CHAPTER 2 R&D by Research Organizations The Institute of Space and Astronautical Science [ISAS] 1. Introduction Basic research generally occurs at universities and attached research organizations administered and financed by, but relatively independent from, the Ministry of Education, Science and Culture (MOE). Several National Inter-University Research . Institutes with their own research staff and facilities report to the MOE. One of such institutes, ISAS (the Institute of Space and Astronautical Science), is responsible for the Japanese Space Science Program under the coordination of the government Space Activities Commission (SAC). ISAS cooperates with NASDA (National Space Development Agency of Japan) and other government agencies on interagency space projects, such as the SFU free flyer project 2. Previous SPS Research Previously, mainly researchers at universities were interested in the scientific aspects of the SPS. Their activities included three topics: microwave technology for rectenna design; microwave interaction with the ionosphere; and concept studies including proposals for the space station mission. (1) Rectenna Design Two research groups worked on rectenna design using Grant-in-Aid for Scientific Research from the MOE One group lead by Adachi studied optimization of the circular antenna aperture illumination to achieve the maximum transmission efficiency with constraints on the radiation levels at the edge of the receiving antenna aperture and at the radiation peaks of the subsequent sidelobes. Another group led by Itoh studied the application of the microstrip antenna instead of the linear antenna for the SPS rectenna to suppress the higher harmonic reradiation which might cause interference with communication (4). (2) Rocket Experiment One problem area anticipated for the SPS was the phenomena caused by interaction between the intense microwaves transmitting power from space to the ground and the ionosphere. The sounding rocket experiment. MINIX. was proposed by Matsumoto Fig. 1. Preflight radio test The photo shows the inflight configuration of the MINIX experiment with the hanging daughter unit separated from the mother unit and the recovery section on the ground. The ISY METS rocket experiment will be an updated version of this experiment. and Kaya in 1978 and adopted in 1980 by the ISAS Space Science Committee as a scientific payload on a sounding rocket, and was flown successfully in 1983. Fig. 1 shows the prefiight test of the experiment (3) Concept Study The U.S. satellite power system study and planning for the Space Station provided Japanese researchers in various fields with an opportunity to consider their research from the perspective of space. The Space Energetics and Environmental Laboratory (SEEL) was a typical example of group effort, dedicated to space energy exploitation
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