a. Column/Cable Configuration - The construction approach for the column/cable conf1guration considered a dispersed construction base as illustrated in figure V-A-6-1. Construction begins at the intersection of the six columns. The construction facilities are set up to move out from the center of the SPS array as the trusses forming the columns are manufactured. Operating from the construction facilities, packages of solar cell blankets and concentrators are prepared for deployment, installed along the column and attached to the tension cables at the periphery of the array. Power distribution cable hookups are also made at this point. As the columns continue to grow, the blankets and concentrators are deployed as shown in figure V-A-6-2. Figure V-A-6-3 illustrates an interim array position with the array partially constructed. One of the principal concerns with the column/cable construction is the maintenance of tension in the cables which provide the structural integrity and alignment. Tension adjustments will also be necessary to align to the final geometry. An example of the construction sequence for the column/ cable is shown in figure V-A-6-4. The sequence was developed using the following ground rules: • The construction base (construction facilities, logistics facility, habitat and orbital construction support equipment were primarily assembled in LEO, checked out, then transported to GEO. • Several SPS’s had been completed so the steep part of the learning curve was past and the construction base is available, operational, and sized to meet the required rate of construction. • Construction time of one year. • Antenna subarrays fabricated in LEO and transported in GEO for installation on antenna structure. • SPS configuration is 10 GW, POP oriented, column/cable structure. In order to estimate the number and type of machines needed for construction, construction analysis sheets were prepared. Tables V-A-6-1 thru V-A-6-4 are examples for the column/cable buildup for the construction steps outlined in figure V-A-6-4. A summary of the amount of construction equipment is given in table V-A-6-5. Construction on the antenna originates from a construction facility attached to two of the column construction facilities. A description of the antenna construction concept is provided after the discussion of the truss configuration buildup.
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