Space tethers are subject to high collision risk due to the very large collision cross-sectional area and they can be cut easily by impacts of small particles because of the thin diameter. Therefore, double-line tethers have been proposed to extend their life. The previous works assessed the survivability of double-line tether treated two wires independently. This treatment assumed that the distance between two wires is infinite. Physically, the distance between two wires is finite, however. Therefore, two wires could be cut simultaneously if the particle cutting through the first wire has or the remnant melted or vaporized at impact on the first wire have still enough energy to cut the second wire. As a result, unfortunately, once we consider that two wires can be cut simultaneously by a single impact, the merit of double-line tether disappears. Double line tether without sufficient clearance between two lines would not survive longer than expected. In this paper we will describe how to treat double line tether with a finite clearance between two lines and provide some results from applying this technique to a micro tether satellite named QTEX, being developed at Kyushu University.