AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Electrostatic Collection of Tribocharged Lunar Dust Simulants at Elevated Vacuum Levels
NIMA AFSHAR-MOHAJER, Chang-Yu Wu, Nicoleta Sorloacia-Hickman, University of Florida
Abstract Number: 491 Working Group: Control Technology
Abstract Deposition of the naturally charged particles on the lunar surface was troublesome in previous NASA explorations. Developing control technologies for mitigating dust deposition in limiting condition of the lunar atmosphere is imperative for any future space exploration. This study reports experimental investigation of the collection efficiency of an electrostatic lunar dust collector (ELDC). A dual-functional remotely controlled particle charger/dropper was designed for tribocharging 20-µm lunar dust simulants using aluminum surfaces, and a system of Faraday cup connected to an electrometer working in nC charge range was used to measure the particle charges. First, tribochargeability of the lunar dust simulants at three vacuum levels was studied, and the process was found to be the most effective with the JSC-1A samples. Estimation of ELDC collection efficiency as a function of applied voltage was achieved through implementing two separate experimental designs to study the effect of low vacuum (~0.1 Torr) and high vacuum (~0.0001 Torr) on the created particle charge and the ELDC collection efficiency at four different voltages. For the tested range of electrostatic field strength (0.66 to 2.6 kV/m), the mass-based and charge-based approaches used in determining the collection efficiencies obtained the range of 0.25 to 0.75% and 0.35 to 1.05% for the low vacuum, and 9 to 42% and 12 to 54% for the high vacuum conditions. The linear relationship between the applied voltage and ELDC collection efficiency predicted by the previous model was confirmed, and the collection pattern of the collected particles over the collection plate was consistent with the previously computed charge distribution on the collection plate. Aside from validating the predictability of the developed theoretical model, this study offers a novel method of particle charging inside vacuum chambers with a variety of applications for studying chargeability of particles at different temperatures and pressures.