Conceptual Design and Analysis of Rotating Skyhook Orbital Tether System (RSOTS)

Abstract

The Rotating Skyhook Orbital Tether System (RSOTS) is a proposed space-launch-assistance architecture in which a tethered station in low Earth orbit (LEO) rotates a high-tensile cable so that its lower tip periodically sweeps to approximately 280–320 km altitude. A payload launched by a conventional rocket or hypersonic carrier vehicle to this rendezvous altitude is captured by the rotating tip, carried through the tether's arc, and released at higher velocity into a target orbit. The net result is a reduction in the rocket delta-V requirement of 30–50%, translating directly into smaller, cheaper, and more frequently reusable launch vehicles. This paper presents a comprehensive technical analysis of the RSOTS concept: orbital mechanics derivations, tether load analysis, materials selection, system mass budgets, economic modelling, identified engineering challenges with proposed mitigations, expansion scenarios including interplanetary applications, and a structured five-phase development roadmap from simulation to commercial operations. The key enabling technology, carbon nanotube (CNT) composite tether material, is advancing rapidly; however, the baseline architecture using currently available Zylon (PBO) fibre is sufficient for demonstration missions and yields a deployable system mass of approximately 23,000 kg, compatible with a single Falcon Heavy launch.