every habitable space there must be at least two means of egress; and depending on the degree of failure, the egress to where and in what time frame may vary, i.e., partial or total evacuation. (A more detailed discussion will follow the description of the internal component spaces.) Construction Methodology. The construction methodology is to construct the components intact on Earth, transport them via the Shuttle to LEO, and assemble on site. Every piece of SPORE was designed to satisfy the spatial and weight limitations required of payloads to be transported within the cargo bay of the orbiter. Care was given to design parts to minimize the quantity of construction performed in this alien environment. All joints will be designed with simplicity paramount therefore minimizing the complexity of movements needed for assembly by the construction crews. Modularization will be optimized, also affording simple repeated connections. The configuration will be constructed from the central Og hub radially outward. (See Figs. 3, 4, and 5, discussions of which will follow.) This will allow the invaluable manufacturing in three of the four Og environments to commence as soon as possible, helping to pay for SPORE even before it is made completely operational. Structural Stability and Integrity. SPORE must be dynamically stable. The centrifugal forces induced by the 2 rpm rate of rotation produce the pseudogravity experienced in each of the components, in turn dependent upon the distance from the axis of rotation/center of gravity of the facility. The structural design resembles in plan a triangulated spider's web; and in section it resembles a bicycle wheel. The central axis, the tips of which function as the primary orbiter docking points for the facility, is a double prestressed king post held in compression by the tension cables. The so-called blades, or spokes, are elevator shafts and are predominately nonstructural members. It is important to bear in mind that the structure gains its rigidity from its spinning motion and that during assembly, i.e., at rest, the structure is flexible; the cables will not be in tension and the components will float and drift. However, in the vacuum of space, the components will be held from drifting into the center or each other by the elevator shafts and the cables. Failure of any structural member must not permit peril, and the most critical time is during system initialization. It can be shown that the dynamics of the structural system at start-up are highly nonlinear having infinitely many degrees of freedom; however, the geometric configuration, which was based on static analysis, contributes significantly to the minimization of the nonlinear characteristics of the structure. (During start-up, the ship will not be inhabited and the Shuttle will not be docked. Once stable, docking will be accomplished by synchronizing the yaw of the Shuttle to that of the ship and then docking by translation. This would then avoid the need to spin down the ship each time docking by the Shuttle occurs.) Program Goal. The goal, to further research and development in the direction of establishing the meaning of and means to ensure the integrity of closed-loop environments in space-optimized pseudogravitational conditions, must be allowed and encouraged to progress by the design of the facility itself. Financial Considerations. Each design decision must answer, At what cost relative to the gain? The greater the induced pseudogravitational force, the more expensive the environment is to produce and maintain, because the structural members must be stronger/larger/heavier. Bearing in mind that each piece must be transported to the
RkJQdWJsaXNoZXIy MTU5NjU0Mg==