Optimization of Return Trajectories for Orbital Transfer Vehicle between Earth and Moon

In this paper, optimum trajectories in Earth Transfer Orbit (ETO) for a lunar transportation system are proposed. This paper aims at improving the payload ratio of the reusable orbital transfer vehicle (OTV), which transports the payload from Low Earth Orbit (LEO) to Lunar Low Orbit (LLO) and returns to LEO. In ETO, we discuss ballistic flight using chemical propulsion, multi-impulse flight using electrical propulsion, and aero-assisted flight using aero-brake. The feasibility of the OTV is considered

Effect of atomic-hydrogen irradiation on reduction of residual carrier concentration in β-FeSi2 films grown on Si substrates by atomic-hydrogen-assisted molecular beam epitaxy

β-FeSi2 films were epitaxially grown by atomic-hydrogen-assisted molecular beam epitaxy (MBE) on high-resistive n-type floating-zone (FZ) Si(1 1 1) (ρ>1000 Ω cm). They showed n-type conduction with a reduced electron concentration of an order of 1016 cm−3 at room temperature (RT). In contrast, β-FeSi2 films prepared without atomic hydrogen or prepared with molecular hydrogen showed p-type conduction with a large hole density of over 1018 cm−3. These results show that the atomic-hydrogen irradiation is an effective means to reduce the residual carrier concentration in undoped β-FeSi2 films

Effects of edges in spin-1/2 bond-alternating Heisenberg chains: Matrix-product variational approach

We make a matrix-product variational approach to spin-1/2 ferromagnetic-antiferromagnetic bond-alternating chains with anisotropy on their ferromagnetic bonds, especially under the open boundary condition. The rich phase diagram containing the Haldane, large-D, and two types of Neel phases is well reproduced with only two variational parameters. The on-bond anisotropy has a significant effect on the ferromagnetic coupling between neighboring spins and induces novel edge states peculiar to spin-1/2 chains.Comment: Phys. Lett. A 334, No. 2-3, 220 (2004

Ground-state properties of a Peierls-Hubbard triangular prism

Motivated by recent chemical attempts at assembling halogen-bridged transition-metal complexes within a nanotube, we model and characterize a platinum-halide triangular prism in terms of a Peierls-Hubbard Hamiltonian. Based on a group-theoretical argument, we reveal a variety of valence arrangements, including heterogeneous or partially metallic charge-density-wave states. Quantum and thermal phase competitions are numerically demonstrated with particular emphasis on novel insulator-to-metal and insulator-to-insulator transitions under doping, the former of which is of the first order, while the latter of which is of the second order.Comment: 9 pages, 7 figures. to be published in J. Phys. Soc. Jpn. Vol. 79, No.

Research on Smart Multi-story Car Parking Support System

金沢大学博士(工学）博士論文　要旨Abstract/本文Fulldoctoral thesi

Lessons Learned From Operations Planning and Preparation for EQUULEUS Launched Toward the Moon by SLS Artemis-1

EQUULEUS (EQUilibriUm Lunar-Earth point 6U Spacecraft) will be the world\u27s smallest spacecraft to explore around the Earth–Moon Lagrange point, which was launched on November 16, 2022, by NASA\u27s SLS (Space Launch System) Artemis-1. The primary mission of spacecraft is a trajectory control experiment, and its objective is to develop and demonstrate trajectory control techniques within the Sun-Earth-Moon region by flying to a libration orbit around the Earth-Moon Lagrange point L2 (EML2) along a low-energy transfer. EQUULEUS must perform a maneuver before the lunar flyby to stay within the Sun-Earth-Moon region. To perform DV1, we need to calculate and optimize the trajectory from launch to EML2. In addition, it is necessary to optimize the operation plan until the first lunar flyby, which is less than a week after launch. The reason for this is that the EQUULEUS trajectory will be significantly changed by the first lunar flyby, so appropriate trajectory control must be performed by that time. This paper presents the lessons learned in the operational preparation of EQUULEUS and those that should be applied to future missions to explore deep space, including the Moon and planets, by small and micro-satellites

Initial Operation Results of a 50kg-class Deep Space Exploration Micro-Spacecraft PROCYON

This paper presents the development and initial operation results of 50kg-class deep space exploration microspacecraft PROCYON (Proximate Object Close flYby with Optical Navigation), which was jointly developed by the University of Tokyo and Japan Aerospace Exploration Agency (JAXA). The primary mission of PROCYON is the world’s first demonstration of 50kg-class deep space exploration bus system which includes the demonstration of high-efficiency GaN-based SSPA (Solid State Power Amplifier) for communication and high-precision navigation by a novel method of DDOR (Delta Differential One-way Range) observation. PROCYON also has some secondary advanced missions, which are deep space flight to a Near-earth asteroid and high resolution observation of the asteroid during close and fast flyby, and the wide view scientific observation of geocorona by a Lyman alpha imager from a vantage point outside of the Earth’s geocoronal distribution. PROCYON was developed at very low cost (a few million dollars) and within very short period (about 1 year), taking advantage of the heritage from Japanese Earth-orbiting micro satellite missions. PROCYON was launched into an Earth departure trajectory together with Japanese second asteroid sample return spacecraft Hayabusa-2 on December 3, 2014, and it has achieved its primary mission and some of the secondary missions