Study of ejecta properties during plume surface interactions using three-dimensional optical diagnostic technique *

Plume surface interaction (PSI), which is the interaction between the rocket plume and planetary surface, leads to crater formation and dust plumes at the landing site and was one of the major problems faced during the Apollo program. With the Artemis program, NASA is aiming to return humans back to the moon, and a comprehensive understanding of the PSI process is vital for ensuring the safety of future missions. While the crater formation process during PSI has been studied over the years, accurate data on the behavior of the particle ejecta from PSI process is scarce, particularly from unobstructed full-domain experiments. In this study, we apply three-dimensional optical diagnostic techniques to study the simultaneous temporal velocity and trajectory of the particle ejecta and crater evolution in a full-domain, atmospheric, bench-scale facility. Preliminary results show that the particles were ejected more vertically with reduced velocity over time while the crater radius growth stagnated, and the crater depth continued increasing. Further investigation and analysis of these phenomena along with the contributing mechanisms will be presented.