Solar Power Satellite: Effects of Microwave on Biological and Ecological Systems

Abstract

Space energetics has been assigned to a major field of engineering science in space. It relates to important components of infrastructure for future utilization of space and its civilization. Solar Power Satellite (SPS) is one of targets which will be developed in the next century. This project concerns with energy environment problems on earth. Solar power is converted to electric power on orbit and transmitted to ground. This "clean" energy is supposed to eliminate global change of atmospheric environment caused by the usage of fossil fuels. The green house effects at increased carbon dioxide concentration will bring catastrophic change of thermal structure in atmosphere near future. Key technologies for SPS is now planned to be developed. The project named Space Energetics and Environment Laboratory (SEEL) was proposed to be implemented on the space station, now on a free flyer, SFU. SEEL is composed of several experiments, such as Space Plasma, Electric Propulsion, Space Radar, Microwave Power Transmission, and Space Laser.Deployment and dynamical control of large structure in space, electric power generation by solar heat engines, and many related experiments make up a technology package for space energetics. Among these experiments listed above, evaluation of environmental effects caused by SPS is an important part of our study. Working group on SPS was established in ISAS last year. It organizes research programs relevant to SPS development. One of subgroups of this working group is dedicated to ''Biology and Ecology". Programatics of Japanese SPS, macroeconomic aspects and other issues of SPS have been discussed at ISAS Space Energy Symposium and other places. Assessment of SPS was once performed by DOE and NASA. Points of finding and needs of further studies were described in their reports published under the name of SPS Concept Development and Evaluation Program. With their reference system, biological and ecological systems are exposed to microwave radiation. Biological effects of microwave radiation are not well known. Safety standards for exposure of man under high frequency electromagnetic fields differs in many countries.Mechanism of microwave acting on biological organisms has been remained to be answered. Methodology of risk assessment for long term exposure with weak microwave should be also established. It is suggested to promote systematic research on the biological and ecological effects of microvave. In societal assessment, there are several problems which originate in nationality. Siting of rectina in Japan might be offshore, because of its small land area and high population density. Such a domestic features should be also considered in our study. Involvement of biologists is strongly requested at the beginning of Japanese SPS project. Their participation is important to break down work and to define requirements for the activity of SPS working group. On the other hand, SPS might open another curiosity of biologist on interaction of electromagnetism and living systems.