A Zero-Gravity Instrument to Study Low Velocity Collisions of Fragile Particles at Low Temperatures

TL;DR

This paper presents a specialized vacuum instrument designed for zero-gravity experiments on fragile particles, enabling detailed collision studies relevant to planetary formation at low temperatures and velocities.

Contribution

The paper introduces a versatile, high-resolution collision experiment setup capable of operating in reduced gravity and cryogenic conditions, with successful deployment during multiple parabolic flights.

Findings

Over 300 collisions recorded at velocities 0.03-0.28 m/s

Operated for 2.4 hours in reduced gravity conditions

Captured high-speed images at 107 fps from two angles

Abstract

We discuss the design, operation, and performance of a vacuum setup constructed for use in zero (or reduced) gravity conditions to initiate collisions of fragile millimeter-sized particles at low velocity and temperature. Such particles are typically found in many astronomical settings and in regions of planet formation. The instrument has participated in four parabolic flight campaigns to date, operating for a total of 2.4 hours in reduced gravity conditions and successfully recording over 300 separate collisions of loosely packed dust aggregates and ice samples. The imparted particle velocities achieved range from 0.03-0.28 m s^-1 and a high-speed, high-resolution camera captures the events at 107 frames per second from two viewing angles separated by either 48.8 or 60.0 degrees. The particles can be stored inside the experiment vacuum chamber at temperatures of 80-300 K for several uninterrupted hours using a built-in thermal accumulation system. The copper structure allows cooling down to cryogenic temperatures before commencement of the experiments. Throughout the parabolic flight campaigns, add-ons and modifications have been made, illustrating the instrument flexibility in the study of small particle collisions.