As part of its mandate to guide the nation’s civil space program, NASA is to preserve U.S. preeminence in critical aspects of space science, technology, and applications. The goal of life and microgravity sciences is to study gravity-dependent physical phenomena and those phenomena obscured by the effects of gravity in biological, chemical, and physical systems. Research is conducted in biotechnology (e.g., protein crystal growth), combustion science, fluid physics, life and biomedical sciences, and materials science. Life science research in space biology studies the effects of gravity on living systems by using acceleration environments across the “gravity continuum”—micro, earth-normal, and hypergravity. NASA’s Office of Life and Microgravity Sciences and Applications, which was formed in 1993, funds this type of research. Between fiscal years 1989 and 1994, the annual budget authority for life and microgravity research increased by 114 percent, from $222.4 million to $476.3 million. Not all aspects of life and microgravity sciences research require a space-based environment. Short duration, low acceleration environments can be created in drop towers (2 to 5 seconds of free fall), aircraft flying a distinctively curved flight path (up to 23 seconds of low gravity), and suborbital rockets (over 300 seconds). Hypergravity can be created by a centrifuge. Space-based research is principally conducted in pressurized and nonpressurized facilities on the Space Shuttle. The centerpiece for this research is a 23-foot by 16-foot pressurized module—Spacelab—that fits in the Space Shuttle payload bay. Spacelab was developed by the European Space Agency and contains utilities, computers, work areas, and instrument racks for experiments. An exterior cutaway view of Spacelab is shown in figure 1. The most recent Spacelab flight was the second International Microgravity Laboratory (IML-2), which ended a 15-day mission on the Space Shuttle on July 23, 1994. IML-2 was a collaborative effort by NASA; the European Space Agency; and the national space agencies of Canada, France, Germany, and Japan. According to NASA officials, IML-2 provided a preview of the science operations to come on the space station. The IML flights, which began in January 1992, gave the U.S scientific community access to foreign-developed flight hardware while providing the international research community with access to the Space Shuttle/Spacelab. Approximately 80 investigations were performed on IML-2, including 15 U.S. experiments—11 in the biotechnology, fluid physics, and materials science and 4 in the life sciences. IML-2 was the last flight of this international series of spacelabs before the station era begins in 1997. An interior view of IML-2 is shown in figure 2. NASA publicly solicits research proposals from investigators in the life and microgravity research communities. The funding decision is principally based on an evaluation of the project’s scientific merit by a peer review panel. NASA’s peer review and other quality assurance procedures are outlined in appendix I. NASA intends to build a space station-era research community from the ground up. To do so, a larger cadre of ground-based researchers than currently available will be needed to adequately support U.S. research on the station. A NASA official estimates that the number of ground-based microgravity researchers needs to increase from 73 to 240 between fiscal years 1992 and 1998. NASA officials have not made comparable estimates for life science researchers. To accomplish this goal, NASA has abandoned its tradition—principally associated with life science research—of soliciting research proposals for general and specific space flight opportunities. Although this approach appears reasonable, the planned funding levels do not match the program’s objective, and funding priorities may need to be reassessed if the number of life and microgravity ground-based investigators is to be significantly increased. In recent years, NASA has used two approaches for developing life and microgravity science research communities—“select for flight” or “select for science.” In the select-for-flight approach, all of the U.S. life science and most of the U.S. microgravity investigators on IML-2 were selected from proposals submitted in response to flight-related announcements. In the select-for-science approach, two IML-2 microgravity investigators were selected from researchers who submitted proposals in response to two 1991 discipline-related (“fundamental science” and “biotechnology”) research announcements. A NASA program scientist considers the IML-2 flight to have been a programmatic success and, in some respects, a model for the international space station. According to a NASA official, one indication of the flight’s success was the amount of good research generated from the many proposals submitted in response to a mix of science and flight-related research announcements. Additionally, two of NASA’s recent research announcements were in the select-for-flight tradition: its July 1993 announcement soliciting proposals for research on a 1998 space life sciences flight (Neurolab) and its February 1994 announcement soliciting proposals for life science research on the Russian space station Mir from 1995 to 1997. Presumably then, one effective way to develop a research community would be to solicit specific proposals for research that are directly related to the space station. NASA, however, has chosen to move toward exclusive use of “select for science,” as discussed below. Although NASA recently solicited proposals specifically for research on Shuttle flights to Mir, NASA’s life science office changed from the widespread use of the select-for-flight approach in December 1993. At that time, it solicited proposals for ground-based research in space biology focused on the hypergravity effects that can be induced by NASA’s centrifuges. NASA’s shift to ground-based research did not stifle competition for funding: it received 650 responses to the December 1993 announcement. Although “select for science” is relatively new to life science research, all microgravity research announcements since 1990 have focused on research opportunities in one or more science disciplines. And, as if to emphasize the independence of microgravity research from space station development, NASA changed the fiscal year 1992 goals for the microgravity program. The previous goals referred to developing and using the space station, whereas the current, more general goal is to “enable research . . . by choosing the carrier most appropriate for the experiment.” Physical events, unlike biological processes, can be meaningfully observed under the short-duration microgravity conditions afforded by ground-based facilities, aircraft, and suborbital rockets. Consequently, a ground-based microgravity research investigator does not always have to conduct experiments in a space environment, and many do not. For example, of the 51 principal investigators who conducted such research at NASA’s Lewis Research Center from fiscal years 1989 through 1993, only 7 have been principal investigators on space-based experiments, including a microgravity Spacelab flight in September 1995. “NASA establish a vigorous ground based research program focussing on gravitational biology in which centrifuge facilities at NASA centers are utilized for exploring science programs aimed at forces greater than 1g .” NASA’s strategy for using the select-for-science approach to further develop a life science research community in the station-era appears reasonable based on the experience of the microgravity sciences community. First, the microgravity sciences research community has been growing. Principal investigators funded for microgravity sciences research increased by 120 percent—from 89 in calendar year 1989 to 196 in fiscal year 1993. The budget authority for microgravity sciences increased by 130 percent, from $75.6 million to $173.9 million during this period. The number of proposals submitted in response to research announcements also generally increased during this period. For example, although proposals submitted in response to materials, fluids, and fundamental (benchmark) physics research announcements decreased from 397 in 1991 to 217 in 1993, those responding to combustion physics announcements increased from 65 in 1989 to 98 in biotechnology research announcements increased from 94 in 1991 to 141 materials and fluids research announcements increased from 69 in 1990 to 346 in 1991. Second, the microgravity research community is stable but not stagnant. Fifty-five percent of all microgravity sciences investigators that were funded in 1989 were also funded in fiscal year 1993. This core group represents 25 percent of the investigators funded in fiscal year 1993. On the other hand, 44 percent of the investigators funded in 1993 were not funded in 1992. Third, NASA is attracting new investigators to its microgravity sciences program. The decline in proposals (from 397 to 217) submitted in response to the 1993 materials, fluids, and fundamental physics announcement may have been partly caused by NASA’s stated purpose of encouraging new investigators, and most of the 55 investigators funded from this announcement were new to the program. Only 15 of them had been previously funded by NASA. In June 1994, NASA’s life sciences advisory subcommittee recommended that NASA use this approach and establish appropriate categories within life science research announcements that recognize and encourage new investigators. Finally, for those proposals we reviewed, the select-for-science approach produced relatively fewer low peer review scores than the select-for-flight approach. Figure 3 shows that 8 percent of the select-for-science proposals received peer review scores in the bottom category, while 32 percent of the select-for-flight proposals received scores in the bottom category. Similarly, as figure 4 shows, of all the proposals in the bottom category, only 16 percent were in the select-for-science tradition, while 84 percent were in the select-for-flight tradition. Many of the proposals submitted in response to NASA’s research announcements were not considered scientifically meritorious. For example, peer review panels gave 129, or 44 percent, of the 290 proposals we reviewed relatively low scientific merit scores. NASA’s plans to expand its ground-based research program are not realistic based on planned funding.