outfitting, and maintenance of the International Space Station (ISS) itself. Consequently, when considering whether to add non-ISS flight opportunities, NASA must weigh the benefits of providing continuing flight research opportunities to nurture, develop, and sustain a research community that will be ready to use the ISS against the benefits of completing the assembly of the ISS on schedule and within budget.
The space station has been officially under development by NASA since the late 1980s. During that time, the scope of the effort has been reevaluated, resized, and redistributed several times, with perhaps the largest rescoping of the design occurring in 1992–1993. At that time NASA distributed some of its costs and development responsibilities among several international partners in exchange for research time and resources aboard the ISS. As a result of changes in both the design of the ISS and its schedule for development, it has been necessary for NASA to reexamine repeatedly the station’s ability to support its promised goal of “world-class research” in both the biological and physical sciences. NASA noted as follows in “International Space Station Familiarization: Mission Operations Directorate Space-Flight Training Division,” July 31, 1998, available on its Web site:
The purpose of the ISS is to provide an earth orbiting facility that houses experiment payloads, distributes resource utilities, and supports permanent human habitation for conducting research and science experiments in a microgravity environment (ISSA IDR no. 1, Reference Guide, March 29, 1995). This overall purpose leads directly into the following specific objectives of the ISS program:
Develop a world-class orbiting laboratory for conducting high-value scientific research.
Provide access to microgravity resources as early as possible in the assembly sequence.
Develop effective international cooperation.
Provide a testbed for developing 21st Century technology.
The changes in schedule and cost projections throughout the 1990s have prompted reevaluations of the number and scale of the major facilities that would eventually be placed on board; the schedule for developing, deploying, and utilizing those facilities; and the critical resources such as crew time and electrical power needed to support ISS science research.
Specific concerns over schedule delays and potential downgrading of ISS research capabilities have been growing for several years in the scientific community (Sigler et al., 2000) and have been cited in a number of NRC reports reviewing space laboratory sciences (NRC, 1992, 1997, 1998). More recently, internal scientific committees that advise NASA at various organizational levels have voiced considerable alarm at the possibility of further reductions in ISS science support capabilities (Sekerka, 2001; Fettman, 2001; Katovich, 2001). In the fall of 2000, Congress directed that the National Research Council and the National Academy of Public Administration (NAPA) should organize a joint study of the status of microgravity research in the life and physical sciences as it relates to the ISS. As detailed in the preface, the study is being conducted in two phases. For this phase-1 report, the NRC was asked to address the questions of the state of readiness of the scientific community to use the ISS for life and physical sciences, and to work with NAPA on an assessment of the relative costs and benefits of dedicating a yearly space shuttle mission for research versus simply maintaining the current schedule for assembly of the ISS.