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To improve the cushioning performance of soft-landing systems, a novel origami-inspired combined cushion airbag is proposed. The geometry size, initial pressure, and exhaust vent area of the cushion airbags are designed preliminarily using a theoretical model. The finite element models, including the returnable spacecraft and cushion airbags, are established via the control volume method (CVM) to analyze the impact dynamic behavior and cushioning performance during the landing attenuation process. The cushioning performance of the cushion airbags in complex landing environments are studied to investigate the influence of horizontal velocity, lateral velocity and nonhorizontal landing surfaces. Four design parameters of the cushion airbags, including the initial pressure, venting threshold pressure, exhaust vent area and polygon edge number, are employed to study their influence on the cushioning performance. A multi-objective optimization model of the cushion airbags based on the neural network and multi-objective water cycle algorithm is established to realize the rapid optimization design. The Pareto front of the maximum overload and specific energy absorption is obtained. The analysis results show that the maximum overload of the proposed combined cushion airbags is 7.30 g. The system with the anti-rollover design can avoid rollover and achieve outstanding cushioning performance in complex landing environments. The maximum overload of the returning spacecraft is decreased by 16.4% from 7.30 g to 6.10 g after multi-objective optimizations. This study could provide the technical support for the soft-landing system design of returnable spacecrafts.

In the context of green aviation, as an internationally recognized solution, hydrogen energy is lauded as the “ultimate energy source of the 21st century”, with zero emissions at the source. Developed economies with aviation industries, such as Europe and the United States, have announced hydrogen energy aviation development plans successively. The study and development of high-energy hydrogen fuel cells and hydrogen energy power systems have become some of the future aviation research focal points. As a crucial component of hydrogen energy storage and delivery, the design and development of a safe, lightweight, and efficient hydrogen storage structure have drawn increasing consideration. Using a hydrogen-powered Unmanned Aerial Vehicle (UAV) as the subject of this article, the crash characteristics of the UAV’s hydrogen storage structure are investigated in detail. The main research findings are summarized as follows: (1) A series of crash characteristics analyses of the hydrogen storage structure of a hydrogen-powered UAV were conducted, and the Finite Element Analysis (FEA) response of the structure under different impact angles, internal pressures, and impact speeds was obtained and analyzed. (2) When the deformation of the hydrogen storage structure exceeds 50 mm, and the strain exceeds 0.8, an initial crack will appear at this part of the hydrogen storage structure. The emergency release valve should respond immediately to release the gas inside the tank to avoid further damage. (3) Impact angle and initial internal pressure are the main factors affecting the formation of initial cracks.

For the rigid impact and flexible impact in space operation tasks, impact dynamic models between two objects are established in this paper, laying the model foundation for controlling or suppressing the impact. For the capture task between a grapple shaft and a rigid body, the impact dynamic model is established based on the Zhiying–Qishao model. Moreover, by introducing a friction factor into the original impact model, an improved dynamic model between two rigid bodies is proposed. For the capture task with flexible impact, an impact dynamic model between the grapple shaft and a flexible wire rope is established based on the dynamic model of the flexible wire rope. The ground experiments and simulations are carried out with two objects on an air flow table. The experiment results validate the impact dynamic model proposed in this paper.