This paper proposes a three-dimensional aerial projection device, All-Round Accommodator, with rich reality using Peppers Ghost and variable focal length lens. In order to achieve improvement of rich reality of aerial projection, our proposed device incorporates two factors of motion parallax and accommodation. The former achieves all-round view by using the property that the pepper's ghost can be observed from many directions. We can perceive three-dimensional effect when projection is moving. The latter is achieved by combining a volumetric display and a variable-focal lens. An advantage of accommodation is to realize three-dimensional reality even when projection is not moving, i.e., still. In order to prove our system is feasible, a prototype zero for demonstration has been designed, implemented and experimented if we can feel three-dimensional effect from aerial projection. Experimental results have shown our principle performed properly.

In this paper, the authors present an intelligent lure which can avoids rooting by applying a disturbance observer (DOB). This environment-friendly lure has a propeller motor for backward motion. We make a better use of this motor to classify the lure's motions into sinking, being drawing, and hitting something according to a time-series of DOB estimates. Its prototype has been implemented and its ground experiments have been conducted. Experimental results prove we have extrapolated the lure's motions successfully.

A compact detector array with a symmetrical structure was designed and developed for the measurement of fast neutron flux in space radiation environments by the recoil proton method. It consists of seven solid-state detectors and a hydrogen-containing conversion layer, which can effectively eliminate the background from the charged particles and gamma rays. The performances for fast neutron measurements in the low Earth orbit and on the lunar surface have been simulated by Geant4 software. The signals from recoil protons can be well distinguished in a complex radiation environment. The accuracy of fast neutron flux measurement can be improved with a higher signal-to-noise ratio. Utilizing this array, a neutron spectrometer for low Earth orbit applications was constructed and was launched on board the “Weiming-1” CubeSat at the beginning of 2024.

This paper presents a remote control between a haptic feedback control stick and a wheel of a two-parallel-wheeled rover. It is well-known that the operator's operability was improved largely by haptic information reproduced on the stick using the bilateral control. This haptic information corresponds to disturbance force/torque applied to the wheel of the rover. When the disturbance is estimated using the disturbance observer (DOB), its estimated value includes not only an external force, viscous resistance, Coulomb frictional force, and a force by a modelling error, but also a restoring force. The restoring force is a force occurring when an operating-operated robot system is synchronized by a position control. It often becomes a problem of the bilateral control using two robots with a dynamically-different structure. Particularly, our experimental system in this paper has a very large dynamical difference. In other words, there exists a fairly-large time delay between them. The DOB of the operating robot estimates a value including this restoring force. Intuitively, this seem to prevent the operator from feeling sensitively other forces applied to the wheel such as the external force. However, on the same time the authors think this restoring force is very important for the operator to know situations of the remote rover, e.g., whether it drives with the speed given as a command value or not. In this paper, we proposes a positional gain adjusting bilateral control method in order not to prevent the restoring force from feeling the external force and so on. The proposed method was experimented for verification. Experimental results were discussed and evaluated comparing to the following two cases: one is when a positional gain of the operating robot is reduced as the difference increases, and the other is when that of the operated robot is enhanced contrarily as the difference increases.

This paper presents development of a 2DOF haptic feedback control stick for remote control of a two-parallel-wheeled rover. In bilateral control, when dynamics are quite different between a leader and follower devices, e.g., between a linear-slider type of control stick and a wheel with a comparatively large moment of inertia, a force reproduced on the control stick based on external forces applied to the rover’s wheel, is disturbed largely. Since the position control forces the control stick’s position and the rover’s angular velocity to be synchronized, the operator feels not only the reproduced force but also a force by this position control inevitably on the same time. We call this force a restoring force. The restoring force disturbs the operator to feel the reproduced force accurately. But the authors think the restoring force is meaningful for remote navigation of the rover as another haptic information. Thus, in this paper, we developed a 2-DOF haptic control stick, which transfers the reproduced force and the restoring force separately to a slider and a grip, and proposed a control method for achieving this purpose. The control stick was implemented and was performed successfully in verification experiments using the proposed control method. Experimental results were discussed comparing to the former 1-DOF control stick.

Drones, whose applications have been rapidly expanding in recent years, have a wide range of uses, such as transporting goods, spraying pesticides, inspecting structures, and even flying cars, which have become a hot topic in recent years. However, it is difficult to fly in bad weather such as gusty winds. To solve these problems, flight stability has been controlled by manipulating the rotation speed of the propeller. However, it is not desirable to use a propeller for flight stability in bad weather conditions. Therefore, the authors developed a drone equipped with a CMG(Control Moment Gyro), which has the property of rotating in a direction perpendicular to the force applied to the axis of rotation from the outside, and confirmed the suppression effect of pitch angle fluctuation through experiments. In this paper, based on these findings, we developed and tested a drone equipped with two CMGs that can suppress the variation of pitch and roll angles. As a result, the variation of pitch and roll angles without CMGs was 20 degrees and 25 degrees, respectively, while the variation of pitch and roll angles with CMGs was 12 degrees and 16 degrees, respectively. In the case of the CMG, the pitch and roll angles fluctuated by 20 and 25 degrees, respectively. In addition, it is necessary to operate the controller to keep the drone as level as possible before applying disturbance, and we confirmed that the variation of pitch angle and roll angle with CMG is less than that without CMG.

The spontaneous polarization of pyroelectric crystal is utilized to X-ray emission in low pressure gas of ~1 Pa, which has a potential as a future in-situ X-ray source with small size, light weight, and low electric power consumption. The pyroelectric X-ray production still has problems as its intensity and reproducibility because the mechanism of electron production is still an open question. We have experimentally and numerically evaluated pyroelectric X-ray generation relevant to electric discharges around the pyroelectric crystal with various sizes of target support and target with/without a needle. Three kinds of electric discharge, between crystal top and metallic target (CT-MT discharge), between crystal top and crystal bottom (CT-CB discharge), and along with crystal surface (CS discharge), were observed. The CT-MT discharge was measured by the 1 cm × 5 cm target support or target with a needle, which induced irregular X-ray increases. X-ray intensity became reproducible, but not so large when the CT-MT discharges were measured. The CTCB and CS discharges were active for the large target plates. These two discharges occur irregularly, resulting low reproducibility. While reduction of crystal potential by the CS discharge was not large, the CT-CB discharge stopped Xray emission. When the CT-CB was not measured, the X-ray intensity became large. Calculation results of electric fields at around the crystal supported the experimental results, which implied that selection of appropriate target support is one of important factors to obtain large and reproducible X-ray intensity by the pyroelectric X-ray generation.

This paper develops a haptic feedback control stick for remote control of a two parallel wheeled rover. The authors apply a bilateral controller for this remote operating-operated system in which their structures are different. Thus, the developed haptic feedback control stick plays a role as not only an input device to give the velocity information to the system but also an output device by which the operator feels an estimated external force applied to the wheel of the rover. The haptic feedback control stick is strongly expected the operator can control the operated rover more intuitively and more safely. In this paper, the authors experimented by combining a linear-slide-type control stick and a single wheel computer simulator of the rover. However, the operator felt a force except the estimated force to the rover's wheel, in conditions that a time delay occurred because of a large dynamical difference between the control stick and the rover. Therefore, two types of experiments were compared, i.e., one used only the bilateral control and the other used switching the bilateral control and the force control according to a value of the time delay. These experimental results were discussed and evaluated as focusing on a situation when a time delay occurred.

The performance of pyroelectric X-ray generator (PXG) under high vacuum (down to 2.2 × 10-5 Pa) is investigated with two different gases of dry air and N2, in order to develop a high-intensity X-ray generator. For both gases, the X-ray intensity decreases for pressures less than 1 × 10-4 Pa. It is required to control appropriate inner-gas pressure (1 - 10-3 Pa) to obtain high X-ray intensity, when PXG is used as an active X-ray source for future planetary exploration missions. Furthermore, an analytical system with a carbon nanotube X-ray generator is also discussed for light-element measurement.

Lunar meteorites provide information about areas of the Moon not sampled by the Apollo and Luna missions, so they can be used as more-representative geochemical datasets for evaluating global lunar evolution. However, the launching craters remain unknown for many lunar meteorites. This paper, therefore, aims to identify the launching sites of lunar meteorites with remote-sensing datasets. This work focuses on one lunar-meteorite group, the Northwest Africa 773 (NWA 773) clan, which has the very-low-Ti basaltic composition and one of the youngest crystallization ages (similar to 3 Ga) among the lunar basaltic meteorites. We investigated the source of the NWA 773 clan by comparing their geochemical compositions and geochronological information with the following remote-sensing datasets: 1) the Lunar Prospector gamma-ray elemental maps (FeO, TiO2, Th) and the SELENE gamma-ray elemental maps (CaO), 2) the surface ages determined from imaging data by using the cratercounting method, and 3) high-spatial-resolution maps of the FeO and TiO2 and spectral-ratio images made from the SELENE multi-band imager data. From these comparisons, the NWA 773 clan is most likely to have originated from the north part of Mare Imbrium inside the Procellarum KREEP Terrane (PKT). Furthermore, the eruption age of surface basalt surrounding the Le Verrier D crater in the north part of Mare Imbrium between 3.0 and 3.3 Ga, and the formation of the Le Verrier D crater, are consistent with the duration of igneous activity and timing of meteoroid impact of the NWA 773 clan. There is a fresh crater with bright ejecta on the edge of the Le Verrier D crater, and it is possibly the young launch crater of this meteorite group.

A liquid crystal (LC) lens can make any lens state from positive (convex) to negative (concave) by applying an external voltage. However, when the LC lens changes its focal length, it is difficult to say its response time is fast enough. In this paper, the authors aim at making the response time of the LC lens be shorter by using a control theory to a value of the external voltage applied to the LC lens. We constructed an automatic control system which can change the focal length faster by a computer program. The computer program gives appropriate effective values of AC voltages with the LC lens based on a feed forward control. We conducted experiments to change the focal length of the LC lens from a non-lens state to 200mm and -100mm, respectively. When our proposed effective voltage control method was performed, the response time was successfully reduced in half, compared to a case when a simple step-like voltage was applied.

This paper aims at reducing enormous data amount of color point cloud measured from a 3D-LIDAR sensor by combining with a visible-ray color camera. A huge data amount of the points often keep us away from saving the data storage device and computing by a real-time processing. In this paper, the authors propose a measurement system, i.e., Space-variant Color Point Cloud Measurement System, in order to achieve enormous data reduction. A 2D-LIDAR sensor and a stepping motor are combined (i.e., playing a role of the 3D-LIDAR sensor) to compose a proto-type of our experimental device. A space-variant color point cloud generation method is also proposed using the above measurement system. The region of interest (ROI) map, generated from the saliency map of the input image from the CMOS color camera, plays an important role for the data reduction in our proposed method. This paper explains also how a pixel with RGB color data in each input image corresponds to each of the distance data, by paying attention to a disparity calculated from the distance. Experimental results proved good performance of data reduction using our proposed method by 60.59 percent and 40.82 percent in different reduction conditions compared to the original data amount, respectively.

The lunar surface is directly and continuously exposed to Galactic Cosmic ray (GCR) particles and Solar energetic particles (SEPs) due to the lack of atmosphere and lunar magnetic field. These charged particles interact with the lunar surface materials producing secondary radiations such as neutrons and gamma rays. In a departure from precise GCR and SEP data, we estimated the effective dose equivalent at the lunar surface and in a lunar lava tube in this paper by using PHITS, a Monte Carlo simulation tool. The effective dose equivalent due to GCR particles at the lunar surface reached 416.0 mSv yr-1 and that due to SEPs reached 2190 mSv/event. On the other hand, the vertical hole of the lava tube provides significant radiation protection. The exposure by GCR particles at the bottom of the vertical hole with a depth of 43 m was found to be below 30 mSv yr-1 while inside a horizontal lava tube, the value was less than 1 mSv yr-1 which is the reference value for human exposure on the Earth. We expect that the lunar holes will be useful components in the practical design of a lunar base to reduce radiation risk and to expand mission terms.

An igneous clast from the Northwest Africa 773 (NWA 773) clan of lunar meteorites formed by silicic volcanism on the Moon. The clast was identified in Northwest Africa 2727 (NWA 2727), which is included in the NWA 773 clan. Over 80 mode% of the clast consists of silica + plagioclase + K-Ba-feldspar. The silica phases cristobalite, tridymite, and quartz are all present in the clast, indicating rapid cooling at low pressure in agreement with a volcanic setting. This clast is characterized as a dacite on the basis of mineral modes and whole-rock chemical composition. Olivine and pyroxene in the clast have high Fe/Mg ratios (olivine Fe# > 99, pyroxene Fe# > 99; with Fe# = molar Fe/(Fe + Mg) × 100), suggesting crystallization from a residual liquid after fractionation of more magnesian silicates. The clast is similar in some respects to ferroan gabbro alkaline-phase-ferroan (FG/ARFe) clasts that are inferred to be co-magmatic with olivine gabbro (OG) and other mafic lithologies of the NWA 773 clan. However, the high silica concentration and dominance of apatite as the main Ca-phosphate (no merrillite was identified) are distinct from the FG/ARFe clasts. Thus, the dacite clast probably crystallized in a magmatic setting that was independent of the OG and FG/ARFe lithologies. The mafic major element composition, young age, and high KREEP-content of the NWA 773 clan have been used previously to infer an origin from the Procellarum-KREEP terrane (PKT) on the nearside of the Moon. Several candidates for silicic volcanism/plutonism have been identified in the PKT (e.g., Gruithuisen Domes, Hansteen alpha, Lassell Massif). The presence of the dacite lithology provides additional support for an origin in or around PKT for meteorites of the NWA 773 clan, and for complex igneous activity in PKT region.

The electron mobility and longitudinal diffusion coefficient were measured in high pressure xenon doped with hydrogen at a pressure of 1.0 MPa and H2 concentrations of 0.1%, 0.21%, and 0.42%. The density-normalized longitudinal diffusion coefficient was found to increase in Xe + H2 gas mixture with increasing H2 concentration. However, the variation in the magnitude of longitudinal diffusion was not significant with doping H2 gas. The scaling rule for electron transport parameters in gas mixtures would be applicable to the mobility and longitudinal diffusion coefficient for the high reduced electric field.

In this paper, the authors propose a visual remote operation system of the vehicle type of mobile robot for lunar exploration, i.e., the low-gravity planet rover. This rover has a unique mechanical part to shift its center of gravity, namely COG shift box, for its high-speed and stable driving. High-resolution Wide Angle Fovea (WAF) sensor, equipped on the rover, characterizes our proposed visual remote operation system as follows: (1) High-Resolution WAF sensor provides the operator with enough wide-angle field of view (FOV) to achieve safe navigation of the rover. (2) The view direction control of High-Resolution WAF sensor, by the eye-tracking device embedded on HMD, enables the operator to observe targets, to which he/she should pay attention, more in detail in order to make his/her better decision of navigating the rover. In addition, by displaying images remapped from the input image of High-Resolution WAF sensor, we expect to solve the bottleneck problem of data transmission. (3) The input image from High-Resolution WAF sensor is also applied for autonomous navigation of the rover.

Electron multiplication in high-pressure pure xenon was studied in the 0.5–3.0 MPa pressure range using a cylindrical proportional counter. The electron multiplication factor and the first Townsend ionization coefficient were determined, thus expanding collective knowledge beyond the previous studies, which were limited to 1.0 MPa. The measured electron multiplication factor falls between 15 and 2400 for the investigated pressure range. The density-reduced first Townsend ionization coefficient in this work is larger than that obtained for low-pressure xenon. In addition, the density-reduced first Townsend ionization coefficient was found to be density dependent. It was also found that the energy resolution deteriorates with increasing pressure. However, when the electron multiplication factor is several hundred, the energy resolution in high-pressure pure xenon was found to be better than that in commonly used xenon-based gas mixtures.

The water-ice at the lunar polar regions is important from the viewpoint of scientific interest and future lunar utilization. According to some theoretical suggestions, water and other volatiles could be delivered to the Moon by comets and/or the solar wind, and they might be accumulated and trapped at cold spots as the permanently shadowed areas. Although several remote observations have indicated the presence of water-ice in lunar polar regions, its abundance and spatial distribution are still controversial issues. Recently, in Japan and other countries, lunar landing explorations at the polar region are being studied in order to obtain the abundance and distribution of water in the subsurface and to reveal the accumulation mechanism of water. The neutron spectroscopy is one of the best methods for in-situ water detection on the airless planetary surface. The galactic cosmic rays generate fast neutrons via nuclear spallation interaction in the subsurface materials at a depth of several tens centimeters. Then the fast neutrons are moderated to thermal and epithermal neutrons by interactions with subsurface materials, and this process is terminated at the thermal neutron capture or leakage of neutrons from surface. Since the hydrogen atom has a large elastic scattering cross section for a neutron and a nearly identical mass as a neutron, the neutrons are efficiently moderated by the elastic scattering with hydrogen atoms. Therefore, the leakage neutron flux strongly depends on the hydrogen abundance as well as the chemical composition of surface materials. investigated generated by galactic cosmic rays were calculated for different hydrogen abundance in the lunar polar material. The dependence of neutron fluxes on the spatial distribution of hydrogen were also studied on the several patterns of distribution. In addition, the neutron detection efficiency was estimated by assuming multiple neutron detectors in order to select and optimize the neutron spectrometer. An Li-glass scintillator, a B-loaded plastic scintillator, and a 3 He proportional counter were considered as neutron detectors. The preliminary calculation results will be presented, and the detection capability of water on the lunar landing exploration will be discussed.