Resonant space tethered system for lunar orbital energy harvesting

摘要

Using a space tether system attached to the Moon's surface can in principle lead to energy harvesting from the mechanical damping of the tether as it experiences elongational motion due to time-varying tidal forces. It is shown that such a tether system can in principle provide electricity generation for lunar infrastructure, although the power generated is modest relative to the scale of engineering required. First, the dynamics of the coupled planar elongation and librational motion is established for a massless, elastic and damped tether with a large tip-mass in the frame of the elliptic Earth-moon restricted three-body (EEMRTB) system. Equilibria at the natural L-2 point are obtained as reference positions to perform the analysis. The method of multiple scales is then used to obtain the steady state amplitude-frequency response by ordering key variables and parameters appropriately. The steady-state power output determined by the elasticity, length and damping of the tether is presented. Specific resonances for peaks of power output, together with corresponding resonance regions, are also investigated along with suggestions for tradeoffs among the key system parameters. Finally, the optimal damping for maximum power output is determined, together with the corresponding natural length and elasticity of the tether.