Design and Development of a Relocatable Robotic Arm for Servicing On-Orbit Modular Spacecraft

The raise of orbital robotics opens a new horizon of possibilities for upcoming space missions. In the context of a global space sustainability, this paper deals with the design, development and testing of a new generation of robotic manipulator for on-orbit maintenance and servicing. This device tackles especially modular missions related to assembly and reconfiguration of modular satellites, coupled with the paradigm of standardization of spacecraft featuring standard interconnects. This robotic system benefits from an innovative multidisciplinary design for performing manipulation and relocation tasks over compatible spacecraft structures. The proposed robotic manipulator is experimentally evaluated on a representative ground demonstrator in a laboratory environment

Ideal-lens cloaks and new cloaking strategies

Previously [Courtial et al., Opt. Express 26, 17872 (2018)] we presented the theory of transformation optics (TO) with ideal lenses and demonstrated an example, an omnidirectional lens. Here we interpret this omnidirectional lens in two different parameter regimes as ideal-lens cloaks that employ different cloaking strategies: a standard “shrink cloak” in which objects appear smaller (ideally zero) and a novel “abyss cloak” in which interior physical-space positions are mapped to the exterior and thus are visible only from certain directions. We proceed to combine two nested abyss cloaks into another novel, omnidirectional, “bi-abyss cloak.” Our work significantly extends the arsenal of cloaking strategies

Photon-photon correlations in Ag+Ag collisions at √SNN = 2.55 GeV

Abstract. Photons, as penetrative probes, can deliver information about early stages of heavy-ion collisions, in contrast to hadrons, whose kinematics are determined after the freeze-out era. Given that, they provide access to quantities inaccessible for many other particle species. However, due to technical challenges of photon detection and dominance of photons from particle decays, exploiting their properties requires significant effort. Femtoscopy, a technique used to investigate the space-time characteristics of the source area, is sensitive to the emission sequence of studied particles. Hence, it can be utilized as a tool to separate photons originating from different sources. Studying femto-scopic correlations of photons can offer a new and unique perspective on source parameters before kinematic freeze-out. Using data from Ag+Ag collisions at √SNN = 2.55 GeV, collected by the HADES spectrometer, a preliminary study of photon-photon correlations was performed

Xenon bubbles formed by ion implantation in zirconium alloy films

The xenon content of a Zircaloy-4 thin film was quantified in a spatially resolved way using high angle annular dark field (HAADF) images and DualEELS, a type of electron energy loss spectroscopy that takes spectra from the high- and low-loss regions in quick succession. The xenon in the films was implanted using a tandem accelerator. The HAADF images show that the xenon had coalesced into bubbles. A semi-empirical standard was used created for the quantification using pre-existing xenon data and experimental data scaled using a Hartree Slater cross-section. This standard was used to calculate the number of atoms in the xenon bubbles and their densities and pressures were then calculated. In total, 244 were bubbles were analysed. The mean diameter, density and pressure across all the bubbles were 21.2 Å, 2355 kg/m and 5.27 GPa respectively. Most of the bubbles were gaseous xenon. The separation of the bubbles was also analysed. This work is a good demonstration of a characterisation technique for end-of-life structural materials and the technique can be easily applied to small gas bubbles in other materials

New results on light nuclei, hyperons and hypernuclei from HADES (HADES collaboration)

International audienceIn March 2019 the HADES experiment recorded 14 billion Ag+Ag collisions at √sNN = 2.55 GeV as a part of the FAIR phase-0 physics program. In this contribution, we present and investigate our capabilities to reconstruct and analyze weakly decaying strange hadrons and hypernuclei emerging from these collisions. The focus is put on measuring the mean lifetimes of these particles