SPS Feasability Study SD76SA0239-2

Figure 3.5-2. Microwave Antenna Trunnion Structure Buildup The outer frame is a 50-meter tribeam, hexagonal structure slightly larger than 1 km between diametrically opposite hexagonal elements. The frame is mounted to the trunnions as shown in Figures 3.6-1 and 3.6-2. The SPS structure fabricating facility assembles the antenna frame at tribeam fabricating sites described in Figure 3.5-2. The crane-way complex transports the frame elements from the fabricating facility to the neutral position plane of the antenna. Cable elements maintain member location during buildup to prevent drifting or excessive loads prior to the final high-strength state inherent in the completed hexagonal shape. Between the 57th day and the 68th day of orbital operations, construction status of the SPS structure and antenna assembly is illustrated by Figures 3.6-3 and 3.6-4. The reference timeline schedule is shown in Figure 3.6-5. Note that the initial wing of the SPS is complete. The blanket fabricating facilities must be transfered to the second wing of the SPS structure. To accomplish this task, at least 1-1/2 bays of structure of the second wing must be assembled. Two methods to transfer the blanket facilities were studied. The first method involved the use of the construction cable complex to tether and transfer the blanket facilities to the new wing, and to provide stabilization and damping of undesired motion by the on-board RCS used to launch from the (Nth-1) satellite and land on the Nth satellite frame. An alternate method involved the use of the satellite relocation system exercising launch and landing orbital operations from wing- to-wing of the same SPS.