Details of a Researcher - HIRAYAMA Hiroshi

Presentations -

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Motion Analysis of Capturing Space Debris using Tether

Hiroshi Hirayama, Keigo Sato

第32回宇宙技術および科学の国際シンポジウム (福井市) 2019.06 - 2019.06 日本航空宇宙学会

This paper describes motion analysis of a tethered satellite which contacts to a space debris in order to capture and remove it. One of difficulties about removal of the debris is how to capture an uncooperative object. We propose a capturing method using a tether. First, a mother satellite extends a tether with a daughter satellite, after a while they will be vertically stabilized by gravity gradient torque. Next, the satellites approaches to a target object in slow relative velocity. If the tether intercept the object in appropriate condition, the tether will wind around the target while the daughter will turn around it. The daughter is assumed to have some mechanisms to catch their own tether. Two dimensional motions of the mother, daughter and target are numerically simulated in this study. Some successful motions of the daughter turning around the target are shown when the parameters are appropriate. This method of capturing is very adaptable to electro-dynamic tether (EDT), which is a promising candidate to decelerate the space debris without propellant. So, this study will contribute to the removal of the space debris.

A Study on Movement of a Multipoint Suspended Explorer in a Lunar Hole

Takehiro Suzuki, Hiroshi Hirayama

第32回宇宙技術および科学の国際シンポジウム (福井市) 2019.06 - 2019.06 日本航空宇宙学会

This paper proposes a new method to descend into lunar hole for an unmanned explorer. The vertical holes of about 50 m diameter were found on the lunar surface in 2009. A candidate method to explore is tether suspended descent, but single tethered probe is limited only along vertical movement. So, we propose a lunar hole explorer that has a descending probe suspended by tethers from two or three points on a rim of the hole. The probe can move in two or three dimensionally by controlling length of each tether so that has advantage for geological survey on wall in the hole at close range. However it has limitation on movable region. First, the movable region was formulated from equilibrium of forces. Next the region is calculated and visualized assuming values of design parameters. Finally descending trajectories are proposed within the region.

A Study on Deformation of Tape Tether with Rarefied Atmospheric Drag

Morie Koseki, Hiroshi Hirayama

第32回宇宙技術および科学の国際シンポジウム (福井市) 2019.06 - 2019.06 日本航空宇宙学会

This paper describes a study on deformation analysis of the tape tether. A tape shaped tether has advantages that it is easy to extend and it has better survivability, compared to conventional string shaped tether. We focus on the tape tether in this study, because there are a lot of studies on behaviour or control of the string tether but not many analysis have been done on deformation of the tape tether.Hence, we study a deformation analysis of the tape tether considering rarefied atmospheric drag. Result of the numerical simulation shows the deformation of the tape tether and overall atmospheric drag.

Extension and Deformation Control Device of Morphable Beam

Shogo Saito, Hiroshi Hirayama

第32回宇宙技術および科学の国際シンポジウム (福井市) 2019.06 - 2019.06 日本航空宇宙学会

This paper describes mechanism of a Morphable Beam (MB) with a camera to observe surface of satellite. Increasing number of space debris is serious problem on sustainable space development. Especially, micro debris is believed to exist in huge number but its distribution is not clearly known, because it can be estimated only from inspection of damages on surface of objects retrieved from orbit. Thus, we propose the mechanism to solve these problems. First, we developed an extension and bending mechanism for the MB attached with an observation camera on the tip, which is controlled to reach target point. And then, we conducted three types of experiments to verify its performance of extension and deformation of the MB. Results of the experiments shows that the extension lengths and the deformations are almost proportional to control inputs. Therefore, it is considered that the proposed mechanism is capable to control the MB. According to the proposed mechanism, in-situ surface inspection of satellite becomes possible and the density data of micro debris can be acquired.

Feasibility Study on Capturing Space Debris using Metal Welding

Takeru Yoshimura, Hiroshi Hirayama

JSASS Northern Branch 2019 Annual Meeting and the 20th Symposium on Propulsion System for Reusable Launch Vehicles (Kakuda) 2019.03 - 2019.03 Japan Society for Aeronautical and Space Sciences

Proposal of a Soil Core Sampler for Asteroid

Ichiri Nakamura, Hiroshi Hirayama

JSASS Northern Branch 2019 Annual Meeting and the 20th Symposium on Propulsion System for Reusable Launch Vehicles (Kakuda) 2019.03 - 2019.03 Japan Society for Aeronautical and Space Sciences

A Study on Deformation of Tape Tether with Rarefied Atmospheric Drag

Morie Koseki, Hiroshi Hirayama

JSASS Northern Branch 2019 Annual Meeting and the 20th Symposium on Propulsion System for Reusable Launch Vehicles (Kakuda) 2019.03 - 2019.03 Japan Society for Aeronautical and Space Sciences

Proposal for Shapes of Wheels Driven on Icy Mars Polar Cap

Tsubasa Oyama, Hiroshi Hirayama

JSASS Northern Branch 2019 Annual Meeting and the 20th Symposium on Propulsion System for Reusable Launch Vehicles (Kakuda) 2019.03 - 2019.03 Japan Society for Aeronautical and Space Sciences

Development of a Deployable Small End Effector for Capturing Space Debris

Hiroshi Hirayama, Yuki Ohtani