Special Issue on Space Robotics

Since the beginning of space exploration, ""space robots"" have attracted the imagination of many researchers and engineers, and a number of fascinating plans for their use have been proposed.' However, only a few of these ideas have been realized in spite of the early realization that robots would be more appropriate than extra-vehicular activities by a human crew in the hostile space environment. One application is the Space Shuttle Remote Manipulator System, called the ""Canadian Robot Arm"", which has been functioning as expected for more than 10 years. In addition, ROTEX experiments on Space Lab a few years ago demonstrated that advanced robotic technology could perform more complicated tasks on board. It is also reminded that many other robotic experiments were canceled at some stage of their development: In particular, it was hoped that NASA's Flight Telerobotic Servicer would be able to operate with the help of an Orbital Maneuvering Unit. There are complicated reasons for the project cancellations, but one reason seems to be that the maturity level of robotics technology is not high enough; that advanced teleoperation and dexterous manipulation have not reached a sufficient level for practical use. In Japan, most of the space research and development thus far has concentrated on the launching and in-flight operations of conventional spacecraft, so that there has been no real demand for space robots. Recently, however, the Space Activities Committee issued a report on the long term vision for space activities in Japan. In this report, the importance of the use of space robotics technologies for diversified space activities such as space platform servicing, unmanned exploration of Mars and the moon crew support inside the space station, telescience operations, and even for the reusable reentry vehicle HOPE was emphasized. This can be at least partially attributed to the very active research on robotics in Japan, and in turn has encouraged researchers working in these fields. This special issue on space robotics introduces the research activities as several representative organizations, although it does not imply an exhaustive list. Firstly, the activities of two space development organizations are introduced. The National Space Development Agency (NASDA) is responsible for launching and operation this as well as general technology verification. Included in this is the ETS-VII satellite, which as part of its overall mission, will conduct several robotic experiments. The robotic activities of the Institute of Space and Astronautical Science (ISAS) are also outlined. This institution is primarily concerned with scientific missions to the Moon and Mars as well as planets further beyond. Second, the research activities at the national institutes are introduced. These institutes are responsible for supporting national projects at an early stage of development by providing fundamental data and key technologies. This is followed by an introduction to the very extensive research activities at universities across the country. At these universities, space robotics research is pursued not only in aerospace engineering departments but also in other disciplines such as mechanical engineering, control systems, electronics, and information processing. As mentioned before, there are some organizations which do not appear in this special issue. Nonetheless, the coordinator hopes that in Japan, the information given will prove to be useful as in introduction to space robotics research activities in Japan, and further wishes to express his deepest appreciation to all of the contributors.