Granular Materials and the Risks They Pose for Success on the Moon and Mars

Working with soil, sand, powders, ores, cement and sintered bricks, excavating, grading construction sites, driving off-road, transporting granules in chutes and pipes, sifting gravel, separating solids from gases, and using hoppers are so routine that it seems straightforward to do it on the Moon and Mars as we do it on Earth. This paper brings to the fore how little these processes are understood and the millennia-long trial-and-error practices that lead to today's massive over-design, high failure rate, and extensive incremental scaling up of industrial processes because of the inadequate predictive tools for design. We present a number of pragmatic scenarios where granular materials play a role, the risks involved, and what understanding is needed to greatly reduce the risks

Data from: Nikuradse and Shields: turbulent roughness controls shear stress at incipient sediment transport

This collection contains supporting information for M. Y. Louge, A. Valance, Nikuradse and Shields: turbulent roughness controls shear stress at incipient sediment transport, J. Geophys. Res. Earth Surface (2024). The Nikuradse (1933) data of Darcy friction for turbulent flow in roughened pipe and shear stress measurements at incipient transport from Shields (1936) and later authors indicate that the threshold dimensionless shear stress Sh for entrainment of cohesionless sediment of diameter d is proportional to the 'turbulent roughness' z0 in the core of the boundary layer on a flat surface, Sh = (2.28+/-0.18) (rho/rhos)^(1/3) z0/d, where rhos and rho are material densities of solid and fluid in the range 2.6 < (rhos/rho) < 1.3 10^6. This expression is valid when the boundary layer is fully turbulent for Reynolds numbers 0.63 < Re* < 1100 based on shear velocity and d. Such insight suggests that turbulent roughness governs the entrainment of particles from a planar sediment bed, whether Newtonian liquid or gas continua are involved. It also provides a new interpretation of the ratio z0/d at incipient transport, not as a geometrical aspect ratio, but rather as friction that the turbulent flow must exert to lift sediment from the surface.This research was supported in part by the National Science Foundation under Grant No. NSF PHY-1748958, which allowed the authors to attend a program at the Kavli Institute for Theoretical Physics, and by the ISblue project, Interdisciplinary Graduate School for the Blue Planet (ANR-17-EURE-0015) that fostered related discussions on dune modeling. A.V. acknowledges the support of the French Research National Agency through project ANR-21-CE30-0066

ISS Microgravity Experiments: Data Analysis

Please cite as: Sahoo, Shilpa, Michel Y. Louge, and Oliver Desjardines (2021). ISS Microgravity Experiments: Data Analysis [Dataset]. Cornell University eCommons Repository. https://doi.org/10.7298/kfej-df78.To study imbibition on Earth, time and distance must be shrunk to mitigate gravity-induced distortion. These small scales make it impossible to observe the inertial and pinning processes in detail. Therefore, the microgravity on the International Space Station (ISS) was exploited to study the imbibition of water into a network of hydrophilic cylindrical capillaries on time and length scales long enough to observe details hitherto inaccessible under Earth gravity. To investigate the role of contact pinning, a text matrix needed to be produced which consisted nine kinds of porous capillary plates made of gold-coated brass treated with Self-Assembled Monolayers (SAM) that fixed advancing and receding contact angles to known values. In the ISS, astronaut Luca Parmitano slowly extruded water spheres until they touched any of nine capillary plates. The 12mm diameter droplets were large enough for high-speed GX1050C video cameras on top and side to visualize details near individual capillaries, and long enough to observe dynamics of the entire imbibition process. The high-speed videos of spreading and imbibition on the capillary plates were obtained and analyzed. The data analysis is presented here. This contains .mp4translations of the original NASA-generated .avi videos in https://doi.org/10.7298/MKBW-KF79; spreadsheets and Matlab programs for data reduction and the PhD thesis of Shilpa Sahoo explaining the data and their analysis.National Science Foundation Grant CBET 1637531 and User Agreement UA‐2017‐228 from the Center for the Advancement of Science in Space under NASA Cooperative Agreement NNH11CD70A

ISS Microgravity Experiments: Raw Data from NASA

Please cite as: Sahoo, Shilpa, Louge, Michel Y. , & Desjardins, Oliver. (2021). ISS Microgravity Experiments: Raw Data from NASA [Dataset]. Cornell University eCommons Repository. https://doi.org/10.7298/MKBW-KF79To study imbibition on Earth, time and distance must be shrunk to mitigate gravity-induced distortion. These small scales make it impossible to observe the inertial and pinning processes in detail. Therefore, the microgravity on the International Space Station (ISS) was exploited to study the imbibition of water into a network of hydrophilic cylindrical capillaries on time and length scales long enough to observe details hitherto inaccessible under Earth gravity. To investigate the role of contact pinning, a text matrix was produced which consisted nine kinds of porous capillary plates made of gold-coated brass treated with Self-Assembled Monolayers (SAM) that fixed advancing and receding contact angles to known values. In the ISS, astronaut Luca Parmitano slowly extruded water spheres until they touched any of nine capillary plates. The 12mm diameter droplets were large enough for high-speed GX1050C video cameras on top and side to visualize details near individual capillaries, and long enough to observe dynamics of the entire imbibition process. The high-speed videos of spreading and imbibition on the capillary plates were obtained and are presented here.National Science Foundation Grant CBET 1637531 and User Agreement UA‐2017‐228 from the Center for the Advancement of Science in Space under NASA Cooperative Agreement NNH11CD70

ISS Microgravity Experiments: Preparation Work

To study imbibition on Earth, time and distance must be shrunk to mitigate gravity-induced distortion. These small scales make it impossible to observe the inertial and pinning processes in detail. Therefore, the microgravity on the International Space Station (ISS) was exploited to study the imbibition of water into a network of hydrophilic cylindrical capillaries on time and length scales long enough to observe details hitherto inaccessible under Earth gravity. To investigate the role of contact pinning, a text matrix needed to be produced which consisted nine kinds of porous capillary plates made of gold-coated brass treated with Self-Assembled Monolayers (SAM) that fixed advancing and receding contact angles to known values. On Earth, flat, 25% surface fraction and 50% surface fraction brass plates were designed and manufactured. The CAD files of these are presented here. Then they were electrolessly gold-deposited with the help of the group of Prof. Sadik Omowunmi at the University of Binghamton (now at the New Jersey Institute of Technology). The SEM images of these brass and gold-plated samples are also shown here. Then they were coated with SAMs, the MSDS of each chemical are presented here. Additionally, the contact angle measured by goniometry on these plates after SAM coating are exhibited here. Finally, the excerpts of the original NSF proposal for this project; crew procedures for set up, execution and stowage of the ISS experiment and PI science requirements forming the basis of the design by Zin-Technologies has also been presented here.This work was supported by: National Science Foundation Grant CBET 1637531 and User Agreement UA‐2017‐228 from the Center for the Advancement of Science in Space under NASA Cooperative Agreement NNH11CD70A

Data from: Evolution of turbulent boundary conditions on the surface of large barchan dunes: anomalies in aerodynamic roughness and shear velocity, aeolian thresholds and the role of dune skewness

This collection contains supporting information for M. Y. Louge, A. Valance, J. Fang, S. Harnett, F. Porte-Agel, P. Chasle, Evolution of turbulent boundary conditions on the surface of large barchan dunes: anomalies in aerodynamic roughness and shear velocity, aeolian thresholds and the role of dune skewness, J. Geophys. Res. Earth Surface (2023). It consists of one .xlsx Excel workbook and six .csv worksheets, with contents summarized in the readme.txt file. Wind friction is the engine that erodes sand dunes, relentlessly pushing them over roads, houses and infrastructure. Our records of wind speed on crescent-shaped mobile dunes challenge conventional understanding of this process. Using field measurements and models, we show that the highest friction occurs where the gentle upward dune surface abruptly gives way to a steeper avalanching downward slope. Our data also reveals that the `aerodynamic roughness', a measure of wind friction on sand, contradicts existing models based on historical data for turbulent pipe flow. Because numerical simulations are used to predict flow over landforms that are inaccessible to detailed measurements, we validate them against data on a large dune. Our observations imply that, to achieve greater fidelity, simulations should subdivide the fluid neighborhood of the dune more finely, and revisit how they treat aerodynamic friction on its surface. Although our work involved large desert dunes, we expect these suggestions to apply more broadly to atmospheric, fluvial or submarine landforms that are surrounded by rougher terrain or that feature sudden changes in slope.This collection was made possible by the support of NPRP grants 09-546-2-206 and 6-059-2-023 from the Qatar National Research Fund, and by a Qatar Foundation Research Excellence Award. It was supported in part by the National Science Foundation under Grant No. NSF PHY-1748958, which allowed MYL and AV to attend a program at the Kavli Institute for Theoretical Physics, and by the ISblue project, Interdisciplinary Graduate School for the Blue Planet (ANR-17-EURE-0015) that fostered related discussions on dune modeling. AV acknowledges the support of the French Research National Agency through project ANR-21-CE30-0066

Microgravity spreading of water spheres on hydrophobic capillary plates

We create nearly perfect centimetric spheres of water by splitting a cavity consisting of two metal hemispheres coated with a hydrophobic paint and under-filled with liquid, while releasing the apparatus in free-fall. A high-speed camera captures how water spread on hydrophobic aluminum and polycarbonate plates perforated with cylindrical capillaries. We compare observations at the ZARM drop tower in Bremen with Lattice-Boltzmann numerical simulations of Frank, Perré and Li for the inertial phase of imbibition