A novel facility for reduced-gravity testing: a set-up for studying low-velocity collisions into granular surfaces

摘要

This work presents an experimental design for studying low-velocitycollisions into granular surfaces in low-gravity. In the experiment apparatus,reduced-gravity is simulated by releasing a free-falling projectile into asurface container with a downward acceleration less than that of Earth'sgravity. The acceleration of the surface is controlled through the use of anAtwood machine, or a system of pulleys and counterweights. The starting heightof the surface container and the initial separation distance between theprojectile and surface are variable and chosen to accommodate collisionvelocities up to 20 cm/s and effective accelerations of ~0.1 - 1.0 m/s^2.Accelerometers, placed on the surface container and inside the projectile,provide acceleration data, while high-speed cameras capture the collision andact as secondary data sources. The experiment is built into an existing 5.5 mdrop-tower frame and requires the custom design of all components, includingthe projectile, surface sample container, release mechanism and decelerationsystem. Data from calibration tests verify the efficiency of the experiment'sdeceleration system and provide a quantitative understanding of the performanceof the Atwood system.