Performance optimization of ammonium dinitramide-based liquid propellant in pulsed laser ablation micro-propulsion using LIBS

The efficacy of spacecraft propulsion systems significantly depends on the choice of propellant. This study utilized laser-induced breakdown spectroscopy (LIBS) to investigate the impact of different fuel types, fuel ratios, and laser energies on the plasma parameters of ammonium dinitramide (ADN)-based liquid propellants. Our findings suggest that 1-allyl-3-methylimidazolium dicyanamide (AMIMDCA) as a fuel choice led to higher plasma temperatures compared to methanol (CH₃OH) and hydroxyethyl hydrazine nitrate (HEHN) under the same experimental conditions. Optimization of the fuel ratio proved critical, and when the AMIMDCA ratio was 21wt.% the propellants could achieve the best propulsion performance. Increasing the incident laser energy not only enhanced the emission spectral intensity but also elevated the plasma temperature and electron density, thereby improving ablation efficiency. Notably, a combination of 100 mJ laser energy and 21wt.% AMIMDCA fuel produced a strong and stable plasma signal. This study contributes to our knowledge of pulsed laser micro-ablation in ADN-based liquid propellants, providing a useful optical diagnostic approach that can help refine the design and enhance the performance of spacecraft propulsion systems.