著者

Yoshiki YAMAGIWA Koki TAO Shoji SATO Kiyotoshi OTSUKA Yoji ISHIKAWA

出版者

THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES

雑誌

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN (ISSN:18840485)

巻号頁・発行日

vol.16, no.2, pp.165-171, 2018 (Released:2018-03-04)

参考文献数

12

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The understanding of cable dynamics is one of the most important issues for the design and construction of a space elevator. We propose a new method for constructing the space elevator by simultaneously deploying cables upward and downward from the main space station maintained in GEO and balancing both cables. The analysis is performed using our originally developed cable dynamics model. The model is a two-dimensional lamped mass model. In the model, the tether is modelled by mass points, which are connected to each other by a spring and a damper, and are pulled out per assumed length. In this study, we first analyze the cable dynamics and stress for assumed deployment conditions of the cables. We then obtain the total impulse necessary to keep the main station in GEO and control the cable speed during deployment so that it does not exceed the maximum stress of the cable. The results are also compared with the preceding method for the same conditions. The initial result shows that with the proposed cable-deployment method, the total propellant mass necessary to control cable dynamics while maintaining the station in GEO can be decreased by about one-third compared with that necessary to raise the main station to higher orbit and to control cable dynamics as in the preceding cable-deployment method.

著者

Tomoya FUJIMOTO Hirotaka OTSU Ikkoh FUNAKI Yoshiki YAMAGIWA

出版者

THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES

雑誌

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES (ISSN:05493811)

巻号頁・発行日

vol.53, no.180, pp.84-90, 2010 (Released:2010-08-06)

参考文献数

14

被引用文献数

2

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To propel a spacecraft away from the Sun, a magneto plasma sail (MPS) spacecraft produces an artificial magnetic cavity to block the hypersonic solar wind. To make a large magnetic cavity sufficient to obtain significant thrust, the MPS spacecraft increases the magnetic cavity size using an onboard coil with assistance from a plasma jet. This process is called magnetic field inflation. In this study, we performed ideal and resistive magnetohydrodynamic (MHD) analyses to investigate the magnetic diffusion effect on the magnetic field inflation process. Our results indicate that a dipole-like magnetic field is drastically deformed by a plasma jet; when the magnetic Reynolds number Rm was 10 or more, the magnetic field lines were nearly identical to the streamlines of the plasma jet. Hence, no magnetic diffusion effect appeared for Rm>10. Meanwhile, when Rm is an order of unity, the magnetic diffusion effect was remarkable in the current sheet formed around equatorial region. For example, when the divergence angle of a plasma jet in the polar direction was 30°, the magnetic field strength at 40 m from the spacecraft (calculated by resistive MHD model) was 19% smaller than the ideal MHD model (Rm=∞).