific investigation. Both time and sufficient resources will be needed to address this inadequacy. 2. The selection of flight experiments sometimes appears to be occurring on an ad hoc basis. OSSA has candidate flight experiments reviewed for scientific merit (see the report of the Schrieffer committee regarding this procedure ). The mission of OCP, however, is to encourage private participation, especially outside of the scientific research community, with the hope of eventually enabling successful commercial ventures. OCP programs thus are not as a matter of course reviewed for scientific and technical merit or even for redundancy with other research. The committee is concerned that the experiments selected for a national microgravity research program, a program conducted in a unique and expensive environment, should be carefully coordinated within NASA. NASA has conscientiously stood up to its mandate to promote the commercialization of space; the OCP Centers for the Commercial Development of Space must therefore pursue all reasonable paths in this direction. Nonetheless, the committee believes enhanced cooperation between OSSA and OCP could benefit both programs, could help ensure a greater return for the national investment, and could help 20
avoid nonproductive, redundant, or poorly conceived experiments that might reflect badly on the whole microgravity program. OTHER GOVERNMENTAL AND PRIVATE REQUIREMENTS FOR MICROGRAVITY RESEARCH Representatives from the National Institute of Standards and Technology (NIST) of the U.S. Department of Commerce met with the committee and expressed an interest in microgravity research, but their requirements are small. The committee also contacted relevant organizations within the Department of Defense--U.S. Air Force, Office of Naval Research, and Defense Advanced Research Projects Agency (DARPA)--only one of which identified in its planning a small anticipated demand for microgravity experiments. Thus the microgravity research and applications plans of governmental agencies other than NASA do not appear to be significant at this time. In addition to governmental and university involvement (by means of governmental funding) in research on materials and processes in a microgravity environment, not-for-profit and for-profit private entities have also expressed limited interest in such possibilities. In general, the not-for-profit entities have pursued their research in much the same manner as university groups, with support coming primarily from NASA program offices. The for-profit industrial interest has always been small, as measured by the amount of private resources invested in the program. A highly visible industrial investment in materials (pharmaceuticals) separation utilizing electrophoresis was essentially abandoned during a period of no flight opportunities when newly invented ground-based techniques made the space-based process too expensive for the particular product involved. At present, only one U.S. company has been identified as having an enduring commitment to research in a microgravity environment that is directed toward possible commercial products. Most industrial involvement is centered on collaborative/consultative projects with university-based NASA/OCP CCDSs. Those companies that have invested either at a nominal "in-kind" level (i.e., provision of staff, equipment, and facilities rather than funds) or that have made funds available clearly view their participation in terms of a long-term commitment directed toward developing a basic understanding of materials and processes. The relatively low level of industrial commitment to activity in the microgravity environment, especially in terms of work directed toward materials processing, is consistent with the conclusions of a number of NRC reports on the subject and even with observations of potential facility providers that "there are no manufacturing requirements." This low level of industrial commitment to microgravity research and development accurately reflects the perceived value of space experimentation compared with ground-based work directed toward similar industrial objectives. 21
MANUFACTURING IN SPACE The potential benefits of the microgravity environment for manufacturing are both direct and indirect. Direct benefits may be derived by producing materials or products in space and bringing them back to Earth for consumption. The value added in space processing, however, must outweigh the cost of transportation and of the use of space-based facilities. At the present time, the transportation costs alone are in the range of $5,000 to $10,000 per pound. It has been argued that certain pharmaceuticals, electronic materials (e.g., the semiconductor gallium arsenide), and some catalysts can be produced in space with sufficiently superior quality or in sufficiently greater quantity to render their production economically feasible. Very few people argue that this will happen in the near future, however. Indirect benefits are derived by studying a process for manufacturing a certain product in space under reduced gravity conditions where it is possible to control and study various parameters such as temperature, processing rates, and chemical composition gradients. Such separation of process parameters typically is unattainable on Earth. The findings from the space-based activity are then applied advantageously to alter and optimize manufacturing processes on Earth, for example, the production of chemicals, metals, and food items. Realization of these benefits does not require full-scale manufacturing in space. Setting up a manufacturing process or the study of such a process is a complex undertaking on Earth and even more difficult in space. The behavior of materials systems involving fluids (liquids and/or gases) can be profoundly different in space than on Earth and there is not yet a good data base describing this behavior. Fundamental experiments in space to provide this data are a necessary prerequisite to space manufacturing. In addition, step-by-step evaluation of a space-based manufacturing process must precede pilot plant investigation or production. On Earth the introduction of a new product from its concept to production typically requires several years. Such an undertaking in space would most likely take longer, at least until researchers move up the learning curve with experience. Since a data base for manufacturing materials in space is nonexistent and the number of (relatively primitive) experiments to date has been small, the committee believes that there will be no need for a facility to produce or manufacture materials in space within the next seven to ten years. This statement is not intended to detract from the potential long-term benefits of space manufacturing. Rather, it is intended to accent the immediate need for basic and applied research and development of materials processing under reduced gravity--an indispensable preamble to this aspect of the commercial exploitation of the space environment. 22
SUMMARY REQUIREMENTS FOR RESEARCH IN THE MICROGRAVITY ENVIRONMENT The committee explored needs for microgravity research with the following: the scientific and technical microgravity research communities associated with the NASA Office of Space Science and Applications; the NASA Office of Commercial Programs and the industrial and academic communities that are working with the Centers for the Commercial Development of Space; the defense research community; the Department of Commerce and the National Institute of Standards and Technology; and leading experts from government and corporations involved in research on materials and processes in the space environment. In addition, the committee investigated the needs for technology development and verification to facilitate transition into the Space Station era. The majority of the demand for microgravity research in the United States comes from NASA through the programs of either OSSA or OCP. The demand for microgravity research by federal agencies other than NASA was found to be minimal. Based on some hard data and many best estimates, the following specific requirements were identified by the committee. ⢠Duration: An examination of the anticipated needs of 83 proposers of microgravity experiments to NASA's OSSA Microgravity Science and Applications Division (MSAD) revealed that only 13 percent of experiments require periods in space longer than 16 days (the time expected to be available with the use of an extended duration orbiter, although a 28-day extended duration on orbit is also being investigated). This low demand for long-duration flight also holds true for OCP activities. (See Appendixes C, D, and E for the projected requirements.) The proposed experiments for which long-duration exposure is sought fall into the following categories: (1) Biotechnology research with living cells, including work with enzymes and protein nucleation. This type of long-duration (beyond a week) scientific investigation has yet to be conducted, and it is not clear what results can be anticipated. (2) Production of materials such as pharmaceuticals. (3) Crystal growth, for example, semiconductors and protein crystals. While this process can be performed on flights of a week or 16 days, a few researchers are seeking 90-180 day process durations for production of larger crystals. ⢠Power levels: An examination of the projected requirements of OSSA and OCP classes of experiments listed in Appendixes C, D, and E revealed that less than four percent need peak power levels greater than 2.0 kW, which will be available through the Shuttle with USMP, Spacelab, and so on during the 1992-1997 time frame. Obviously, however, higher power levels enable more experiments to be conducted simultaneously. 23
⢠Microgravity acceleration levels: Because of the paucity of microgravity experiments that have been flown with adequate measurements of the acceleration of gravity, there is little experimental data to use in specifying the requirements for future experiments. Instead, the results of limited experiments, simple analytical models, and (in the case of the most demanding and highest priority microgravity experiments) a computational fluid dynamics model, have been used to come up with plausible estimates of acceleration that are acceptable for different classes of experiments. The estimates will need to be verified by the results of many well-instrumented flight experiments. The nature of the acceleration requirements and their basis are set forth very well by Naumann. Appendixes C, D, and E include estimates of acceleration levels for the various NASA microgravity experiments. A large number of experiments specify maximum accelerations in the range of from 10" to 10" g. However, a number of important experiments may require less than 10" g. An example of the latter is obtaining a homogeneous distribution (< 1 percent variation) of a dopant or alloying agent within the final solid produced in bulk (diameter of about 1 cm) crystal growth experiments. NOTES 1. Public Law 98-361, 1984. 2. Schrieffer, 1987. 3. Joseph Allen, Space Industries, Inc., Presentation to Committee, December 15, 1988. 4. Naumann, June 8, 1988. 24
