1.1 SPS - SYSTEM CONCEPTS (References: 74/1 ,74/3,77/2,77/7,77/9,77/11 ,77/15,77/16, 77/18,78/2,78/3,78/16,78/19,78/27,78/37,78/55,78/63.) 1.1.1 SPS from 1968 to 1979 The first approach in 1968 to imagine a SPS was to attach a microwave antenna to a huge solar array by a cable. The evolution of a photovoltaic SPS configuration is shown in fig. 1.1Fig. 1.1: SPS CONFIGURATION EVOLUTION The philosophy of using concentrating mirrors was to reduce the cost of the solar collector. At the end of this evolution chain (not shown in this figure) was the SSPS-concept of A. D. Little, Grumman, Raytheon and Spectrolab of 1973. This design was the first concept which was investigated deeper (refer to I. 1.2). In 1974 other engineering teams than that around Dr. Glaser started to publish their SPS-imaginations. So Woodcock, Patha, Gregory et. al. from Boeing Co. proposed solar thermal options (refer to I. 1.3). J. Ruth from the Technische Universitat Berlin made recommendations for a high-degree-modularity of the photovoltaic solar collector (refer to 1. 1.4.) . The efforts of the A. D. Little team were continued with NASA’s financial support. A lot of improvements compared to the SSPS- concept were made. At the Boeing and Rockwell companies work continued also and in 1976 NASA found it worthwhile to conduct two inhouse studies. One at MSFC and the other at JSC. The results of these evaluations led to two in depth studies from 1976 to 1978. The one was conducted by Boeing and was managed by JSC (refer to I. 1.5) and the other was conducted by Rockwell and was directed by MSFC (refer to I. 1.6). In 1976/77 a novel concept was published in the USA. It is a gravitationally stabilised photovoltaic power satellite (refer to I. 1.7). In 1977 the responsibility of all SPS-activities was transferred to the ERDA (now DOE) by the U.S.-Congress. A task group was established which defined a "Concept Evoluation" programme. This led to a three year plan of investigations in the field of technical, social, environmental, ecological, and economical aspects of SPS. One of the first milestones of this programme was a reference concent selection in late 1978 (refer to I. 1.8). Note: Technical and cost data on the following 8 pages are received from the literature. The validity of the cost figures was not evaluated in this study.
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