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

TL;DR

This paper introduces an innovative experimental setup for studying low-velocity collisions into granular surfaces under simulated low-gravity conditions, combining controlled acceleration, high-speed imaging, and precise data collection.

Contribution

The work presents a custom-designed facility integrating an Atwood machine and high-speed cameras to simulate and analyze low-gravity collisions with granular surfaces.

Findings

Calibration tests confirm the deceleration system's effectiveness.

The setup accurately reproduces low-gravity collision velocities.

Data collection methods provide detailed insights into collision dynamics.

Abstract

This work presents an experimental design for studying low-velocity collisions into granular surfaces in low-gravity. In the experiment apparatus, reduced-gravity is simulated by releasing a free-falling projectile into a surface container with a downward acceleration less than that of Earth's gravity. The acceleration of the surface is controlled through the use of an Atwood machine, or a system of pulleys and counterweights. The starting height of the surface container and the initial separation distance between the projectile and surface are variable and chosen to accommodate collision velocities 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 and act as secondary data sources. The experiment is built into an existing 5.5 m drop-tower frame and requires the custom design of all components, including the projectile, surface sample container, release mechanism and deceleration system. Data from calibration tests verify the efficiency of the experiment's deceleration system and provide a quantitative understanding of the performance of the Atwood system.