Experimental study of sliding forces of lander footpad in simulant lunar soil

The study of the interaction between lunar lander footpad and lunar soil during the moon landing has great importance owing to the strong impact which affects safe landing and normal performance of inner precise instruments. Since horizontal slide is the complicated landing process, model tests on the process of dragging footpad in simulant lunar soil are carried out with the self-developed test device to investigate the changes of horizontal and vertical forces on footpad. The influences of relative densities, sliding velocities, penetrations and turn angles on these forces are further studied. The results show that the horizontal forces appear almost linear increase with the increase of vertical forces. Besides, the forces increase with the growth of relative density of soil, horizontal velocity and penetration. The forces are greatly influenced by the turn angle. When turn angle of footpad is (8 degrees, 26 degrees), the force of lander footpad is the least. When the turn angle is (0 degrees, -26 degrees), which means bulldozing process, the force is the largest. This turn angle (0 degrees, -26 degrees) is appropriate for the buffer structure of lander to dissipate impact energy in slip process.