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Crystallization from aqueous sodium chloride solutions as thin liquid sheets, 0.2–0.7 mm thick, with two free surfaces supported by a wire frame, thick liquid layers, 4–6 mm thick, with two free surfaces supported by metal frame, and hemispherical sessile drops, 20–32 mm diameter, supported by a flat polycarbonate surface or an initially flat gelatin film, were carried out under microgravity on the International Space Station (ISS). Different crystal morphologies resulted based on the fluid geometry: tabular hoppers, hopper cubes, circular [111]-oriented crystals, and dendrites. The addition of polyethylene glycol (PEG-3350) inhibited the hopper growth resulting in flat-faced surfaces. In sessile drops, 1–4 mm tabular hopper crystals formed on the free surface and moved to the fixed contact line at the support (polycarbonate or gelatin) self-assembling into a shell. Ring formation created by sessile drop evaporation to dryness was observed but with crystals 100 times larger than particles in terrestrially formed coffee rings. No hopper pyramids formed. By choosing solution geometries offered by microgravity, we found it was possible to selectively grow crystals of preferred morphologies. [ABSTRACT FROM AUTHOR]

We conducted experiments in space to investigate the aggregation of millimeter- and submillimeter-sized particles in microgravity, an important early step in planet formation. Particulate materials included salt (NaCl), sugar (sucrose), coffee, mica, ice, Bjurböle chondrules, ordinary and carbonaceous chondrite meteorite fragments, and acrylic and glass beads, all triply confined in clear plastic containers. Angular submillimeter particles rapidly and spontaneously formed clusters strong enough to survive turbulence in a protoplanetary nebula. Smaller particles generally aggregated more strongly and quickly than larger ones. We observed only a weak dependence of aggregation time on particle number density. We observed no strong dependence on composition. Round, smooth particles aggregated weakly or not at all. In a mixture of particle types, some phases aggregated more readily than others, creating selection effects that controlled the composition of the growing clumps. The physical process of aggregation appears to be electrostatic in nature. [ABSTRACT FROM AUTHOR]

Discusses key issues concerning waves in a large free sphere of water on the International Space Station. Series of surface waves and spherical body waves that created a number of interactions; Analysis of pertinent topics and relevant issues; Implications for studies of fluids and fluid mechanics.

A cone-shaped meniscus of electrified fluids, often called a Taylor cone, is observed in rain drops and lightning and employed in various physical instruments and experimental techniques, but the way it evolves from a rounded shape to a cone is a long-standing puzzle. Earth's gravity and microgravity measurements on the meniscus whose height is just shy of droplet ejection reveal that field-driven cusp evolution exhibits a universal self-similarity insensitive to the forcing field and scaled by the fluid surface tension and density. Our work paves the way for dynamic control of field-driven phenomena in fluids. [ABSTRACT FROM AUTHOR]

Abstract: NaCl crystals grown by the evaporation of an aqueous salt solution in microgravity on the International Space Station (ISS) were characterized and compared to salt crystals grown on earth. NaCl crystallized as thin wafers in a supersaturated film of 200–700μm thickness and 50mm diameter, or as hopper cubes in 10mm diameter supersaturated spheres. Neutron diffraction shows no change in crystal structure and in cell parameters compared to earth-grown crystals. However, the morphology can be different, frequently showing circular, disk-like shapes of single crystals with 〈111〉 perpendicular to the disks, an unusual morphology for salt crystals. In contrast to the growth on earth the lateral faces of the microgravity tabular hopper crystals are symmetrical because they are free floating during the crystallization process. Hopper cubes were produced without the need to suspend the growing crystals by an ongoing stirring. “Fleur de Sel” is shown as an example of two-dimensional growth of salt on earth and compared to the space grown crystals. It is shown that in microgravity conditions brine fluid inclusions form within the salt crystals. [Copyright &y& Elsevier]

Nighttime images taken with DSLR cameras from the International Space Station (ISS) can provide valuable information on the spatial and temporal variation of artificial nighttime lighting on Earth. In particular, this is the only source of historical and current visible multispectral data across the world (DMSP/OLS and SNPP/VIIRS-DNB data are panchromatic and multispectral in the infrared but not at visible wavelengths). The ISS images require substantial processing and proper calibration to exploit intensities and ratios from the RGB channels. Here we describe the different calibration steps, addressing in turn Decodification, Linearity correction (ISO dependent), Flat field/Vignetting, Spectral characterization of the channels, Astrometric calibration/georeferencing, Photometric calibration (stars)/Radiometric correction (settings correction - by exposure time, ISO, lens transmittance, etc) and Transmittance correction (window transmittance, atmospheric correction). We provide an example of the application of this processing method to an image of Spain. • DLSR cameras can provide accurate radiometric measurements. • ISS nighttime images using DSLR cameras can provide colour data. • Spatial resolution increased by 150–1000 times compared to popular platforms. • This opens up new possibilities for environmental studies. [ABSTRACT FROM AUTHOR]