When operating space robots, safety and reliability are the most important issues-even at the expense of dexterity and swiftness. This makes it very stressful for operators to teleoperate space robots, especially since they cannot be repaired during operation, unlike ground robots. Furthermore, operators have to quickly analyze a large amount of information about the target objects and immediately make decisions on how to proceed. The majority of this information is presented visually, including digital values, status displays, 3D computer simulation, and camera images. Therefore, we developed an audio feedback system that can convey some of this information in order to improve the operator's decision-making and avoid accidents. We used an eye-mark-recorder to assess the performance of this system. Audio systems for information presentation have previously only been proposed for ground-based operation systems. This is the first case in which sound has been utilized for space robot operation, even though sound does not actually exist in space.

This paper discusses system and technology aspects crucial to the development of satellite communications at Ka band (20-30 GHz) and beyond. It surveys the evolution of Ka band geostationary Earth orbit (GEO) satellite communications until the present stage of development of systems for direct-to-user (DTU) provision of interactive multimedia services worldwide. Then it discusses the attenuation problem and main technical issues of this new technology. Finally, it provides a view on experiments and technological developments at extremely high-frequency (EHF) bands.

Japan now operates the communications satellite CS-2. A test communications satellite, CS-1, was launched in 1977, and CS-3 will be launched in 1988 as a successor to CS-2. On the other hand, in the area of mobile satellite communications development, Japan is proceeding with an experimental program; ETS-V/EMSS (Engineering Test Satellite-V/Experimental Mobile Satellite System), for which a satellite will be launched in 1987. A follow-on experimental ETS-VI program is planned and will be launched in 1992 as a 2000-kg weight class satellite. Japan has also begun an Experimental Platform Study as a step toward the Geostationary Communication Platform. This paper reviews and explains the scenario, activities, and objectives of satellite communications development in Japan.