Design and experimental investigation of an optical fibre based ignition system for space propulsion systems

Abstract

This paper presents the development and evaluation of a fibre-based laser ignition system for space propulsion applications, focusing on its design, operational reliability and technological limitations. The design of key components such as the core laser system, optical fibers, multiplexer, and focusing optics is discussed. The effectiveness of the ignition system was demonstrated by successfully igniting a liquid oxygen/gaseous hydrogen thruster under in-space conditions. Tests were conducted to determine the minimum pulse energy required for ignition using step index fused silica fibers with core diameters 400 µm, 600 µm and 800 µm and different laser pulse focusing configurations. The results showed that ablationdriven ignition concepts required minimum pulse energies as low as 2.9 mJ, while the laser-plasma driven approach was unsuccessful in achieving ignition due to limitations in laser pulse intensity at the focal plane in the current setup.