Evolution Options Growth requirements are driven by two principal options or paths identified for space station evolution. One option addresses the growth of Space Station Freedom along a path consistent with its initial role as a research and development (R&D) facility in space. Subsequent to Phase I assembly completion, additional power, crew, pressurized volume and structure need to be added to the baseline space station along with new capabilities (e.g., satellite servicing) to accommodate growth in user demands. For the R&D evolutionary path, emphasis is placed on the science, technology and commercial payloads which reside within the pressurized lab modules or are attached to the truss structure outside of the pressurized volume. Studies of multidiscipline, R&D growth at the space station involved analysis of a number of scenarios or utilization emphases, each of which assign priority to a particular R&D discipline (e.g., microgravity research, life sciences). Power and other resource requirements were computed for each scenario as a function of lift capability to Station orbit [1], A second evolution option for space station Freedom addresses the accommodation in low Earth orbit of ‘bold’ human exploration initiatives such as those identified by the National Commission on Space and the Ride Report which are undergoing further study of NASA’s Office of Exploration. To support future initiatives such as a piloted mission to Mars or a permanently manned base on the lunar surface, the space station would initially serve as a verification site for mission enabling technology development and life science activities. There, in the precursor phases of the Mars mission for example, research will be performed to better understand the physiological effects of long exposures to zero gravity and to demonstrate and validate countermeasures to adverse effects. To enable future missions of this class, the in-space operation of critical technologies will be demonstrated in the zero-# environment of space station. After the precursor research phase, the station evolves to a transportation node for space vehicle assembly, checkout, servicing and deployment. The electrical power required to support both evolutionary phases has been estimated based upon current understanding of the required operations. Recent results of a NASA, Langley study to establish the needs and define the elements for an early augmentation of SSF post-phase I[z], has identified that 50 kW of additional electrical power should be added soon after assembly complete. This conclusion is independent of evolution path and is driven by the fact that near-term user demand for power far exceeds that which will be available to the users at phase I. Mission Set For analysis of the R&D evolution path, user power and other resource requirements were derived from several sources. The primary source of data was the Space Station Mission Requirements Data Base (MRDB) [3]. The MRDB describes resource needs for near and far term missions partitioned into six categories: US science, technology and commercial payloads and Japanese, European and Canadian missions. These data were updated by the Microgravity Materials Processing Facility (MMPF) Data Base [4], which provides detailed requirements for microgravity research, and the Reference Mission Operational Analysis Document (RMOAD) [5] for definition of life science research facilities. Additional inputs were received directly from the principal investigators when possible. Recently, the SSF Program Office has defined reference missions for the US and international users of space station within their Multilateral Utilization Study [6] (MUS). This information is currently being incorporated into the R&D growth analysis by the authors. Space station requirements for the accommodation of humans-to-Mars and lunar
RkJQdWJsaXNoZXIy MTU5NjU0Mg==