Sample crushing, sieving, metering, and Distribution System

This paper describes development and testing of the Precision Sample Metering and Distribution System (PSMDS), an automated system for crushing, sieving, metering, and distributing of samples to scientific instruments. The crushing is achieved via combined effect of compression and attrition. The subsequent sieving and transport of crushed powered into a metering device is done pneumatically. Sieving uses a 150 micron sieve inside a Gas Jet Sieve, a size requirement driven by CheMin instrument on MSL mission. The sample is gravity fed into sample cups, and a vibrating feed tube allows accurate metering of sample volume. The PSMDS was tested at Mars pressures and CO2 atmosphere and produced the intended end-to-end result. The metered samples averaged 0.234 grams with standard deviation of 0.05 gram. Cross-contamination between samples was mitigated by processing two "throwaway" samples to clear out contaminating material.