Ryu Funase
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Global and Sequential Imaging Observation of the Earth's Plasmasphere by PHOENIX Onboard EQUULEUS Open
The Plasmaspheric Helium ion Observation by Enhanced New Imager in eXtreme ultraviolet (PHOENIX) onboard EQUilibriUm Lunar‐Earth point 6U Spacecraft (EQUULEUS) performed global imaging observations of the Earth's plasmasphere from a meridi…
Finding the optimal flyby distance for the Comet Interceptor comet mission Open
The Comet Interceptor mission will attempt to fly by a yet undetermined target comet. The conditions of this flyby will remain largely unknown up to the selection of target and possibly even the moment of encounter. A detailed trajectory d…
View article: Design Verification of Whipple Bumper Shields for Protecting Small Spacecraft from Hypervelocity Impacts During Fast Fly-Bys to Dusty Objects
Design Verification of Whipple Bumper Shields for Protecting Small Spacecraft from Hypervelocity Impacts During Fast Fly-Bys to Dusty Objects Open
JAXA provides a 24U-class daughtership “B1” to ESA’s Comet Interceptor (CI) mission for fast flyby observation of a long-period comet or an interstellar object. The spacecraft must survive in the dusty environment with a lightweight impact…
GEOspace X-ray imager (GEO-X) Open
GEOspace X-ray imager (GEO-X) is a small satellite mission aiming at visualization of the Earth’s magnetosphere by X-rays and revealing dynamic couplings between solar wind and the magnetosphere. In-situ spacecraft have revealed various ph…
Power Management of Lunar CubeSat Mission EQUULEUS Under Uncertainties of Power Generation and Consumption Open
This paper highlights the power system design of the equilibrium lunar–Earth point 6-unit spacecraft (EQUULEUS), which will fly to the second Earth–Moon Lagrange point and perform a variety of scientific and technological missions. The lim…
System requirements analysis for JAXA's contribution to Comet Interceptor mission: autonomous navigation, guidance and attitude control for a hyperbolic comet fly-by Open
Comet Interceptor, to be launched in 2028, is a recently-selected ESA/JAXA mission aimed to perform the first fly-by of a pristine long-period comet. As part of the mission’s Phases A/B (feasibility analysis and preliminary design), this w…
Tube Stochastic Optimal Control for Nonlinear Constrained Trajectory Optimization Problems Open
Recent low-thrust space missions have highlighted the importance of designing trajectories that are robust against uncertainties. In its complete form, this process is formulated as a nonlinear constrained stochastic optimal control proble…
View article: Mission to Earth–Moon Lagrange Point by a 6U CubeSat: EQUULEUS
Mission to Earth–Moon Lagrange Point by a 6U CubeSat: EQUULEUS Open
EQUULEUS (EQUilibriUm Lunar-Earth point 6U Spacecraft) will be the world's smallest spacecraft to explore the Earth-Moon Lagrange point. It is being jointly developed by JAXA (Japan Aerospace Exploration Agency) and the University of Tokyo…
Development of On-board Image Processing Algorithm to Detect Lunar Impact Flashes for DELPHINUS Open
DELPHINUS is a camera system mounted on EQUULEUS, which is planned to be launched using NASA’s Space Launch System EM-1 in 2021. DELPHINUS aims to investigate size distribution, influx ratio, and daily variation of meteoroids in the cislun…
A Study on Debris Removal System Using Laser Pressure from Ground Stations Open
The amount of debris in space is increasing every year, and its effect on satellite missions is worsening. In this research, a method for removing debris using laser radiation pressure from a ground station is proposed. This method does no…
Flight Model Development and Ground Demonstration of Water Resistojet Propulsion System for CubeSats Open
The University of Tokyo has proposed a water resistojet thruster with a high certainty of liquid–vapor separation and low power consumption. In this propulsion system, liquid water is periodically vaporized in a pulsating manner to generat…
Space-based Observation of Lunar Impact Flashes Open
When a meteoroid impacts the Moon at several tens of km/s, a brilliant flash, referred to as a lunar impact flash, can be observed at the point of impact by ground-based telescope. Lunar impact flashes observed from the ground are biased d…
On-Orbit Operation Results of the World's First CubeSat XI-IV – Lessons Learned from Its Successful 15-years Space Flight Open
In recent years, the size and cost of satellites have been reduced, and the frequent launch of satellites have been realized even by small private companies and universities. The first step of this big wave was the first successful launch …
Estimation Algorithm of Relative Position and Attitude during Proximity Rendezvous Using Multiple Ultra-Wide-Band Devices Open
This research proposes estimation algorithms of relative position and attitude during interplanetary proximity rendezvous and docking by using ultra-wide-band (UWB) devices—which are small, low-power devices to be used for communication be…
Accurate Aerodynamic Model of Membranes in Free-Molecular Flow for Deorbit Device Design Open
This paper proposes an accurate aerodynamic model for membrane structures in free-molecular flow that allows the calculation of torque and force exerted on them, and which can be used for precise analysis of the attitudes and orbital dynam…
Solar System Exploration Sciences by EQUULEUS on SLS EM-1 and Science Instruments Development Status Open
EQUULEUS is a spacecraft to explore the cislunar region including the Earth-Moon Lagrange point L2 (EML2) and will be launched by NASA’s SLS EM-1 rocket. Although the size of EQUULEUS is only 6U, the spacecraft carries three different scie…
Fundamental Ground Experiment of a Water Resistojet Propulsion System: AQUARIUS Installed on a 6U CubeSat: EQUULEUS Open
In this study, a water resistojet propulsion system, named AQUARIUS, is proposed and the breadboard model (BBM) test results and the engineering model (EM) design are described.AQUARIUS will be on-boarded the SLS EM-1 CubeSat: EQUULEUS, wh…
Flight Model Design and Development Status of the Earth - Moon Lagrange Point Exploration CubeSat EQUULEUS Onboard SLS EM-1 Open
EQUULEUS (EQUilibriUm Lunar-Earth point 6U Spacecraft) will be the world’s smallest spacecraft to explore the Earth―Moon Lagrange point. The spacecraft is being jointly developed by JAXA and the University of Tokyo and will be launched by …
Ecliptic North‐South Symmetry of Hydrogen Geocorona Open
The hydrogen exosphere constitutes the uppermost atmospheric layer of the Earth, and its shape may reflect the last stage of the atmospheric escape process. The distribution of hydrogen in the outer exosphere remains unobserved because out…
Constrained Optimal Flyby Guidance Algorithm by Iterative Two-Stage Stochastic Programming Open
Interplanetary micro-spacecraft have been recently demonstrated for various missions. Orbital control of micro-spacecraft is challenging because the spacecraft systems have severe constraints. This paper presents a constrained optimal flyb…
Attitude Determination and Control System for the PROCYON Micro-Spacecraft Open
This paper describes development strategies and on-orbit results of the attitude determination and control system (ADCS) for the world's first interplanetary micro-spacecraft, PROCYON, whose advanced mission objectives are optical navigati…
Development of the Water Resistojet Propulsion System for Deep Space Exploration by the CubeSat: EQUULEUS Open
In this study, Water micro-propulsion system AQUARIUS (AQUA ResIstojet propUlsion System) is proposed for 6U CubeSat: EQUULEUS to explore the deep space. AQUARIUS uses storable, safe and non-toxic propellant: water, which allows for downsi…
On-orbit Demonstration of Satellite Software Architecture With a Flexible Reconfiguration Capability Open
In recent years, as practical applications of microsatellites spread, missions of them have become advanced and it has been required that the development of them is short-term and low-cost. In order to achieve these requirements, two point…
Quasi-static panel deployment and retraction using electromagnetic force in satellite missions Open
This paper proposes a novel control technique for a new panel quasi-static deployment and retraction method using electromagnetic force. This panel system is modeled as a multibody dynamic system which will be used for numerical simulation…