Graphene-Based Laser Propulsion for Space Application

Abstract

Graphene-based laser propulsion presents a promising advancement for space applications by offering a propellant-free propulsion system that could significantly enhance the efficiency and capability of space missions. This thesis investigates the utilization of graphene aerogels for laser propulsion, focusing on the characterization of graphene inks and aerogels and the evaluating the effect of several parameters on the propulsion efficiency.

Graphene exhibits remarkable properties such as high electrical conductivity, mechanical strength, and thermal stability, making it an ideal candidate for laser propulsion systems. The research involved the synthesis of graphene aerogels through a meticulous process of preparing graphene inks using ultrasonic exfoliation of graphite intercalated compound. The inks were optimized for different concentrations, surfactants, and binders through an iterative process. The graphene aerogels were characterized using techniques like Scanning Electron Microscopy (SEM) and Raman spectroscopy to understand their structural and compositional properties. Mechanical tests were also done to test the stability of the aerogels.

State-of-the-art experimental setups were designed to test the laser propulsion of graphene aerogels under different conditions inside a thermal vacuum chamber (TVAC), which simulates the space environment in terms of vacuum levels and temperatures. Various configurations, including a quartz tube setup, a pendulum setup, and a graphene sheet setup, were utilized to measure the propulsion force generated by laser irradiation. The results demonstrated that graphene aerogels could be effectively propelled by laser beams, with the propulsion efficiency being influenced by factors such as vacuum level, concentration of inks, densities of aerogels, laser powers, and freezing techniques, which affect the microstructure. Propulsion efficiency is evaluated based on average, maximum, and specific thrust.

The findings demonstrated that higher vacuum levels significantly enhanced propulsion efficiency, leading to the use of the highest achievable vacuum for all subsequent tests. Increased concentrations of inks and aerogels correlated with greater propulsion force, and higher laser power further increased propulsion efficiency. Pure graphene aerogels exhibited substantially greater propulsion than graphene oxide aerogels, emphasizing the importance of material composition. For aerogels made from lower ink concentrations, the liquid nitrogen (LN) freezing technique was more effective, whereas, for the ones made of higher concentrations, the conventional freezer method performed better. Scanning Electron Microscopy (SEM) characterizations supported these results, showing that freezing techniques influence interlayer spacing in graphene aerogels, thereby affecting propulsion efficiency.

Date of Award	20 Jul 2024
Original language	American English
Supervisor	Sean Swei (Supervisor)