Myriade. It’s the name of the CNES’ microsatellite platform (600/600/500mm). This base, invented in the 1990s, has already had “evolution” versions in development, but only to improve its carrying capacity and its communication with the Earth.
In an R&T study (Research and Technology), with the CNES’ initiative, SOGECLAIR aerospace has embarked on an adventure to radically revolutionise the structure of this platform, doing so with the possibilities the additive manufacturing allows.
The base structure is made out of aluminium/carbon sandwich plates. Equipments of this platform are mostly integrated from the inside.
SOGECLAIR aerospace is an aeronautic and space design office since 1986. Strong from its 25 years of experience in supporting space actors, whether for the development of satellites or launchers. SOGECLAIR aerospace has been involved in additive manufacturing since 2013 (cf ALMIA, Pylon of the future, Printsky).
New means of production (additive manufacturing) allows new possible geometries to use. These very complex geometries allow in turns the use of an unconventional design process: topological optimisation.
Starting with a simple volume, the efforts that will have to support the final object being entered in a calculation software, the latter will dig the base volume in order to keep only the useful mater. This method, that designs the part, has become a speciality of SOGECLAIR aerospace (Pylon of the future, Eole).
Since there is an almost infinite number of possible geometries in a volume, the question is by what volume to begin with?
The CNES has chosen to develop both solutions; not a problem for SOGECLAIR aerospace.
Two optimisations were made into data, with, as main load case, the vibrations caused by the launch. In both studies, around ten variations of the optimisation parameters were tested before validating the final form.
Since the calculation software’s output geometries are approximate, reconstruction is necessary. The atypical forms of topological optimisation results call for particular design tools. These modelling tools implemented by Dassault System in their flagship Catia V5 design software are well known to designers at SOGECLAIR aerospace
Interestingly, while no mass gain was expected, almost 3kg of structure was gained, or 1 to 2% of the weight of the entire satellite (30 to 70k $).
Once re-modelled, the two structures underwent a verification of most standard calculations to verify the good mechanical resistance.
Metal printers with the capacity to fabricate such large structures in aluminium do not exist yet, but this R&T has enabled the CNES to validate the possibility of designing on-demand optimised structures.
This study was presented at ECSSMET 2018 (European Conference on Spacecraft Structures, Materials and Environmental Testing). Here is the slideshow.