Modeling Sensor Radiance Modifications due to Dust Clouds from Plume Surface Interactions

Dust and regolith particles liberated by Plume-Surface Interactions (PSI) during spacecraft propulsive landing on the unprepared regolith of the Moon, Mars, and other destinations result in damaging debris and navigation sensor impairment. Obscuration of landing area features and the deterioration of sensor signals as they propagate through plumes gases, dust clouds, and dense high-speed near-surface sheets of regolith particles constitute serious risks for safe navigation and landing hazard detection systems. In this effort, CFD Research will team up with University of Central Florida to develop a computational modeling capability for predicting the adverse effects on sensor radiances as they propagate through the plume gas and particle cloud regions between the lander and ground. Existing two-fluid gas-granular simulation tools that provide the spatial definition of lander plume gas and particle cloud obscurants will be coupled with an advanced atmospheric radiative transfer simulation tools capable of accounting also for polarization over a wide spectral range from millimeter through infrared waves of interest. Line-by-line spectral properties for gases, and accurate T-matrix based absorption and scattering cross sections for the particulate clouds will be utilized to account for the complex lunar or other planetary regolith shapes and material properties. Application testing and validation of the resulting sensor signal propagation predictive capability will be performed against the UCF developed EjectaSTORM sensor system which is currently being tested in terrestrial landing experiments on a Masten lander and destined to deliver flight data on a future CLPS lander mission. The resulting tools will be delivered to NASA as an open-source tool for ready utilization to support safe landing sensor system development for lunar and Martian landers, including the Human Lander System.