During the launching phase, satellites are undoubtedly faced to severe mechanical environment, which appears to be one of the most critical issues to cope with. Various solutions can be investigated to protect the onboard equipments during these critical phases. Actually, theses vibratory damages can be reduced at the same time by optimising the architecture of the satellite but also by local actions aiming more on the propagation of the vibrations and thus limiting the transmission of the vibrations through the whole equipment.
The latter solution also called “passive solution” is developed by SMAC under the CNES contract to protect along all six degree of freedom the small reaction wheel, chosen for the MYRIADE microsatellite family, from random vibrations and shocks. This original solution consists in uncoupling the reaction wheel from the satellite structure by an isolator system made out of a high damping viscoelastic material: the SMACTANE®.
Technical trade-off and design issue, that has led to select the final flight configuration, will be discussed in parallel with the design constraints in term of: – mass and size, due to the lack of space onboard MYRIADE platform, – and transfer function performances, addressing low cut-off frequency and quality-factor limitation at cut-off frequency.
In particular, the solution implemented in order to minimize coupling phenomenon between axis will be particularly described.
Main features of the flight models and the qualification tests results will be given.
damping viscoelastic materials have some disadvantages, like their non-linear behaviour depending on the mechanical levels applied and their poor thermal and electric conductivity.
So, to conclude, we try to show how new ways seem to be promising and keep all interest in using viscoelastic materials in space applications.
On the one hand, the way to specify the damping performances and to characterize them will be in particular discussed.
On the other hand, an alternative solution to the thermal braids here selected is currently investigated under CNES R&T funding to avoid additional parts and also parasitic stiffness in parallel of the elastomer mounts. The first tests results of a new kind of elastomeric material developed will also be addressed.
During the launching phase, satellites and their equipments undergo complex and critical vibratory environment which can damage definitively the onboard equipments. Several solutions can be considered to protect the onboard equipments during these critical phases. Vibratory damages can be reduced by optimising the satellite architecture but in the same time, local actions can limit the transmission and propagation of the vibrations to the onboard equipment.
The latter solution also called “passive solution” is developed by SMAC under a CNES contract to protect the reaction wheel chosen for the “MYRIADE” microsatellite family from random vibrations and shocks during the launching phase. The original solution consists in an insulating system based on damping elastomeric mounts reducing the transmitted levels between the satellite structure and the reaction wheel. Damping properties and reduced volume are the main ways to carry out this original development.
After presenting the reaction wheel characteristics and damping objectives, this paper will focus on the chosen design and material using which enables to obtain the performances established during the qualification step.
The reaction wheel to protect is the small reaction wheel chosen for the MYRIADE microsatellite family and commercialised by TELDIX. In this paragraph main reaction wheel characteristics are presented to understand the development of the damping isolator.