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Nakamori et al. found experimentally that the friction between a partly polished diamond coating and a metal surface was drastically reduced to zero as relative speed increased to a few m/s [Diamond Relat. Mater. 14, (2005), 2122]. It seems that diamond coating took off the counter surface because sliding was noiseless in their experiment. However, the mechanism of this phenomenon was unknown. In the previous work, we performed the numerical simulation of micro‐/nanoscale gas flow between two sliding surfaces, i. e., the slider surface with microscale surface roughness like partly polished diamond coating and the flat counter surface. And then, we successfully reproduced lift force large enough to suspend the slider used in the experiment and found that this effect became notable only for micro‐/nanoscale gas flow. In the present paper, we investigate the effect of configuration of micro‐/nanoscale structure on sliding surface on molecular gas‐film lubrication. Since micro‐/nanoscale gas flows between two...

Nakamori et al. found experimentally that the friction between a partly polished diamond coating and a metal surface was drastically reduced to zero as relative speed was increased. It seems that diamond coating took off the counter surface because sliding became noiseless. This phenomenon shows the possibility of innovative air lubrication system. In the present work, we make the floating mechanism clear by using the direct simulation Monte Carlo (DSMC) method. It is found that the phenomenon is peculiar to the high Knudsen number flows.

We propose a new concept controlling a satellite by a fiber laser loaded in it and demonstrated the acceleration of pendulum with 7kW/2n and 2kHz fiber laser, and measured the Cm of 16Ns/MJ corresponding to the scaling of YAG laser. This laser can be easily bundled to generate much larger power. For more efficient acceleration, we propose “metal‐free water cannon target”, the new concept of propulsion using only water. The momentum coupling coefficient of 2500[Ns/MJ] was achieved with vacuum pump oil instead of water, and we succeeded in controlling the driving direction by the system based on the new concept. This can be used for thrusting a satellite and controlling its posture in combination with fiber lasers.

We found that water overlay on a metal layer is more effective than solid overlay. By using this target we demonstrated the successful flight of paper‐airplane of 5 cm‐size over a distance of 1–2m. In this paper, repetitive water supply system and levitation system are proposed for practical application, and examined by experiments. We succeeded in driving an object continuously using repetitive water supply and air slider. We also succeeded in driving 300g object by 0.5J laser using these equipments. In this paper, we try to find out a new possibility of water‐powered laser propulsion.

In this paper, we report experimental demonstration of propulsion of 100‐weight object with only 668mJ/5ns YAG laser. This is made possible by water overlay structure and the effort to reduce the friction by putting the object on water surface or using a levitating system which we call on “air‐slider”. Furthermore, several water supply systems provided the repetitive propulsion. In addition, we found the laser‐driven micro‐turbine would provide an interesting application area in driving micro‐obstacle.

In previous papers, we reported the successful flight of paper‐airplane‐about 5 cm‐size [1]. Since then, we try to find out a new possibility of the laser propulsion that uses overlay structure especially using water leading to high efficiency [2]. In order to this concept in high altitude, we need to insulate the water layer from vacuum, otherwise water will be evaporated or freeze in vacuum condition. For this purpose, we here propose an “air curtain”. We have done simulation and experiments on this concept. Furthermore, we examined in detail the various features of water exotic target by pendulum and semi‐conductor load cell. The coupling coefficient and specific impulse are discussed both by simulation and experiments.

In previous papers, we reported the successful flight of paper‐airplane about 5 cm. Application of such micro‐airplane to CO2 measurement and tornado observation is proposed. For practical application, repetitive water supply system and levitation system are proposed and examined by experiments. The latter can also be used for launching waste of nuclear reactor and structural materials for space station. Some future applications like stratospheric airplane and microship in human blood vessel are discussed.