The sparse atmosphere on the surface of Mars provides the necessary flight conditions for Mars unmanned aerial vehicles (UAVs) to perform low-altitude flights. This work presents a comprehensive overview of key technologies in the development of Mars UAVs, with a specific focus on rotary-wing Mars UAVs. It summarizes prototypes of rotary-wing Mars UAVs developed by various global research institutions. It reviews essential technologies in rotary-wing Mars UAV research, including the Mars near-surface atmospheric environment, aerodynamic characteristics, and principles of low-pressure flight control. This work also summarizes various experimental setups and ground test results for rotary-wing Mars UAVs. Furthermore, it discusses the future development trends of rotary-wing Mars UAVs.

The edge effect refers to what occurs when an object undergoes elastic contact with the edge of a material. This is common in practical applications, but the understanding of this phenomenon is not yet mature enough, and understanding the microscopic characteristics of the material regarding this phenomenon is necessary. This article investigates the edge effects of single-crystal silicon at different indentation positions through molecular dynamics simulations. The results indicate that the edge effect of the indentation is influenced by the indentation position and depth. The closer the indentation head is to the edge of the workpiece, the more particles are extruded from the side of the workpiece and the wider the collapse range of the indentation surface. At the same time, the indentation position also affects the distribution of the von Mises stress and phase transition area. When the edge effect occurs, the von Mises stress and phase transition region tend to be concentrated near the workpiece edge. This study demonstrates the atomic-scale deformation mechanism of single-crystal silicon under varying indentation positions.

This study investigates the material removal mechanism and the evolution of subsurface damage (SSD) in single-crystal silicon during ultra-precision machining using molecular dynamics (MD) simulations. A three-dimensional MD model was established by employing Tersoff and Morse interaction potentials to evaluate the effects of different cutting strategies on cutting response, stress distribution, surface morphology, and defect evolution. The results show that the multi-pass cutting strategy effectively reduces the mean cutting force and suppresses severe stress concentration regions exceeding 7 GPa. This improvement is mainly attributed to the progressive release of residual stress and the more gradual removal of material during successive cutting passes. The formation of SSD is dominated by lattice distortion and amorphous phase transformation, both of which are closely associated with localized high von Mises stress beneath the machined surface. Further analyses of surface morphology and defect density indicate that a multi-pass strategy with a single-pass cutting depth below 1 nm provides a favorable balance between machining efficiency and surface integrity. These findings provide atomistic insights into damage suppression and process optimization for the ultra-precision machining of brittle semiconductor materials.