Laser micro-thrust technology is a type of propulsion that uses a laser beam to ablate a propellant such as a metal or plastic. The ablated material is expelled out the back of the spacecraft, generating thrust. The technology has the advantages of high control precision, high thrust–power ratios, and excellent performances, and it has played an important role in the field of micro-propulsion. In this study, a solid propellant laser micro-thruster was developed and then applied for the attitude control of satellites during on-orbit tests. The micro-thruster had a volume of 0.5 U, a weight of 440 g, and a thrust range of 10 μN–0.6 mN. The propellant, 87% glycidyl azide polymer (GAP) + 10% ammonium perchlorate (AP) + 3% carbon nano-powder, was supplied via a double-layer belt, and the average power was less than 10 W. We present the development of the laser micro-thruster, as well as the results regarding the thruster propulsion performance. The thruster was launched into orbit on 27 February 2022 with the Chuangxin Leishen Satellite developed by Spacety. The on-orbit test of the thruster for satellite attitude control was carried out. The thruster was successfully fired in space and played an obvious role in the attitude control of the satellite. The experimental results show that the thrust is about 315 μN.

Laser ablation has been extensively studied by researchers due to its high precision, high efficiency processing capabilities, and wide range of application potentials. However, in a vacuum environment, due to the complexity of experimental conditions, specific application scenarios, and interdisciplinary interferences, more in-depth research on the ablation behavior of high-intensity lasers in vacuum is still insufficient. In response to such issues, experiments were conducted on titanium alloy perforation using a nanosecond laser in a vacuum environment. The variations in ablation depth and volume as functions of pulse energy, pulse number, and defocus were investigated. Both the depth and volume ablation efficiencies were calculated, and the three-dimensional morphology of the ablation holes was captured. Additionally, the ablation plume was observed to support the research conclusions. The results indicate that within the number of high-intensity laser pulses, the ablation depth per pulse can be increased by more than four times, and the average ablation volume per pulse can reach 0.97 µm³/µJ. The enhanced sputtering of molten material during the multi-pulse laser ablation process in a vacuum environment is identified as the primary factor contributing to the increased ablation efficiency. With the advancement of science and technology and the growing demand for applications, this research is crucial for the further development of fields such as space exploration and technology, advanced manufacturing technology, and basic scientific research.

In the field of laser ablation micro-propulsion, the property of double-layer tape has significant impact on the propulsion performance. In this paper, low temperature plasma was used to treat the surface of polyethylene terephthalate (PET) to improve its adhesion with energetic polymer. The PET surface pre- and post-plasma treatment was characterized by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), and the enhancement mechanism of the interface adhesion was discussed. In addition, the ablation performance of the double-layer tape after the plasma treatment was studied. The results showed that the plasma etching effect increased the root mean square roughness of the PET surface from 1.74 nm to 19.10 nm. In addition, after the plasma treatment, the number of C–OH/COOH bonds and O=C–O bonds increased, which also greatly improved the adhesion between the PET and energetic polymers. In the optimization of the ablation performance, the optimal laser pulse width was about 200 μs. The optimal values of the specific impulse (I_sp), impulse coupling coefficient (C_m), and ablation efficiency (η) were 390.65 s, 250.82 μN/W, and 48.01%, respectively. The optimization of the adhesion of the double-layer tape and the ablation performance lay the foundation for the engineering application of laser ablation micro-thrusters.

Plasma ignition technology is the research frontier in the field of energy and power. In this paper, a novel type of plasma jet igniter called pre-combustion plasma jet igniter is designed and the experimental results show that it has great potential in strengthening jet stiffness, improving ignition energy, decreasing ignition energy consumption and reducing igniter ablation. The value S called jet stiffness is defined for the first time to reflect the stiffness characteristics of the plasma jet. And the effects of jet gas flow rate, fuel-air ratio and input current on the jet stiffness are investigated experimentally. The experimental results show that the stiffness of the pre-combustion plasma jet is significantly stronger than that of the air plasma jet. When the total jet gas flow rate is increased from 16 L/min to 40 L/min, the stiffness of the air plasma jet and the pre-combustion plasma jet are increased by 73.3 % and 27.2 % respectively. When the current value reaches 30 A, the jet stiffness is increased by about 70 % compared to the input current of 20 A.

For improving the mechanical properties of Al-Ga-In-Sn alloys used to make dissolvable hydraulic fracturing tools, the effects of Cu and heat treatment on the microstructures and the Al-water reactivities of Alloys with Cu addition were investigated. The XRD and SEM were employed to investigate their microstructures. When the Cu content of alloys is above 1 wt%, Cu can dissolve in Al grains and form CuAl₂ phases at Al grain boundaries, which can strengthen Al-Cu-Ga-In-Sn alloys. Cu will not form intermetallic compounds with Ga, In, and Sn, so liquid GIS phases are still observed at Al grain boundaries. The Cu and Ga atoms can diffuse from CuAl₂ and GIS phases to Al grains during solution treatment. The CuAl₂ phases can precipitate in Al grains during the artificial aging treatment of alloys. The increment of Cu, and Ga contents of Al grains, and the formed CuAl₂ precipitates in Al grains will further strengthen the heat treatment alloys. Al-water reactivities of as-cast and heat treatment alloys were performed in different water temperatures. The solute Cu in Al grains and CuAl₂ phases at Al grain boundaries will occupy the contacting sites for Al reacting with water, leading to H₂ generation rates and H₂ yield of reactivity of Cu-bearing alloys with water decreasing. After heat treatment, the increment of Cu content and CuAl₂ precipitates in Al grains will occupy more contacting sites for Al reacting with water, resulting in a lower H₂ yield of Al-water reaction of heat treatment alloys than that of as-cast alloys.