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A laboratory study was performed using the Visible Oxford Space Environment Goniometer in which the broadband (350–1250 nm) bidirectional reflectance distribution functions (BRDFs) of two representative Apollo regolith samples were measured, for two surface roughness profiles, across a range of viewing angles—reflectance: 0–70°, in steps of 5°; incidence: 15°, 30°, 45°, and 60°; and azimuthal: 0°, 45°, 90°, 135°, and 180°. The BRDF datasets were fitted using the Hapke BRDF model to (1) provide a method of comparison to other photometric studies of the lunar regolith and (2) to produce Hapke parameter values which can be used to extrapolate the BRDF to all angles. Importantly, the surface profiles of the samples were characterized using an Alicona 3D® instrument, allowing two of the free parameters within the Hapke model, φ and θ¯$$ \overline{\theta} $$, which represent porosity and surface roughness, respectively, to be constrained. The study determined that, for θ¯$$ \overline{\theta} $$, the 500–1000 μm size‐scale is the most relevant for the BRDF. Thus, it deduced the following “best fit” Hapke parameters for each of the samples: Apollo 11 rough—w$$ w $$ = 0.315 ± 0.021, b$$ b $$ = 0.261 ± 0.007, and hS$$ {h}_S $$ = 0.039 ± 0.005 (with θ¯$$ \overline{\theta} $$ = 21.28° and φ = 0.41 ± 0.02); Apollo 11 smooth—w$$ w $$ = 0.281 ± 0.028, b$$ b $$ = 0.238 ± 0.008, and hS$$ {h}_S $$ = 0.032 ± 0.006 (with θ¯$$ \overline{\theta} $$ = 13.80° and φ = 0.60 ± 0.02); Apollo 16 rough—w$$ w $$ = 0.485 ± 0.155, b$$ b $$ = 0.155 ± 0.083, and hS$$ {h}_S $$ = 0.135 ± 0.007 (with θ¯$$ \overline{\theta} $$ = 21.69° and φ = 0.55 ± 0.02); Apollo 16 smooth—w$$ w $$ = 0.388 ± 0.057, b$$ b $$ = 0.063 ± 0.033, and hS$$ {h}_S $$ = 0.221 ± 0.011 (with θ¯$$ \overline{\theta} $$ = 14.27° and φ = 0.40 ± 0.02). Finally, updated hemispheric albedo functions were determined for the samples, which can be used to set laboratory measured visible scattering functions within thermal models. [ABSTRACT FROM AUTHOR]

The meta-analysis referenced in the "Obstructive Sleep Apnea" section should instead refer to a meta-analysis for chronic kidney disease. Additionally, there are two mis-numbered reference citations in the "chronic kidney disease" section (ref. 107 should ref. 104 [Wang C et al. 2014] and ref. 105. [ABSTRACT FROM AUTHOR]

Understanding how the surfaces of airless planetary bodies—such as the Moon—scatter visible light enables constraints to be placed on their surface properties and top boundary layer inputs to be set within thermal models. Remote sensing instruments—such as Diviner onboard the Lunar Reconnaissance Orbiter—measure thermal emission and visible light scattering functions across visible (∼0.38–0.7 µm) to thermal infrared (TIR) wavelengths (∼0.7–350 μm). To provide ground support measurements for such instruments, the Oxford Space Environment Goniometer (OSEG) was built. Initially, the OSEG focused on measuring TIR directional emissivity functions for regolith and regolith simulant samples in a simulated space environment, but it has recently been modified to measure visible wavelength Bidirectional Reflectance Distribution Functions (BRDFs) of samples in ambient conditions. Laboratory-measured BRDFs can be used (1) to test and to help interpret models—such as the Hapke photometric model—and (2) as visible scattering function inputs for thermal models. This paper describes the modifications to and initial calibration measurements taken by the Visible Oxford Space Environment Goniometer with a 532 nm laser, and details how this setup can be used to measure BRDFs of regolith and regolith simulant samples of airless planetary bodies. [ABSTRACT FROM AUTHOR]

The InSight mission is due to launch in May 2018, carrying a payload of novel instruments designed and tested to probe the interior of Mars whilst deployed directly on the Martian regolith and partially isolated from the Martian environment by the Wind and Thermal Shield. Central to this payload is the seismometry package SEIS consisting of two seismometers, which is supported by a suite of environmental/meteorological sensors (Temperature and Wind Sensor for InSight TWINS; and Auxiliary Payload Sensor Suite APSS). In this work, an optimal estimations inversion scheme which aims to decorrelate the short-period seismometer (SEIS-SP) signal due to seismic activity alone from the environmental signal and random noise is detailed, and tested on both simulated and Viking data. This scheme also applies a module to identify measurements contaminated by Single Event Phenomena (SEP). This scheme will be deployed as the pre-processing pipeline for all SEIS-SP data prior to release to the scientific community for analysis. [ABSTRACT FROM AUTHOR]

Electrostatic forces from asteroidal photoelectron emission both redistribute regolith and modulate the surface particle size distribution. A 2D particle-in-cell code has been developed to investigate the possibility of direct measurement of the electrical environment near the surface of an asteroid during a sample return mission. The spacecraft is expected to reach equilibrium with the surface photoelectron layer in , which is rapid compared to the descent timescale, permitting the simulation equilibria to be assumed representative of the dynamic spacecraft environment. Typical signals on a set of spacecraft-mounted sampling electrodes during descent are presented. The distorting effect of the spacecraft significantly modifies the potential on any sensing electrodes by introducing an equipotential body; creating a shadow; and photoemitting itself. Optimal locations for mounting the electrodes to measure the asteroid?s surface electric field are suggested, where the potential differences measured are expected to be both readily detectable and representative of the local electrostatic environment. The high electron concentration near the surface is likely to ensure that the spacecraft and surface potential are similar at touchdown, in the absence of other charging effects, such as those introduced by the sampling mechanism. This study was carried out for an asteroid at 3AU, but enhanced photoemission will increase the likelihood of electrostatic regolith disturbance by the spacecraft shadow during descent to an object nearer the Sun. [ABSTRACT FROM AUTHOR]

Abstract: New measurements of the low-temperature near-infrared absorption of methane (Sihra, 1998, Laboratory measurements of near-infrared methane bands for remote sensing of the jovian atmosphere, Ph.D. thesis, University of Oxford) have been combined with existing, longer path-length, higher-temperature data of Strong et al. (1993, Spectral parameters of self- and hydrogen-broadened methane from 2000 to 9500 cm−1 for remote sounding of the atmosphere of Jupiter, J. Quant. Spectrosc. Radiat. Trans. 50, 309–325) and fitted with band models. The combined data set is found to be more consistent with previous low-temperature methane absorption measurements than that of Strong et al. (1993, J. Quant. Spectrosc. Radiat. Trans. 50, 309–325) but covers the same wider wavelength range and accounts for both self- and hydrogen-broadening conditions. These data have been fitted with k-coefficients in the manner described by Irwin et al. (1996, Calculated k-distribution coefficients for hydrogen- and self-broadened methane in the range 2000–9500 cm−1 from exponential sum fitting to band modelled spectra, J. Geophys. Res. 101, 26,137–26,154) and have been used in multiple-scattering radiative transfer models to assess their impact on our previous estimates of the jovian cloud structure obtained from Galileo Near-Infrared Mapping Spectrometer (NIMS) observations (Irwin et al., 1998, Cloud structure and atmospheric composition of Jupiter retrieved from Galileo NIMS real-time spectra, J. Geophys. Res. 103, 23,001–23,021; Irwin et al., 2001, The origin of belt/zone contrasts in the atmosphere of Jupiter and their correlation with 5-μm opacity, Icarus 149, 397–415; Irwin and Dyudina, 2002, The retrieval of cloud structure maps in the equatorial region of Jupiter using a principal component analysis of Galileo/NIMS data, Icarus 156, 52–63). Although significant differences in methane opacity are found at cooler temperatures, the difference in the optical depth of the atmosphere due to methane is found to diminish rapidly with increasing pressure and temperature and thus has negligible effect on the cloud structure inferred at deeper levels. Hence the main cloud opacity variation is still found to peak at around 1–2 bar using our previous analytical approach, and is thus still in disagreement with Galileo Solid State Imager (SSI) determinations (Banfield et al., 1998, Jupiter''s cloud structure from Galileo imaging data, Icarus 135, 230–250; Simon-Miller et al., 2001, Color and the vertical structure in Jupiter''s belts, zones and weather systems, Icarus 154, 459–474) which place the main cloud deck near 0.9 bar. Further analysis of our retrievals reveals that this discrepancy is probably due to the different assumptions of the two analyses. Our retrievals use a smooth vertically extended cloud profile while the SSI determinations assume a thin NH3 cloud below an extended haze. When the main opacity in our model is similarly assumed to be due to a thin cloud below an extended haze, we find the main level of cloud opacity variation to be near the 1 bar level—close to that determined by SSI and moderately close to the expected condensation level of ammonia ice of 0.85 bar, assuming that the abundance of ammonia on Jupiter is (Folkner et al., 1998, Ammonia abundance in Jupiter''s atmosphere derived from the attenuation of the Galileo probe''s radio signal, J. Geophys. Res. 103, 22,847–22,855; Atreya et al., 1999, A comparison of the atmospheres of Jupiter and Saturn: deep atmospheric composition, cloud structure, vertical mixing, and origin, Planet. Space Sci. 47, 1243–1262). However our data in the 1–2.5 μm range have good height discrimination and our lowest estimate of the cloud base pressure of 1 bar is still too great to be consistent with the most recent estimates of the ammonia abundance of 3.5 × solar. Furthermore the observed limited spatial distribution of ammonia ice absorption features on Jupiter suggests that pure ammonia ice is only present in regions of localised vigorous uplift (Baines et al., 2002, Fresh ammonia ice clouds in Jupiter: spectroscopic identification, spatial distribution, and dynamical implications, Icarus 159, 74–94) and is subsequently rapidly modified in some way which masks its pure absorption features. Hence we conclude that the main cloud deck on Jupiter is unlikely to be composed of pure ammonia ice and instead find that it must be composed of either NH4SH or some other unknown combination of ammonia, water, and hydrogen sulphide and exists at pressures of between 1 and 2 bar. [Copyright &y& Elsevier]

The CM carbonaceous chondrites are an important resource in our efforts to understand the role of volatiles in the formation of planetary systems. We report the bulk mineralogy, water abundance, and infrared (IR) reflectance spectra of the CM chondrites LaPaz Icefield (LAP) 04514, LAP 04796, LAP 04565, and LAP 02333. They contain abundant Fe‐ and Mg‐rich serpentines (~70–80 vol%), and based on their phyllosilicate fractions, we classify LAP 04514, LAP 04796, and LAP 04565 as petrologic subtype 1.6 and LAP 02333 as 1.4. This is consistent with estimated water abundances of 9.9 (±1.1) wt% for LAP 04796, 10.4 (±0.1) wt% for LAP 04565, and 11.5 (±0.5) wt% for LAP 02333. However, LAP 04514 contains less water (8.8 ± 0.3 wt%), has a shallower 3 µm band depth, and lacks tochilinite having experienced posthydration temperatures of ~300–400 °C. We conclude that LAP 04514, LAP 04796, and LAP 04565 are among the least altered CM chondrites, which retain primitive features from the initial building blocks of the CM parent body. Finally, we use the IR spectral features of LAP 04514, LAP 04796, and LAP 04565 to identify C‐complex asteroid surfaces that record mild levels of hydration. [ABSTRACT FROM AUTHOR]

The highly hydrated, petrologic type 1 CM and CI carbonaceous chondrites likely derived from primitive, water‐rich asteroids, two of which are the targets for JAXA's Hayabusa2 and NASA's OSIRIS‐REx missions. We have collected visible and near‐infrared (VNIR) and mid infrared (MIR) reflectance spectra from well‐characterized CM1/2, CM1, and CI1 chondrites and identified trends related to their mineralogy and degree of secondary processing. The spectral slope between 0.65 and 1.05 μm decreases with increasing total phyllosilicate abundance and increasing magnetite abundance, both of which are associated with more extensive aqueous alteration. Furthermore, features at ~3 μm shift from centers near 2.80 μm in the intermediately altered CM1/2 chondrites to near 2.73 μm in the highly altered CM1 chondrites. The Christiansen features (CF) and the transparency features shift to shorter wavelengths as the phyllosilicate composition of the meteorites becomes more Mg‐rich, which occurs as aqueous alteration proceeds. Spectra also show a feature near 6 μm, which is related to the presence of phyllosilicates, but is not a reliable parameter for estimating the degree of aqueous alteration. The observed trends can be used to estimate the surface mineralogy and the degree of aqueous alteration in remote observations of asteroids. For example, (1) Ceres has a sharp feature near 2.72 μm, which is similar in both position and shape to the same feature in the spectra of the highly altered CM1 MIL 05137, suggesting abundant Mg‐rich phyllosilicates on the surface. Notably, both OSIRIS‐REx and Hayabusa2 have onboard instruments which cover the VNIR and MIR wavelength ranges, so the results presented here will help in corroborating initial results from Bennu and Ryugu. [ABSTRACT FROM AUTHOR]

The northern floor and wall of Amundsen crater, near the lunar south pole, is a permanently shaded region (PSR). Previous study of this area using data from the Lunar Orbiter Laser Altimeter (LOLA), Diviner and LAMP instruments aboard Lunar Reconnaissance Orbiter (LRO) shows a spatial correlation between brighter 1064 nm albedo, annual maximum surface temperatures low enough to enable persistence of surface water ice (<110 K), and anomalous ultraviolet radiation. We present results using data from Diviner that quantify the differential emissivities observed in the far-IR (near the Planck peak for PSR-relevant temperatures) between the PSR and a nearby non-PSR target in Amundsen Crater. We find features in far-IR emissivity (50–400 μm) could be attributed to either, or a combination, of two effects (i) differential regolith emissive behavior between permanently-shadowed temperature regimes and those of normally illuminated polar terrain, perhaps related to presence of water frost (as indicated in other studies), or (ii) high degrees of anisothermality within observation fields of view caused by doubly-shaded areas within the PSR target that are colder than observed brightness temperatures. The implications in both cases are compelling: The far-IR emissivity curve of lunar cold traps may provide a metric for the abundance of "micro" cold traps that are ultra-cool, i.e. shadowed also from secondary and higher order radiation (absorption and re-radiation or scattering by surrounding terrain), or for emissive properties consistent with the presence of surface water ice. • We explore far-IR emissivity of permanently- and partially- shaded targets in the lunar south polar crater Amundsen. • 50–400 micron emissivity trends of the permanently shadowed region (PSR) target are different than for the non-PSR target. • Unlike the non-PSR target, emissivity of the PSR target shows apparent temperature dependence between ~30–40 K. • Results are consistent with anisothermality due to sub-FOV scale ultra-cold terrain, and surface water ice. [ABSTRACT FROM AUTHOR]

Abstract We describe Castalia , a proposed mission to rendezvous with a Main Belt Comet (MBC), 133P/Elst-Pizarro. MBCs are a recently discovered population of apparently icy bodies within the main asteroid belt between Mars and Jupiter, which may represent the remnants of the population which supplied the early Earth with water. Castalia will perform the first exploration of this population by characterising 133P in detail, solving the puzzle of the MBC's activity, and making the first in situ measurements of water in the asteroid belt. In many ways a successor to ESA's highly successful Rosetta mission, Castalia will allow direct comparison between very different classes of comet, including measuring critical isotope ratios, plasma and dust properties. It will also feature the first radar system to visit a minor body, mapping the ice in the interior. Castalia was proposed, in slightly different versions, to the ESA M4 and M5 calls within the Cosmic Vision programme. We describe the science motivation for the mission, the measurements required to achieve the scientific goals, and the proposed instrument payload and spacecraft to achieve these. [ABSTRACT FROM AUTHOR]