Masato Adachi

Sampling of Regolith on Asteroids Using Electrostatic Force

AbstractThe authors have developed an electrostatic force–based sampler to reliably and autonomously sample asteroid regolith. After applying a rectangular high voltage between parallel screen electrodes mounted at the lower end of a tube, the resultant electrostatic force acts on nearby regolith particles. Some agitated particles are captured when passing through the screen electrode openings and transported to a collection capsule through the tube. In a microgravity environment, effective particle sampling was expected because particle motions are not affected by the negligible gravitational force. The authors confirmed the sampler’s performance in a microgravity environment through numerical calculations and a model experiment. The calculation using the distinct element method predicted successful regolith capture, including conductive and insulative particles, under air and microgravity. The sampler shows much better performance in vacuum than in air. Lunar regolith simulant was sampled experimentally...

Utilizing Electrostatic Force and Mechanical Vibration to Obtain Regolith Sample from the Moon and Mars

Abstract To realize reliable and autonomous sampling of regolith on the Moon and Mars, the authors have developed a unique sampling system that employs electrostatic force and mechanical vibration for the capture and transport of particles. A high alternating current (ac) voltage is applied between parallel screen electrodes mounted at the end of the sampling tube. Regolith particles on the surface of the Moon and Mars are captured using an electrostatic force, and they are passed through the openings of the screen electrodes. The captured particles are then transported through a tube to a capsule against gravity utilizing mechanical vibration. Experiments demonstrated that regolith is captured for a short time period if the open end of the sampling tube is immersed in the regolith layer. The captured regolith is transported upward through the inclined sampling tube against gravity. However, if the regolith in the vicinity of the fixed tube is depleted, the transport rate is decreased. The regolith partic...

Sampling of regolith from asteroids utilizing magnetic force

The authors have developed a magnetic sampler for the future sample return missions from asteroids. The sampler employs only a solenoid coil, DC power supply, and a simple switching circuit. The system is simple and has no mechanical moving parts, thus, making it highly reliable. In the present study, the authors analyzed a particle dynamics, and evaluated the sampler performance by conducting experiments and numerical calculations. The experimental and numerical results qualitatively agreed with the analytical calculations, and these indicate that the particle movement depends on the interaction of the electric current and its applied time. Moreover, the performance in space environments, such as vacuum and micro-gravity of 0.00001-G, are predicted by using numerical calculations. The calculation results show the space environment would make the sampler performance improved.

Novel Social Innovation Concept Based on the Viewpoint of the Infrastructure User

Recently, due to the deceleration of the markets in developed economies, the growing demand for infrastructure development in emerging countries has become more important in the global economy. Conventionally, developed countries have improved their infrastructure from governments and suppliers viewpoints. However, this approach has not always been the best when working in emerging countries. In this study, we propose an innovative approach inspired by the concept of social innovation, centered around the social viewpoint. It consists of a system for the successful implementation and sustainable development of new infrastructure projects in emerging countries. We focus on an ongoing railway project in Vietnam by looking at the applicability of this concept there. Finally, the concept is evaluated through rounds of discussion with experts from the government, academia and industry. It was concluded that the project is perceived to have great potential for the region, and it is regarded with high esteem by all stakeholders.

Electrostatic particle-size classification of lunar regolith for in-situ resource utilization

To realize long-term lunar exploration, it is essential to develop technologies such as drilling, extraction, and chemical processing of lunar soil to achieve in-situ resource utilization (ISRU). Classification of particle size is one of the most important technologies required for ISRU. Because conventional techniques that utilize air flow and require high power are not suitable for operation on the Moon, the authors have developed two new technologies for electrostatic particle-size classification utilizing the balance between the electrostatic force and gravitational force. Our experiment demonstrated that particles less than 20 μm in size could be efficiently separated from the bulk of the regolith. Numerical method that can predict the performance in the lunar environment has been developed based on a threedimensional Discrete Element Method.

Magnetic Sampler for Regolith Particles on Asteroids

AbstractA magnetic sampler for future sample return missions on asteroids was developed. The sampler had a simple configuration, consisting of a solenoid coil, direct current (DC) power supply, and...

C06 A numerical simulation for sampling of particles from asteroids utilizing alternative electrostatic force considering dielectrophoresis

Laplace transforms are an essential part of the mathematical background required by engineers, mathematicians, and physicists. They have many applications in physics and engineering (electrical networks, springs, mixing problems; see Sec. 6.4). They make solving linear ODEs, IVPs (both in Sec. 6.2), systems of ODEs (Sec. 6.7), and integral equations (Sec. 6.5) easier and thus form a fitting end to Part A on ODEs. In addition, they are superior to the classical approach of Chap. 2 because they allow us to solve new problems that involve discontinuities, short impulses, or complicated periodic functions. Phenomena of “short impulses” appear in mechanical systems hit by a hammerblow, airplanes making a “hard” landing, tennis balls hit by a racket, and others (Sec. 6.4).