Project STINGRAY This paper presents Project STINGRAY, a conceptual spacecraft propulsion system that uses the momentum of external proton flows as a working medium. The proposed spacecraft captures solar-wind protons using electrostatic and magnetic fields, concentrates them in a working channel, and redirects them in a controlled manner to generate thrust without onboard propellant consumption. The work includes the physical foundations of the concept, a mathematical model, mass and dimensional estimates, and a preliminary mission scenario to Jupiter. It also introduces the concept of plasma surfing between gas giants along natural magnetospheric plasma corridors and formulates a model of interplanetary plasma navigation in which space is treated as a structured energetic medium with distributed resources. Revision 2.1 - corrected and refined