When a spacecraft is available in for a touchdown (or a tag much like what OSIRIS-REx did), there’s a turbulent jet that factors straight right into a mattress of particles. How these particles react — how they erode and the crater that varieties — depends upon many components, together with the cohesion between particles. In these experiments, researchers investigated such a jet (in air) and its influence on particles with differing quantities of cohesion.
When there’s little cohesion between particles, erosion takes place a single particle at a time (Picture 1). As soon as there’s some cohesion, the jet’s velocity must be greater to set off erosion (Picture 2). As soon as erosion does start, it contains each singular and clumped particles. In extremely cohesive beds, velocities should be even greater to create erosion, which takes place with massive clusters of particles flying off collectively (Picture 3). (Picture and analysis credit score: R. Sharma et al.)
