Description: Vertical landing of a rocket vehicle on an irregular, unimproved surface has a number of challenges, including generation of a dust cloud that creates an observable event, erosion of the surface leading to a crater, rocket instability, damage to the vehicle, and optical occlusion. The proposed research program will focus on the development and demonstration of a high-speed (10-100 kHz) fiber-based imaging solution that can be used for evaluating PSI interactions at multiple resolutions (5–500 µm), with tomographic information of the plume envelope. This work will enable state-of-the-art measurements of particle sizes, distributions, and velocities for the PSI program for scaled tests at NASA facilities under near vacuum conditions. The new capability to quantify ejecta dynamics will fill the gaps in the current understanding of PSI for future landers, including the Moon and Mars. By selectively detecting various regions with varying resolution and angles, it will be possible to minimize interferences, optimize dynamic range, and obtain 2D–3D flowfield information throughout key regions of the landing area rocket plume. The proposed work will result in a robust instrument that can provide key information needed to validate numerical models and predict the potential challenges associated with unimproved landing sites.

Benefits: The proposed work will pave the way for development of a full prototype instrument for testing under a range of plume surface interaction conditions at NASA facilities during the Phase II period and beyond. The prototype instrument will fill a critical gap in measurements of particle sizes, velocities, and flow structures impacting the safety and reliable operation of NASA launch and landing vehicles for terrestrial and planetary spacecraft.

This research and product development will have applications in combustion, propulsion, engines, materials synthesis, energetics, and other reacting flow systems. The advanced measurement system also represents game-changing diagnostics capability that will play a significant role in advancing predictive modeling in a wide range of applications associated with multiphase flows.