Electrostatic dust shield system used for Lunar and Mars exploration equipment

Abstract

A unique shield system has been developed utilizing electrostatic force to remove dust breaking into bearings and mechanical seals of equipment used for space exploration. Because the performance of the former system was not satisfactory for mitigating dust intrusion, we added wire electrodes above the former system to improve the performance. As the result, approximately 95 % of dust was repelled from the gap. Moreover, we developed a numerical calculation algorithm using distinct element method for decreasing calculation load without decreasing calculation accuracy. It was predicted by the developed numerical method that the shield performance of the electrostatic dust shield system would be great on the Moon and Mars environment if dust would be charged strongly. This technology is expected to increase the reliability of equipment used in long-term manned and unmanned activities on the Lunar and Martian surface. 緒 言宇宙探査は人類の普遍的な夢であり，各国で様々なプロジェクトが進められている．わが国でも，月探査機 SELENE (Kato, et al., 2010) や小惑星探査機 Hayabusa の成功は記憶に新しい (久保田, 2010)．将来的にも各国で月 面開発や火星探査等が計画されているが，月や惑星表面の砂塵が機器・人体へ悪影響を及ぼすことが危惧されて いる． 実際にアポロ計画で月面上に存在するルナレゴリスが探査活動の大きな障害になったことや (Christofersen, et al., 2009, Gaier, 2005 Received 21 April 2014Adachi and Kawamoto, Transactions of the JSME (in Japanese), Vol.81, No.821 (2015) © 2015 The Japan Society of Mechanical Engineers [DOI: 10.1299/transjsme.14-00224] このような静電力を活用した技術は，可動部がなく構造が単純なために機械的な故障が生じづらく，制御が容 易，低消費電力，流体が不要という利点を持つことから近年注目されており , Calle, et al., 2011a, Kawamoto and Hasegawa, 2004, Kawamoto and Hara, 2011 2Adachi and Kawamoto, Transactions of the JSME (in Japanese), Vol.81, No.821 (2015) © Davies, 1945Davies, , 宗像, 1990Davies, , 静電気学会, 1998Davies, , 粉体工学会, 2005 Adachi and Kawamoto, Transactions of the JSME (in Japanese), Vol.81, No.821 (2015) © 2015 The Japan Society of Mechanical Engineers [DOI: 10.1299/transjsme.14-00224] Adachi and Kawamoto, Transactions of the JSME (in Japanese), Vol.81, No.821 (2015) © 2015 Adachi and Kawamoto, Transactions of the JSME (in Japanese), Vol.81, No.821 (2015) © 2015 10Adachi and Kawamoto, Transactions of the JSME (in Japanese), Vol.81, No.821 (2015) © 2015 Mio, H. and Shimosaka, A., Optimum cell size for contact detection in the algorithm of the discrete element method, Journal of Chemical Engineering of Japan, Vol. 38, No.12 (2005), pp.969-975.Mio, H., Kawamura, J., Higuchi, R., Shimosaka, A., Shirakawa, Y. and Hidaka, J., Effect of toner charge on developing behavior in two-component electrophotographic system by discrete element method,