Development of the Dust Ejecta Radar Technology (DERT) to Determine Plume-Surface Interaction Ejecta Velocities on Planetary Surfaces

Here we present a novel use of millimeter wave doppler radar to measure the velocity of ejecta generated by the impingement of rocket plumes on a planetary surface. The Dust Ejecta Radar Technology (DERT) provides a unique dataset based on direct measurements of ejecta particle velocities during plume-surface interactions. DERT is a continuous wave (CW) 94GHz radar unit that is being developed at Kennedy Space Center. DERT has measured velocities of a pendulum $(\sim 1 \mathrm{~m}/\mathrm{s})$, a rotating strip $(60 \mathrm{~m}/\mathrm{s})$, projected regolith simulant BP-1 $(\sim 250 \mathrm{~m}/\mathrm{s})$ and rifle rounds $(-820 \mathrm{~m}/\mathrm{s})$. Signal-to-Noise Ratios of up to 60 dB have been demonstrated. Data collected from DERT will inform the development of high-fidelity computational models of plume-surface interaction effects and will help address NASA Strategic Knowledge Gaps related to characterizing entry, descent and landing effects, and the risks associated with high-speed ejecta on the lander and lunar surface assets.