Mechanical design of a floating pneumatic module for zero-gravity motion simulation

embargoed_20240906Close Proximity Operations (CPOs) are critical maneuvers between two on-orbit spacecrafts which demand an accurate control in a micro-gravity environment, hence they must be reproduced and simulated with a systematic approach. Consequently, by creating specific facilities and spacecraft simulators, laboratory tests are a crucial aspect to validate the performances of space systems for CPOs. This thesis presents the development, measurements and testing for mass-inertia properties evaluation of a floating pneumatic module, whose dimensions are representative of a 12U CubeSat system. The vehicle has been designed to perform planar low friction motion over a levelled table for docking experiments. The thesis focuses on the mechanical design of the module, which has revolved around two main requirements: (1) the possibility to accommodate a docking system for complete modularity and adaptability to different devices (e.g.: docking port); (2) the control of the position of the center of mass of the system to ensure uniform floating and pure rotations with an actuated pneumatic system. The first half illustrates a detailed overview of the assigned requirements and complete design of the module, from the early stages of development to the final one. The second half presents the several measurements and tests which have been performed to estimate the mass-inertia properties of the vehicle. The main goal has been to improve the estimation provided by the CAD model of the fully assembled system through the realization of dedicated setups to find and control the position of the center of mass and through the execution of simple rotational motions to calculate the inertia around the main axis.Close Proximity Operations (CPOs) are critical maneuvers between two on-orbit spacecrafts which demand an accurate control in a micro-gravity environment, hence they must be reproduced and simulated with a systematic approach. Consequently, by creating specific facilities and spacecraft simulators, laboratory tests are a crucial aspect to validate the performances of space systems for CPOs. This thesis presents the development, measurements and testing for mass-inertia properties evaluation of a floating pneumatic module, whose dimensions are representative of a 12U CubeSat system. The vehicle has been designed to perform planar low friction motion over a levelled table for docking experiments. The thesis focuses on the mechanical design of the module, which has revolved around two main requirements: (1) the possibility to accommodate a docking system for complete modularity and adaptability to different devices (e.g.: docking port); (2) the control of the position of the center of mass of the system to ensure uniform floating and pure rotations with an actuated pneumatic system. The first half illustrates a detailed overview of the assigned requirements and complete design of the module, from the early stages of development to the final one. The second half presents the several measurements and tests which have been performed to estimate the mass-inertia properties of the vehicle. The main goal has been to improve the estimation provided by the CAD model of the fully assembled system through the realization of dedicated setups to find and control the position of the center of mass and through the execution of simple rotational motions to calculate the inertia around the main axis

Tunable 3D luminescence patterns in glass with a femtosecond laser

International audienc

3D localization beyond diffraction limit of near-IR emission excited by resonant energy transfers from silver clusters in phosphate glasses

International audienc

Three-dimensional high spatial localization of efficient resonant energy transfer from laser-assisted precipitated silver clusters to trivalent Europium ions

We report on the 3D precipitation, using a direct laser writing approach, of highly fluorescent silver clusters in a Eu 3+-doped silvercontaining zinc phosphate glass. Micro-spectroscopy of fluorescence emission shows the ability to continuously adjust the local trichromatic coordinates in the CIE chromaticity diagram between red and white colors, thanks to the laser-deposited dose and resulting tunable combination of emissions from Eu 3+ and silver clusters. Moreover, CW and time-resolved FAST-FLIM spectroscopies showed a significant enhancement of the fluorescence emission of Eu 3+ ions while being co-located with UV-excited laser-inscribed silver clusters. These results demonstrate the ability to perform efficient resonant non-radiative energy transfer from excited silver clusters to Eu 3+ , allowing such energy transfer to be highly localized on demand thanks to laser inscription. Such results open the route to 3D printing of the rare earth ions emission in glass

Direct laser writing of visible and near infrared 3D luminescence patterns in glass

International audienceWe report the fluorescent properties of 3D localized structure with size near the diffraction limit induced by femtosecond direct laser writing (DLW) in Yb 3+ and silver-containing phosphate glass. The homogenous dispersion of the silver ions and Yb 3+ ions in the glass matrix before DLW was evidenced using photo-luminescent spectroscopy and time-resolved spectroscopy. Using high repetition rate femtosecond DLW, the inscription of 3D visible and near-infrared fluorescent patterns formed by co-localization of silver cluster and Yb 3+ ions was demonstrated. The local refractive index change associated with the formation of silver clusters is dependent on the laser irradiance. Confocal micro-luminescent spectroscopy for excitation wavelength in the visible range shows efficient emission of Yb 3+ only on DLW induced 3D fluorescent patterns. This finding demonstrated the ability to perform thanks to DLW laser a resonant efficient nonradiative energy transfer from silver clusters to Yb 3+ and allows 3D writing of near-infrared luminescence