High spatio-temporal resolution particle sizer for plume-induced ejecta clouds

This Phase II SBIR project addresses a Strategic Knowledge Gap by developing a lander-mounted system to determine particle size distribution in lander plumes. Plume-Surface-Interactions (PSI) in supersonic, highly rarefied, low gravity environments remain poorly understood. Temporally and spatially variable particle size distributions in lunar ejecta have never been measured accurately. Estimates depend heavily on assumptions and modeling, for which accurate empirical input data from landers is critically needed to predict and prevent damage. Knowledge of particle size distributions in lander plumes will be vital to the coming Gateway and Moon to Mars missions.nbsp; Hence, our instrument and method represent a Game Changing Development. The method determines laser beam propagation decay constants at multiple wavelengths from imaged light scatter. Phase I showed that various relevant distributions could be determined from knowledge of beam decay constants at as few as four wavelengths. nbsp;We will develop and test the theory and calculation methods to obtain particle size distributions from beam propagation decay, determine accuracy of the calculation results and effects of uncertainty, and develop on-board automated image and data processing.nbsp; We will perform experiments on laboratory scattering standards to confirm methods for acquiring beam propagation decay constants and transformation into particle distributions, including relevant particle sizes, mineral mixtures, spatial inhomogeneities, and dynamic particle clouds in vacuum with Lunar simulant.nbsp; System engineering will select and acquire lasers and cameras for a system prototype, design and fabricate low SWaP system packaging, and design a system mount that simulates a lander platform for lab and field tests.nbsp; Preparation for flight testing will specify a system configuration, complete a Payload Flight Request, and fabricate the system prototype for Phase II E flight tests.