Optimum sizing of bare-tape tethers for de-orbiting satellites at end of mission

摘要

De-orbiting satellites at end of mission would prevent generation of new space debris. A proposed de-orbit technology involves a bare conductive tape-tether, which uses neither propellant nor power supply while generating power for on-board use during de-orbiting. The present work shows how to select tape dimensions for a generic mission so as to satisfy requirements of very small tether-to-satellite mass ratio m_t/M_S and probability N_f of tether cut by small debris, while keeping de-orbit time t_f short and product t_f × tether length low to reduce maneuvers in avoiding collisions with large debris. Design is here discussed for particular missions (initial orbit of 720 km altitude and 63° and 92° inclinations, and 3 disparate M_S values, 37.5, 375, and 3750 kg), proving it scalable. At mid-inclination and a mass-ratio of a few percent, de-orbit time takes about 2 weeks and N_f is a small fraction of 1%, with tape dimensions ranging from 1 to 6 cm, 10 to 54 μm, and 2.8 to 8.6 km. Performance drop from middle to high inclination proved moderate: if allowing for twice as large m_t/M_S, increases are reduced to a factor of 4 in t_f and a slight one in N_f, except for multi-ton satellites, somewhat more requiring because efficient orbital-motion-limited electron collection restricts tape-width values, resulting in tape length (slightly) increasing too.