18 NASA Tech Briefs, July 2010 Lunar Soil Particle Separator John H. Glenn Research Center, Cleveland, Ohio The Lunar Soil Particle Separator (LSPS) beneficiates soil prior to in situ resource utilization (ISRU). It can im- prove ISRU oxygen yield by boosting the concentration of ilmenite, or other iron-oxide-bearing materials found in lunar soils, which can substantially re- duce hydrogen reduction reactor size, as well as drastically decreasing the power input required for soil heating. LSPS particle size separations can be performed to “de-dust” regolith, and to improve ISRU reactor flow dynamics. LSPS mineral separations can be used to alter the sintering characteristics of lunar soil, and can also be used to sepa- rate and concentrate lunar materials useful for manufacture of structural ma- terials, glass, and chemicals. An initial centrifugal particle size sep- aration is integrated by the LSPS and is followed by magnetic, gravity, and/or electrostatic separations. LSPS hardware for each unit operation exhibits favor- able properties of low mass and low power requirements. A single feeder de- livers soil to the system where sorted par- ticles cascade by gravity to the next unit operation, or to product collection bins. The centrifugal particle separator avoids the use of heavy, eccentric drives that re- quire high power input, and does not re- quire the use of screens that can plug with near-size particles. The magnetic separator uses high-strength, permanent magnets and requires power only to ro- The planned Mars Science Laboratory mission requires inlet funnels for chan- neling unconsolidated powdered sam- ples from the sampling and sieving mechanisms into instrument test cells, which are required to reduce cross-con- tamination of the samples and to mini- mize residue left in the funnels after each sample transport. To these ends, a solid-state shaking mechanism has been created that requires low power and is lightweight, but is sturdy enough to sur- vive launch vibration. The funnel mechanism is driven by asymmetrically mounted, piezoelectric flexure actuators that are out of the load path so that they do not support the funnel mass. Each actuator is a tita- nium, flextensional piezoelectric device driven by a piezoelectric stack. The stack has Invar endcaps with a half- spherical recess. The Invar is used to counteract the change in stress as the actuators are cooled to Mars’ ambient temperatures. A ball screw is threaded through the actuator frame into the re- cess to apply pre-stress, and to trap the piezoelectric stack and endcaps in flex- ure. During the vibration cycle of the flextensional actuator frame, the com- pression in the piezoelectric stack may decrease to the point that it is un- stressed; however, because the ball joint cannot pull, tension in the piezoelectric stack cannot be produced. The actua- tors are offset at 120°. In this flight de- sign, redundancy is required, so three actuators are used though only one is needed to assist in the movement. The funnel is supported at three con- tact points offset to the hexapod support contacts. The actuator surface that does not contact the ring is free to expand. Two other configurations can be used to mechanically tune the vibration. The free end can be designed to drive a fixed mass, or can be used to drive a free mass to ex- cite impacts (see figure). Tests on this fun- nel mechanism show a high density of res- onance modes between 1 and 20 kHz. A subset of these between 9 and 12 kHz was used to drive the CheMin actuators at 7 V peak to peak. These actuators could be driven by a single resonance, or swept through a frequency range to decrease the possibility that a portion of the funnel surface was not coincident with a nodal line (line of no displacement). The frequency of actuation can be electrically controlled and monitored and can also be mechanically tuned by the addition of tuning mass on the free end of the actuator. The devices are solid-state and can be designed with no macroscopically moving parts. This de- sign has been tested in a vacuum at both Mars and Earth ambient temperatures ranging from –30 to 25 ºC. This work was done by Stewart Sherrit; Curtis E Tucker, Jr.; John Frankovich, and Xiaoqi Bao of Caltech for NASA’s Jet Propulsion Laboratory. Further informa- tion is contained in a TSP (see page 1). NPO-45856 A graphic of the Actuator Mechanism mounted on the funnel rim out of the load path. The other end of the flexure can be modified to (a) be free, (b) drive a fixed mass, or (c) drive a free mass at low resonance and produce impacts. (c.) (b.) (a.) Miniature Piezoelectric Shaker for Distribution of Unconsoli- dated Samples to Instrument Cells This design could be applicable for handling powders in the pharmaceutical industry. NASA’s Jet Propulsion Laboratory, Pasadena, California https://ntrs.nasa.gov/search.jsp?R=20100024432 2020-06-15T13:06:20+00:00Z