The final selection of a construction site (LEO, GEO or combined) depends on many factors. A summary of advantages and disadvantages is shown in fig. 2.6.5. The Boeing team chose a concept with module construction in LEO (8 Modules»1 SPS), electric self propulsion into GEO, and there the final assembly of the power satellite. For this SPS concept this method is considered to offer the greatest potential mainly because of the expected significant savings in transportation cost ( 30 %). This concept requires very large construction bases: LEO: 2.9 x 1.8 x 1 km, 5.6 million kg weight GEO: 1.6 x 1.4 x 0,1 km, 0.9 million kg weight. The Rockwell concept and the DOE/NASA baseline concept chose total construction in GEO mainly because of lower structural loads and therefore lighter structure. A Grumman study says, that the size of a construction base depends mainly on the number of satellites to be mounted per year. 1.2.7 Programme Cost and Risk (References: 76/1,76/2,76/3,76/4,76/6,76/7,76/8,76/9,76/10, 77/3,77/9,77/10,77/11,77/14,77/16,77/17,77/18,77/19,77/24, 77/25,78/2,78/7,78/11,78/13,78/16,78/24,78/34,78/35,78/44, 78/48,78/54,78/57,79/2,79/3.) I.2.7.1 General This category implies critical cost/risk areas evaluation, cost ranging of the overall SPS system and sub-systems (including transportation systems) and cost estimates of full duration programme phases. 1.2.7.2 Critical Cost-Risk Areas Several areas of SPS design, development and implementation concerns have been yet identified, which will remain uncertain due to cost for many years along the DDT&E phase. The most risky ones - i.e. the most sensitive to SPS overall cost - are meant to be the following: - Space transportation cost and its sensitivity concerning construction site location of SPS - Solar cell cost and efficiencies - Rectenna site and construction cost (land use, local environmental and structural impacts, or offshore base construction) - Costs by environmental impacts (acquisition of atmospheric/ ionospheric environmental standards, - of RFI standards on earth and in space, - of surface radiation density standards, etc.)
RkJQdWJsaXNoZXIy MTU5NjU0Mg==