The Japan Aerospace Exploration Agency (JAXA) is investigating an active space debris removal system that employs highly-efficient electrodynamic tether (EDT) technology. As an electron collector of the EDT for debris de-orbiting, a multiple bare tethers are to be used. In order to simulate the EDT operation, current-voltage (I-V) characteristics of the multiple bare tethers need to be investigated on conditions that a theoretical formula cannot be applied. Therefore, numerical simulations and ground experiments have been conducted to obtain the I-V characteristics. A result of the numerical simulations and the ground experiments showed a double-line bare tethers can collect larger current density than a single-line bare tether.
