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The Japanese MMX sample return mission to Phobos by JAXA will carry a rover developed by CNES and DLR that will be deployed on Phobos to perform in situ analysis of the Martian moon's surface properties. Past images of the surface of Phobos show that it is covered by a layer of regolith. However, the mechanical and compositional properties of this regolith are poorly constrained. In particular, from current remote images, very little is known regarding the particle sizes, their chemical composition, the packing density of the regolith as well as other parameters such as friction and cohesion that influence surface dynamics. Understanding the properties and dynamics of the regolith in the low-gravity environment of Phobos is important to trace back its history and surface evolution. Moreover, this information is also important to support the interpretation of data obtained by instruments onboard the main MMX spacecraft, and to minimize the risks involved in the spacecraft sampling operations. The instruments onboard the Rover are a Raman spectrometer (RAX), an infrared radiometer (miniRad), two forward-looking cameras for navigation and science purposes (NavCams), and two cameras observing the interactions of regolith and the rover wheels (WheelCams). The Rover will be deployed before the MMX spacecraft samples Phobos' surface and will be the first rover to drive on the surface of a Martian moon and in a very low gravity environment. [ABSTRACT FROM AUTHOR]

Xylan is a highly available polysaccharide in the plant kingdom and is therefore a valuable resource for novel materials from renewable resources. Hydroxyalkylation is one of the most common reactions to derivatize biopolymers by altering hydroxyl groups. State of the art procedures incorporate epoxides, which are toxic, carcinogenic and highly explosive. In this study, hydroxyalkylation with propylene carbonate (PC) was used as green approach to synthesize xylan derivatives. Reaction pathways under homogeneous conditions, in dimethyl sulfoxide (DMSO), and heterogeneous conditions, without solvent, are compared. Analysis using liquid state and high resolution magic angle spinning (HRMAS) NMR, a novel approach for insoluble but swellable polysaccharide derivatives, as well as FTIR spectroscopy, hydrolysis in combination with borate anion exchange chromatography, and rheology showed significant differences regarding the structure of the products. While the degree of substitution (DS) is similar under both conditions, side chains are significantly longer under heterogeneous conditions, implying a higher rate of homopolymerization. This leads to a non-complete decarboxylation. The higher sterical hindrance imposed by longer side chains therefore leads to a higher tendency of xylose monosaccharides being derivatized at only one native hydroxyl group, while under homogeneous conditions a higher tendency towards double substitution can be observed. Rheology showed a shear thinning behaviour as well as an increase in viscosity with DS for samples from homogeneous synthesis. Products from solvent-free approach were analyzed in swollen state. They showed gel-like behaviour, whose elasticity increases with increasing DS as a result of side chain entanglement. [ABSTRACT FROM AUTHOR]