Helical Propulsion: A Novel Model for High-Speed Interstellar Travel Based on Medium Dynamics and a Corresponding Spacecraft Design Framework

This paper proposes and rigorously argues for a novel dynamic model for interstellar travel. The core conclusion is that in a cosmic space containing a uniform medium, when an object's velocity exceeds a critical value a helical trajectory surpasses conventional linear propulsion in both energy efficiency and dynamic stability. We establish a generalized helical dynamics equation containing a Coriolis-medium coupling term, revealing that the periodic conversion between kinetic and rotational energy is the intrinsic mechanism maintaining high-speed stability. Based on this model, we parametrically design a Spherical Helical Propulsion Vehicle (SSPV). Through coordinated control between a main thruster and a distributed array of auxiliary thrusters, the SSPV can actively induce helical motion when and enter a low-energy, self-sustaining helical cruise state when. Numerical simulations indicate that in an effective medium with ρ _eff ≥ 10 ²⁷ kg/m ³ , the SSPV's average linear velocity for the same energy input can reach 2.3 times that of traditional linear propulsion. Finally, the paper proposes a cost-effective, three-stage validation plan involving ground and in-orbit experiments, with an initial phase budget under $3 million. This work provides a novel paradigm with a rigorous mathematical foundation and an engineering implementation path to break the current propulsion speed barrier.