A Mid-Earth Elliptical Orbiting Tether for Nuclear Waste Disposal

摘要

Tethers have been the subject of much analysis and speculative advanced missions; space elevators have captured the imagination of science fiction writers and space scientists for many years. There have been many successful and partially successful tether missions; most have been beset by minimal funding, consequently, they have operated without redundancy, operated as secondary payloads and the failures which have occurred have been due to, at times, relatively insignificant items in significant areas failing; items which could have enjoyed better quality or redundancy with adequate funding. The proposed innovative technology reduces the insertion velocity necessary to achieve low earth orbit (or low Mars or low Lunar orbit) by ~2.5 km/sec. This results in huge reductions in the rocket mass ratios necessary, which is reflected as doubling of the payload for existing rockets, or as reduced risk for Fully Reusable Earth to Orbit Systems (FRETOS) capable of enabling cheap access to space (< $200/kg), necessary for nuclear waste disposal. A hanging, momentum-exchange tether is proposed that rapidly contracts when it captures a payload to lift it above 90% of the Earth's debris field and re-circularizes above 99% of the debris field using advanced electric thrusters (Electrodeless Lorentz Force or ELF Thrusters), for example. This paper addresses the impact of a MEO tether in elliptical orbit designed for nuclear waste disposal. The E-MEO tether allows a realistic reduction of the orbital DV by 1.5-2.5 km/s. This reduction virtually enables SSTO of LOX-LH_2 and even LOX-Kerosene SSTO vehicles are within the range of feasibility. Analyses on tether stability were conducted, power requirements were analyzed, methods to meliorate certain longitudinal and transverse vibrational modes were proposed and analyzed. Methods to dramatically reduce the power required to winch up the tether were proposed and evaluated. We conclude that a MEO tether can be built with existing technologies and will result in major improvements in reliable access to space and at dramatically reduced cost, with an appropriately sized SSTO performing a nuclear waste disposal mission, it is feasible to reduce the to-orbit cost to below $150/kg.