Engineering topics
Schwarz, Carol
Publications and source records attributed to Schwarz, Carol.
High-Grading Lunar Samples
Astronauts on long-duration lunar missions will need the capability to high-grade their samples to select the highest value samples for transport to Earth and to leave others on the Moon. We are supporting studies to define the necessary and sufficient measurements and techniques for high-grading samples at a lunar outpost. A glovebox, dedicated to testing instruments and techniques for high-grading samples, is in operation at the JSC Lunar Experiment Laboratory. A reference suite of lunar rocks and soils, spanning the full compositional range found in the Apollo collection, is available for testing in this laboratory. Thin sections of these samples are available for direct comparison. The Lunar Sample Compendium, on-line at http://www-curator.jsc.nasa.gov/lunar/compendium.cfm, summarizes previous analyses of these samples. The laboratory, sample suite, and Compendium are available to the lunar research and exploration community. In the first test of possible instruments for lunar sample high-grading, we imaged 18 lunar rocks and four soils from the reference suite using the Multispectral Microscopic Imager (MMI) developed by Arizona State University and JPL (see Farmer et. al. abstract). The MMI is a fixed-focus digital imaging system with a resolution of 62.5 microns/pixel, a field size of 40 x 32 mm, and a depth-of-field of approximately 5 mm. Samples are illuminated sequentially by 21 light emitting diodes in discrete wavelengths spanning the visible to shortwave infrared. Measurements of reflectance standards and background allow calibration to absolute reflectance. ENVI-based software is used to produce spectra for specific minerals as well as multi-spectral images of rock textures.
Lithological Variation with Depth and Decoupling of Maturity Parameters in Apollo 16 Regolith Core 68001/2
Using FerroMagnetic Resonance (FMR) and Instrumental Neutron Activation Analysis (INAA), we have determined the maturity (surface exposure) parameter I(sub s)/FeO and concentrations of twenty- five chemical elements on samples taken every half centimeter down the 61-cm length of the 68001/2 regolith core (double drive tube) collected at station 8 on the Apollo 16 mission to the Moon. Contrary to premission expectations, no ejecta or other influence from South Ray crater is evident in the core, although a small inflection in the I(sub s)/FeO profile at 3 cm depth may be related the South Ray crater impact. Regolith maturity generally decreases with depth, as in several previously studied cores. We recognize five compositionally distinct units in the core, which we designate A through E, although all are similar in composition to each other and to other soils from the Cayley plains at the Apollo 16 site. Unit A (0-33 cm) is mature to submature throughout (I(sub s)/FeO: 89-34 units) and is indistinguishable in composition from surface soils collected at station 8. Unit B (33-37 cm) is enriched slightly in a component of anorthositic norite composition. Unit D (42-53 cm) is compositionally equivalent to 80 wt% Unit-A soil plus 20 wt% Apollo-16-type dimict breccia consisting of subequal parts anorthosite and impact-melt breccia. Compared to Unit A, Unit E (53-61 cm) contains a small proportion (up to 4%) of some component compositionally similar to Apollo 14 sample 14321. Unit C (37-42 cm) is unusual. For lithophile and siderophile elements, it is similar to Units A and D. However, I(sub s)/FeO is low throughout the unit (less than 30 units) and in a bluish-gray zone at 41 cm depth I(sub s)/FeO drops to 1.6 units, the lowest value that we have observed in several hundred Apollo 16 soil samples. Samples from the bluish-gray zone also have low Zn concentrations, less than 10 micro g/g, compared to 20-30 micro g/g for the rest of the core. Although both values are consistent with fragmented rock material that has received virtually no surface exposure, the abundance of agglutinates in the bluish-gray soil of Unit C is moderately high, typical of a submature soil that would ordinarily have I(sub s)/FeO - 30. We believe that the anomalously low values of I(sub s)/FeO and Zn concentration result because the soil was heated to -800-1000 'C, probably during an impact. This temperature range is sufficient to volatize the surface-correlated Zn and agglomerate the nanophase metal giving rise to the FMR signal but is not great enough to sinter the soil. Alternatively, the unusual soil interval may represent a disaggregated or incipient regolith breccia, although there is no significant difference in the texture or clast-matrix relationships between Unit C and adjacent units.
Preliminary description of double drive tube 68002/68001
Apollo 16 double drive tube 68002/68001 has been opened, and information on its contents and structure is now available. The sample was taken in Apr. 1972 at Station 8, a gently undulating surface of South Ray Crater ejecta material. The tube was driven into the surface about 2 m from the edge of a 10-15 m diameter crater in an area where small (less than 0.5 m diameter) craters are common. Fragments of the less than 1 cm diameter size are most abundant in this area. The top section, 68002, and the lower section, 68001, have a combined length of about 61 cm.
MacAlpine Hills 88104 and 88105 lunar highland meteorites - General description and consortium overview
MacAlpine Hills 88104 and 88105 meteorites found in nearby locations in Antarctica, which are considered to be pieces of the same meteorite, are described. MAC88104/5 is an anorthositic breccia consisting of numerous small clasts in a glassy matrix. A summary list of lunar meteorites and a review of consortium research are presented.