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Economic parameters are identified for an in-space industry where the capital is made on one planet, it is transported to and teleoperated on a second planet, and the product is transported off the second planet for consumption. This framework is used to model the long-run cost of lunar propellant production to help answer whether it is commercially competitive against propellant launched from Earth. The prior techno-economic analyses (TEAs) of lunar propellant production had disagreed over this. The "gear ratio on cost" for capital transport, G , and the production mass ratio of the capital, φ , are identified as the most important factors determining competitiveness. The prior TEAs are examined for how they handled these two metrics. This identifies crucial mistakes in some of the TEAs: choosing transportation architectures with high G , and neglecting to make choices for the capital that could achieve adequate φ. The tent sublimation technology has a value of φ that is an order of magnitude better than the threshold for competitiveness even in low Earth orbit (LEO). The strip mining technology is closer to the threshold, but technological improvements plus several years of operating experience will improve its competitiveness, according to the model. Objections from members of the aerospace community are discussed, especially the question whether the technology can attain adequate reliability in the lunar environment. The results suggest that lunar propellant production will be commercially viable and that it should lower the cost of doing everything else in space. • Econometrics are developed for multi-planet industry. • Modeling is developed for the long run average cost of lunar propellant. • Lunar-derived propellant can out-compete Earth-launched propellant. • To be competitive, lunar capital must produce ≳35 times its mass in product. • Long-term reliability of the lunar capital is the primary remaining concern. [ABSTRACT FROM AUTHOR]

Multiple nations are planning activity on the Moon's surface, and to deconflict lunar operations we must understand the sandblasting damage from rocket exhaust blowing soil. Prior research disagreed over the scaling of the erosion rate, which determines the magnitude of the damage. Reduced gravity experiments and two other lines of evidence now indicate that the erosion rate scales with the kinetic energy flux at the bottom of the laminar sublayer of the gas. Because the rocket exhaust is so fast, eroded particles lifted higher in the boundary layer do not impact the surface for kilometers (if at all; some leave the Moon entirely), so there is no saltation in the vicinity of the gas. As a result, there is little transport of gas kinetic energy from higher in the boundary layer down to the surface, so the emission of soil into the gas is a surprisingly low energy process. In low lunar gravity, a dominant source of resistance to this small energy flux turns out to be the cohesive energy density of the lunar soil, which arises primarily from particles in the 0.3 to 3 μ m size range. These particles constitute only a tiny fraction of the mass of lunar soil and have been largely ignored in most studies, so they are poorly characterized. • Reduced gravity erosion experiments produced insight into the physics. • Roberts' theory of soil erosion under landing rockets is incorrect. • Erosion under a rocket plume is a surprisingly low energy phenomenon. • Erosion rate scales with energy flux in the laminar sublayer, not shear stress. [ABSTRACT FROM AUTHOR]

In the companion paper ("Erosion rate of lunar soil under a landing rocket, part 1: identifying the rate-limiting physics", this issue) an equation was developed for the rate that lunar soil erodes under the exhaust of a landing rocket. That equation has only one parameter that is not calibrated from first principles, so here it is calibrated by the blowing soil's optical density curve during an Apollo landing. An excellent fit is obtained, helping validate the equation. However, when extrapolating the erosion rate all the way to touchdown on the lunar surface, a soil model is needed to handle the increased resistance to erosion as the deeper, more compacted soil is exposed. Relying on models derived from Apollo measurements and from Lunar Reconnaissance Orbiter (LRO) Diviner thermal inertia measurements, only one additional soil parameter is unknown: the scale of increasing cohesive energy with soil compaction. Treating this as an additional fitting parameter results in some degeneracy in the solutions, but the depth of erosion scour in the post-landing imagery provides an additional constraint on the solution. The results show that about 4 to 10 times more soil was blown in each Apollo landing than previously believed, so the potential for sandblasting damage is worse than prior estimates. This also shows that, with further development, instruments to measure the soil erosion during lunar landings can constrain the soil column's density profile complementary to the thermal inertia measurements, providing insight into the landing site's geology. • A new erosion rate theory is compared to dust blown in the Apollo 16 landing. • The theory correctly predicts the blowing dust's optical density curve. • A soil model is needed to predict erosion after the loose layer is removed. • Eleven to 26 tons of soil were blown, 4 to 10 times the prior estimates. • Soil blown by lunar landings is a worse problem than previously believed. [ABSTRACT FROM AUTHOR]

Highlights • The literature on asteroid classification is reviewed from 1801 to the present. • Scientists considered asteroids to be planets until the 1950s. • Thousands of asteroids sharing orbits was not debarring from planet status. • They were reclassified as non-planets on the basis of geophysical characteristics. • Taxonomical terms like planet are determined by the scientific process, not voting. Abstract It is often claimed that asteroids' sharing of orbits is the reason they were re-classified from planets to non-planets. A critical review of the literature from the 19th Century to the present shows this is factually incorrect. The literature shows the term asteroid was broadly recognized as a subset of planet for 150 years. On-going discovery of asteroids resulted in a de facto stretching of the concept of planet to include the ever-smaller bodies. Scientists found utility in this taxonomic identification as it provided categories needed to argue for the leading hypothesis of planet formation, Laplace's nebular hypothesis. In the 1950s, developments in planet formation theory found it no longer useful to maintain taxonomic identification between asteroids and planets, Ceres being the primary exception. At approximately the same time, there was a flood of publications on the geophysical nature of asteroids showing them to be geophysically different than the large planets. This is when the terminology in asteroid publications calling them planets abruptly plunged from a high level of usage where it had hovered during the period 1801–1957 to a low level that held constant thereafter. This marks the point where the community effectively formed consensus that asteroids should be taxonomically distinct from planets. The evidence demonstrates this consensus formed on the basis of geophysical differences between asteroids and planets, not the sharing of orbits. We suggest attempts to build consensus around planetary taxonomy not rely on the non-scientific process of voting, but rather through precedent set in scientific literature and discourse, by which perspectives evolve with additional observations and information, just as they did in the case of asteroids. [ABSTRACT FROM AUTHOR]

The national space programs have an historic opportunity to help solve the global-scale economic and environmental problems of Earth while becoming more effective at science through the use of space resources. Space programs will be more cost-effective when they work to establish a supply chain in space, mining and manufacturing then replicating the assets of the supply chain so it grows to larger capacity. This has become achievable because of advances in robotics and artificial intelligence. It is roughly estimated that developing a lunar outpost that relies upon and also develops the supply chain will cost about 1/3 or less of the existing annual budgets of the national space programs. It will require a sustained commitment of several decades to complete, during which time science and exploration become increasingly effective. At the end, this space industry will capable of addressing global-scale challenges including limited resources, clean energy, economic development, and preservation of the environment. Other potential solutions, including nuclear fusion and terrestrial renewable energy sources, do not address the root problem of our limited globe and there are real questions whether they will be inadequate or too late. While industry in space likewise cannot provide perfect assurance, it is uniquely able to solve the root problem, and it gives us an important chance that we should grasp. What makes this such an historic opportunity is that the space-based solution is obtainable as a side-benefit of doing space science and exploration within their existing budgets. Thinking pragmatically, it may take some time for policymakers to agree that setting up a complete supply chain is an achievable goal, so this paper describes a strategy of incremental progress. The most crucial part of this strategy is establishing a water economy by mining on the Moon and asteroids to manufacture rocket propellant. Technologies that support a water economy will play an important role leading toward space development. [ABSTRACT FROM AUTHOR]

A technique to estimate mass erosion rate of surface soil during landing of the Apollo Lunar Module (LM) and total mass ejected due to the rocket plume interaction is proposed and tested. The erosion rate is proportional to the product of the second moment of the lofted particle size distribution N(D), and third moment of the normalized soil size distribution S(D), divided by the integral of S(D)⋅D2/v(D), where D is particle diameter and v(D) is the vertical component of particle velocity. The second moment of N(D) is estimated by optical extinction analysis of the Apollo cockpit video. Because of the similarity between mass erosion rate of soil as measured by optical extinction and rainfall rate as measured by radar reflectivity, traditional NWS radar/rainfall correlation methodology can be applied to the lunar soil case where various S(D) models are assumed corresponding to specific lunar sites. [ABSTRACT FROM AUTHOR]

Advances in robotics and additive manufacturing have become game-changing for the prospects of space industry. It has become feasible to bootstrap a self-sustaining, self-expanding industry at reasonably low cost. Simple modeling was developed to identify the main parameters of successful bootstrapping. This indicates that bootstrapping can be achieved with as little as 12 t landed on the Moon during a period of about 20 years. The equipment will be teleoperated and then transitioned to full autonomy so the industry can spread to the asteroid belt and beyond. The strategy begins with a subreplicating system and evolves toward full self-sustainability (full closure) via an in situ technology spiral. The industry grows exponentially because of the free real estate, energy, and material resources of space. The mass of industrial assets at the end of bootstrapping will be 156 t with 60 humanoid robots or as high as 40,000 t with as many as 100,000 humanoid robots if faster manufacturing is supported by launching a total of 41 t to the Moon. Within another few decades with no further investment, it can have millions of times the industrial capacity of the United States. Modeling over wide parameter ranges indicates this is reasonable, but further analysis is needed. This industry promises to revolutionize the human condition. [ABSTRACT FROM AUTHOR]

An introduction to the journal is presented in which the guest editors discuss various articles within the issue on topics including the progress made in lunar in situ resource utilization, excavation of lunar regolith, and the effects of percussion on excavation forces.

Abstract: Understanding plume impingement by retrorockets on the surface of the Moon is paramount for safe lunar outpost design in NASA’s planned return to the Moon for the Constellation Program. Visual inspection, Scanning Electron Microscopy, and surface scanned topology have been used to investigate the damage to the Lunar Surveyor III spacecraft that was caused by the Apollo 12 Lunar Module’s close proximity landing. Two parts of the Surveyor III craft returned by the Apollo 12 astronauts, Coupons 2050 and 2051, which faced the Apollo 12 landing site, show that a fine layer of lunar regolith coated the materials and was subsequently removed by the Apollo 12 Lunar Module landing rocket. The coupons were also pitted by the impact of larger soil particles with an average of 103pits/cm2. The average entry size of the pits was 83.7μm (major diameter)×74.5μm (minor diameter) and the average estimated penetration depth was 88.4μm. Pitting in the surface of the coupons correlates to removal of lunar fines and is likely a signature of lunar material imparting localized momentum/energy sufficient to cause cracking of the paint. Comparison with the lunar soil particle size distribution and the optical density of blowing soil during lunar landings indicates that the Surveyor III spacecraft was not exposed to the direct spray of the landing Lunar Module, but instead experienced only the fringes of the spray of soil. Had Surveyor III been exposed to the direct spray, the damage would have been orders of magnitude higher. [Copyright &y& Elsevier]

Abstract: A method combining photogrammetry with ballistic analysis is demonstrated to identify flying debris in a rocket launch environment. Debris traveling near the STS-124 Space Shuttle was captured on cameras viewing the launch pad within the first few seconds after launch. One particular piece of debris caught the attention of investigators studying the release of flame trench fire bricks because its high trajectory could indicate a flight risk to the Space Shuttle. Digitized images from two pad perimeter high-speed 16-mm film cameras were processed using photogrammetry software based on a multi-parameter optimization technique. Reference points in the image were found from 3D CAD models of the launch pad and from surveyed points on the pad. The three-dimensional reference points were matched to the equivalent two-dimensional camera projections by optimizing the camera model parameters using a gradient search optimization technique. Using this method of solving the triangulation problem, the xyz position of the object''s path relative to the reference point coordinate system was found for every set of synchronized images. This trajectory was then compared to a predicted trajectory while performing regression analysis on the ballistic coefficient and other parameters. This identified, with a high degree of confidence, the object''s material density and thus its probable origin within the launch pad environment. Future extensions of this methodology may make it possible to diagnose the underlying causes of debris-releasing events in near-real time, thus improving flight safety. [Copyright &y& Elsevier]

We argue that taxonomical concept development is vital for planetary science as in all branches of science, but its importance has been obscured by unique historical developments. The literature shows that the concept of planet developed by scientists during the Copernican Revolution was theory-laden and pragmatic for science. It included both primaries and satellites as planets due to their common intrinsic, geological characteristics. About two centuries later the non-scientific public had just adopted heliocentrism and was motivated to preserve elements of geocentrism including teleology and the assumptions of astrology. This motivated development of a folk concept of planet that contradicted the scientific view. The folk taxonomy was based on what an object orbits, making satellites out to be non-planets and ignoring most asteroids. Astronomers continued to keep primaries and moons classed together as planets and continued teaching that taxonomy until the 1920s. The astronomical community lost interest in planets ca. 1910 to 1955 and during that period complacently accepted the folk concept. Enough time has now elapsed so that modern astronomers forgot this history and rewrote it to claim that the folk taxonomy is the one that was created by the Copernican scientists. Starting ca. 1960 when spacecraft missions were developed to send back detailed new data, there was an explosion of publishing about planets including the satellites, leading to revival of the Copernican planet concept. We present evidence that taxonomical alignment with geological complexity is the most useful scientific taxonomy for planets. It is this complexity of both primary and secondary planets that is a key part of the chain of origins for life in the cosmos. • Vital issues were not sorted out before the rushed planet definition in 2006. • Pragmatic science since the Copernican Revolution has included moons as planets. • The concept that moons are not planets came from 1800s astrology and teleology. • Planets in any orbital state are unique as engines of complexity in the cosmos. • Defining planets this way aligns demonstrably with both historic and modern usage. [ABSTRACT FROM AUTHOR]

The erosion of lunar soil by rocket exhaust plumes is investigated experimentally. This has identified the diffusion-driven flow in the bulk of the sand as an important but previously unrecognized mechanism for erosion dynamics. It has also shown that slow regime cratering is governed by the recirculation of sand in the widening geometry of the crater. Scaling relationships and erosion mechanisms have been characterized in detail for the slow regime. The diffusion-driven flow occurs in both slow and fast regime cratering. Because diffusion-driven flow had been omitted from the lunar erosion theory and from the pressure cratering theory of the Apollo and Viking era, those theories cannot be entirely correct. [ABSTRACT FROM AUTHOR]

An integral transform relationship is developed to convert between two important probability density functions (distributions) used in the study of contact forces in granular physics. Developing this transform has now made it possible to compare and relate various theoretical approaches with one another and with the experimental data, despite the fact that one may predict the Cartesian probability density and another the force magnitude probability density. Also, the transforms identify which functional forms are relevant to describing the probability density observed in nature, and so the modified Bessel function of the second kind has been identified as the relevant form for the Cartesian probability density corresponding to exponential forms in the force magnitude distribution. Furthermore, it is shown that this transform pair supplies a mathematical framework sufficient for describing the evolution of the force magnitude distribution under shearing. Apart from the choice of several coefficients, whose evolution of values must be explained in the physics, this framework successfully reproduces the features of the distribution that are taken to be an indicator of jamming and unjamming in a granular packing. [ABSTRACT FROM AUTHOR]

Lymphangiomas of the colon are historically rare benign tumors. Only 331 cases have been reported in the world medical literature between 1931 and 2004. With widespread use of colonoscopy, however, they are being found more frequently. We report the case of a 74-year-old woman in whom a colonoscopy revealed a 3 x 4-cm submucosal lesion in the cecum that was eventually diagnosed as a lymphangioma. A CT of the abdomen showed a soft-tissue mass in the cecum and a low-density hepatic lesion. An endoscopic ultrasound of the colon showed a 3 x 4-cm hypoechoic lesion with internal septa arising from the submucosal layer of the cecum. This lesion resembled a vascular malformation; therefore a biopsy specimen was not taken. Pathologic findings of a specimen taken after a subsequent right hemicolectomy identified a submucosal lymphangioma. Published reports indicate that colonoscopy cures most lesions smaller than 2.5 cm in diameter. Resection should be reserved for larger lesions or those in patients exhibiting protein-losing enteropathy. [ABSTRACT FROM AUTHOR]

When creating asteroid regolith simulant, it is necessary to have a model of asteroid regolith to guide and to evaluate the simulant. We created a model through evaluation and synthesis of the available data sets including (1) the returned sample from Itokawa by the Hayabusa spacecraft, (2) imagery from the Hayabusa and NEAR spacecraft visiting Itokawa and Eros, respectively, (3) thermal infrared observations from asteroids, (4) the texture of meteorite regolith breccias, and (5) observations and modeling of the ejecta clouds from disrupted asteroids. Comparison of the Hayabusa returned sample with other data sets suggest the surficial material in the smooth regions of asteroids is dissimilar to the bulk regolith, probably due to removal of fines by photoionization and solar wind interaction or by preferential migration of mid-sized particles into the smooth terrain. We found deep challenges interpreting and applying the thermal infrared data so we were unable to use those observations in the model. Texture of regolith breccias do not agree with other data sets, suggesting the source regolith on Vesta was coarser than typical asteroid regolith. The observations of disrupted asteroids present a coherent picture of asteroid bulk regolith in collisional equilibrium, unlike lunar regolith, HED textures, and the Itokawa returned sample. The model we adopt consists of power laws for the bulk regolith in unspecified terrain (differential power index −3.5, representing equilibrium), and the surficial regolith in smooth terrain (differential power index −2.5, representing disequilibrium). Available data do not provide adequate constraints on maximum and minimum particle sizes for these power laws, so the model treats them as user-selectable parameters for the simulant. • A math model of asteroid regolith is developed to guide regolith simulants. • Itokawa data indicate differential index −2.5 for surface regolith fines. • Disrupted asteroids indicate differential index −3.1 for bulk regolith fines. • Infrared data are unable to inform the math model without additional progress. • HED meteorite textures indicate non-equilibrium regolith unlike disrupted asteroids. [ABSTRACT FROM AUTHOR]

This study presents a numerical investigation of rocket plumes carrying regolith particles in the context of the lunar environment (gravity and vacuum conditions). We investigated two lander masses with a single rocket hovering at 5 different low altitudes perpendicular to a flat surface. For the regolith, we considered 9 particle sizes, with diameters from 1 μ m to 1 cm. The initial condition of all particles was a null velocity at 0. 3 m above the ground. The particles started at 19 different radial positions from the centerline of the rocket jet, 1 m to 10 m. We used a DSMC method to solve the rocket plume cases, considering the combustion product molecules from the propellant N 2 O 4 +Aerozine 50. Steady-state plume flow solutions are one-way coupled with discrete particles, considering drag and weight forces. The results showed that particle angle is nearly constant for small ( d p < 100 μ m) particles varying with initial radial position and lander altitude. Particle velocity is related to particle diameter as a power-law function and a Gaussian function of the initial particle position. Lander altitude and mass modulate the magnitude of particle velocity. Using the numerical solution data, we derived a numerical correlation for particle velocity that provides insight to avoid regolith abrasive blasting into the lunar lander, surrounding structures, and orbital satellites. • Lunar rocket plumes are highly influenced by the altitude and mass of the lander. • Particles accelerated by rocket plumes may damage surrounding structures. • Trajectory angle of small particles are less sensitive to their size. • Particle damage potential can be estimated through numerical correlation. [ABSTRACT FROM AUTHOR]

The article discusses the highlights of the "2nd Workshop on Granular Materials in Lunar and Martian Exploration," held in March 2006 at the 10th Biennial ASCE Aerospace Division International Conference on Engineering, Construction and Operations in Challenging Environments. The meeting is intended to engage the science and engineering communities about core knowledge needed to build machines. The machines will be used to dig and handle the vacuum dry cohesive lunar regolith.

In situ calibration is a proposed strategy for continuous as well as initial calibration of an impact disdrometer. In previous work, a collocated tipping bucket had been utilized to provide a rainfall rate based ∼11/3 moment reference to an impact disdrometer's signal processing system for implementation of adaptive calibration. Using rainfall rate only, transformation of impulse amplitude to a drop volume based on a simple power law was used to define an error surface in the model's parameter space. By incorporating optical extinction second moment measurements with rainfall rate data, an improved in situ disdrometer calibration algorithm results due to utilization of multiple (two or more) independent moments of the drop size distribution in the error function definition. The resulting improvement in calibration performance can be quantified by detailed examination of the parameter space error surface using simulation as well as real data. [ABSTRACT FROM AUTHOR]

The supersonic gas plume of a landing rocket entrains lunar regolith, which is the layer of loose solids covering the lunar surface. This ejection is problematic due to scouring and dust impregnation of surrounding hardware, reduction in visibility for the crew, and spoofing of the landing sensors. To date, model predictions of erosion and ejection dynamics have been based largely on single-trajectory models in which the role of interparticle collisions is ignored. In the present work, the parameters affecting the erosion rate of monodisperse solids are investigated using the discrete element method (DEM). The drag and lift forces exerted by the rocket exhaust are incorporated via one-way coupling. The results demonstrate that interparticle collisions are frequent in the region immediately above the regolith surface; as many as 20% of particles are engaged in a collision at a given time. These collisions play an important role both in the erosion dynamics and in the final trajectories of particles. In addition, a direct assessment of the influence of collisions on the erosion rate is accomplished via a comparison between a "collisionless" DEM model and the original DEM model. This comparison shows that the erosion dynamics change drastically when collisions are considered and that the erosion rate is dependent on the collision parameters (coefficient of restitution and coefficient of friction). Physical explanations for these trends are provided. [ABSTRACT FROM AUTHOR]

Abstract: Future missions to the Moon may require numerous landings at the same site. Since the top few centimeters are loosely packed regolith, plume impingement from the Lander ejects the granular material at high velocities. Much work is needed to understand the physics of plume impingement during landing to protect hardware surrounding the landing sites. While mostly qualitative in nature, the Apollo Lunar Module landing videos can provide a wealth of quantitative information using modern photogrammetry techniques. The authors have used the digitized videos to quantify plume impingement effects of the landing exhaust on the lunar surface. The dust ejection angle from the plume is estimated at 1°–3°. The lofted particle density is estimated at 108–1013 particles/m3. Additionally, evidence for ejection of large 10–15cm sized objects and a dependence of ejection angle on thrust are presented. Further work is ongoing to continue quantitative analysis of the landing videos. [Copyright &y& Elsevier]

Abstract: The permeability of lunar soil simulant, JSC-1A, is measured over a range of bulk densities from 1550 to 2000kgm−3. The corresponding viscous flow permeability is 1×10−12 m2 to 6.1×10−12 m2 for this bulk density range. Implications of these values on the contamination of regolith by rockets, on barrier/enhancement to bulk flow of ice, and on cratering are discussed. Although the particle size and shape distribution of the JSC-1A are extremely wide, the permeability measurements agree surprisingly well with the Carman–Kozeny equation. The results provide evidence that the Carman–Kozeny model could be applicable to other naturally occurring soils if effective soil properties are considered. [Copyright &y& Elsevier]

Background: Ureteral stent placement to localize the ureters during operations is an invasive procedure. The aim of this study was to evaluate the feasibility of using the gamma probe to intraoperatively identify the ureters after intravenous injection of a radiopharmaceutical agent. Study Design: Ten patients undergoing elective abdominal operations were prospectively enrolled in this study. An average dose of 4.5 mCi (range 2.8 to 5.3 mCi) of technetium Tc 99m-labeled diethylenetriamine pentaacetic acid ((99m)Tc-DTPA) was administered intravenously before localization of the ureters. The gamma probe was used to localize the ureters. Correct identification of the ureters was confirmed when gentle manipulation induced a typical ureteral peristaltic pattern. Results: Gamma counts were significantly elevated in all ureters examined. Compared with background counts, gamma counts were increased over the ureter in all patients, with an average increase of 465%. The technique was modified after use in the first 3 patients and standardized for patients 4 through 10. Data from those seven patients were analyzed. Both ureters were correctly identified using the gamma probe at a mean of 15 minutes (median, 10 minutes) after a single (99m)Tc-DTPA injection (range 4 to 41 minutes). The mean background count was 80 counts per second (cps, range 50 to 130 cps). The mean ureter count was 393 cps (range 128 to 700 cps). The average percent increase of each ureter count compared with its specific background count was 465% (range 256% to 1,077%). The difference was statistically significant for all values (p < 0.001). Conclusions: This novel technique of gamma probe localization of the ureters may offer a noninvasive approach for ureteral identification. [ABSTRACT FROM AUTHOR]

• We developed two Phobos regolith simulants: PCA-1 and PGI-1. • The compositions of these represent the two leading hypotheses for Phobos's origin. • The mineralogies of PCA-1 and PGI-1 are based on remote sensing and numerical models. • We describe the methodology used to develop and characterize PCA-1 and PGI-1. • We report physical and geotechnical properties of PCA-1 and PGI-1. The Martian moon Phobos is the target of the upcoming JAXA Martian Moons eXploration (MMX) mission. There are currently no known samples of Phobos, so spacecraft hardware testing and scientific studies require Phobos regolith simulants. Here, we present two new Phobos regolith simulants: Phobos Captured Asteroid-1 (PCA-1) and Phobos Giant Impact (PGI-1). These two simulants reflect the two hypotheses for Phobos's formation, and thus the two broad possibilities for composition. This work follows previous efforts to document the development of mineralogically accurate simulants, in an effort to overcome past pitfalls with inappropriate uses of simulants. We report physical and geotechnical properties of PCA-1 and PGI-1, including their reflectance spectra, grain size distributions, abrasivity, cohesion, strength, and hardness. Our intent is for PCA-1 and PGI-1 to be open standards for Phobos simulants, and we present the simulant recipes and production methodology for use and modification by the community. [ABSTRACT FROM AUTHOR]

We have used a three-dimensional thermal and gas diffusion model to study the heated extraction of water ice from lunar regolith. Both surface heating and the insertion of heated drills were investigated for various heating power levels and expected soil ice fractions. Our calculations rely on the use of the Crank-Nicolson finite difference method for the diffusion equations. We find that the extraction of water vapor from lunar regolith requires high levels of heating power in the investigated configurations. Any heating below about 1000 ​W per m2 or per heated drill produces negligible amounts of vapor. We also find that extraction efficiencies are highly dependent on the heating configuration, as well as the initial ice fraction present in the regolith. In addition, we find that, depending on the heating configuration, significant amounts of water escape the heated volume and are lost through refreeze in colder regions. We conclude that water extraction through heating will be a power-hungry process if not optimized through additional controls (e.g. volume confinement by heated walls). In addition, the choice of a heating configuration for optimal extraction efficiency depends on the ice content of the soil. Therefore, detailed prospecting will be essential to the design of future ISRU activities on the Moon. Image 1 • Water extraction from Lunar polar regions is a crucial technique to understand. • We use 3D simulations of thermal extraction of water ice from the Lunar soil. • Heating from the surface and through inserted drills is investigated. • Water vapor recovery in various configurations is presented. [ABSTRACT FROM AUTHOR]

Results are reported from a new lunar base study with a concise architectural program: build and operate a human-tended base that produces enough oxygen and hydrogen from lunar polar ice In-Situ Resource Utilization (ISRU) for four flights per year of a reusable lander shuttling between the Lunar Gateway and the base. The study examines for the modern era issues first developed and reconciled by the Robotic Lunar Surface Operations (RLSO) study published in 1990 and resurrected at the 69th IAC in Bremen. The new study updates key assumptions for 1) resources - lunar polar ice instead of ilmenite; 2) solar power - polar lighting conditions instead of the 28-day equatorial lunation cycle; 3) transportation - use of multiple flight systems now in development and planning; 4) base site planning - a range of options near, straddling, and inside permanently shadowed regions; 5) ISRU scenarios - for harvesting ice and for constructing radiation shielding from regolith. As did the original study, RLSO2 combines US experts in mission design, space architecture, robotic surface operations, autonomy, ISRU, operations analysis, and human space mission and lunar surface experience. Unlike the original study, the new study uses contemporary tools: CAD engineering of purpose-design base elements, and integrated performance captured in a numerical operations model. This allows rapid iteration to converge system sizing, and builds a legacy analysis tool that can assess the performance benefits and impacts of any proposed system element in the context of the overall base. The paper presents an overview of the ground rules, assumptions, methodology, operations model, element designs, base site plan, and quantitative findings. These findings include the performance of various regolith and ice resource utilization schemes as a function of base location and lunar surface parameters. The paper closes with short lists of the highest priority experiments and demonstrations needed on the lunar surface to retire key planning unknowns. • It is critical to design all base elements concurrently so that they are integrated. • The base architecture must be built around quantified operations analysis. • For a large portion of time, the base must be constructed and tended to robotically. • The scale of the ISRU operations will be too large for constant human involvement. [ABSTRACT FROM AUTHOR]

A set of high‐fidelity simulated asteroid materials, or simulants, was developed based on the mineralogy of carbonaceous chondrite meteorites. Three varieties of simulant were developed based on CI1 chondrites (typified by Orgueil), CM2 chondrites (typified by Murchison), and CR2/3 chondrites (multiple samples). The simulants were designed to replicate the mineralogy and physical properties of the corresponding meteorites and anticipated asteroid surface materials as closely as is reasonably possible for bulk amounts. The simulants can be made in different physical forms ranging from larger cobbles to fine‐grained regolith. We analyzed simulant prototypes using scanning electron microscopy, X‐ray fluorescence, reflectance spectroscopy at ambient conditions and in vacuum, thermal emission spectroscopy in a simulated asteroid environment chamber, and combined thermogravimetry and evolved gas analysis. Most measured properties compare favorably to the reference meteorites and therefore to predicted volatile‐rich asteroid surface materials, including boulders, cobbles, and fine‐grained soils. However, there were also discrepancies, and mistakes were made in the original mineral formulations that will be updated in the future. The asteroid simulants are available to the community from the nonprofit Exolith Lab at UCF, and the mineral recipes are freely published for other groups to reproduce and modify as they see fit. [ABSTRACT FROM AUTHOR]

Presents summaries of reviews of books about library history. 'Museum Masters: Their Museums and Their Influences,' by Edward P. Alexander; 'Libraries in American Periodicals Before 1876,' by Larry J. Barr, H. McMullen and S. G. Leach; 'The Best Gift: A Record of the Carnegie Libraries in Ontario,' by Maragaret Beckman, S. Langmead and J. Black; 'Confessions of a Lapsed Librarian,' by R. C. Benge.

The article discusses granular materials in the solar system. These granular materials called regoliths help in better understanding of the earth and other planet's solar system histories. Regoliths are investigated for mineralogy, comminution, agglomeration, transport processes, and inventory of volatiles.

Background: Incidental appendectomy (IA) remains a controversial issue. The role of IA in the nonmanaged-care setting has not been evaluated recently. This study evaluates the cost-benefit of IA based on current third-party reimbursements and reports the incidence of pathology from routine IA during an 18-year period. Study Design: A retrospective review was performed for all patients who underwent open intestinal operations for nonappendiceal pathology by a single colon and rectal surgeon between 1988 and 2006. Patient records were reviewed for surgical indication, procedure, pathology reports, and complications. A cost-benefit analysis for IA versus laparoscopic appendectomy was performed using previously published epidemiologic data for risk of appendectomy. Results: During this period, 341 patients (mean age 62.9 years) underwent IA during open intestinal operation. Malignancy was the indication for operation in 61.6%. Pathologic findings of clinical significance in the appendix were present in 2.6% of specimens. Combined reimbursements for laparoscopic appendectomy for nonruptured and ruptured appendicitis are $8,500.95 and $15,870.37, respectively. For patients with a benign surgical indication, there was cost-benefit for IA during open operation for men younger than 55 years and women younger than 50 years of age. For patients with malignant disease, there was cost-benefit for men and women younger than 45 years of age. Conclusions: IA can be performed safely during open operation for other bowel pathology. Rate of clinically significant appendiceal pathology is low but not negligible. For patients with third-party payor status, IA can be more broadly performed during open gastrointestinal operation when no additional surgeon reimbursement is obtained. [Copyright &y& Elsevier]

Presents a guide to professional literature on reference materials. 'The Standard Periodical Directory,' 9th ed., edited by Margie Domenech; 'Computing Information Directory: A Comprehensive Guide to Computing Literature,' 3rd ed., compiled and edited by Darlene M. Hildebrandt; 'European Communities Information: Its Use and Users,' edited by Michael Hopkins.

Presents a list of books. 'Bibliography. Its History and Development,' by Bernard H. Breslauer and R. Folter; 'Fiction in Libraries,' edited by John Dixon; 'Antiquarian Bookselling in the United States: A History From the Origins to the 1940s,' by Madeleine B. Stern.

The article describes the case of a 67-year-old man with a recurring gastrointestinal stromal tumor. After undergoing a small bowel resection 6 months prior, he experienced a dull abdominal pain and developed abdominal mass. Characteristics of the mass seen through magnetic resonance imaging (MRI) are described. Exploratory laparotomy with tumor resection was done to remove tumors around the sigmoid colon, bladder and rectum. Readmission due to abdominal abscess is also discussed.