Spacecraft structures, materials and mechanisms
The spacecraft structure is the physical platform that supports and integrates subsystems and payload and as such it is of fundamental importance for any spacecraft.
The use of the most appropriate structural materials is a key part of the structural design process, and similarly the implementation of mechanisms to enable specific functions, ranging from attitude control to deployment of various elements, is interlinked with the spacecraft structural design. The Spacecraft Structures, Materials and Mechanisms group is led by Prof. Guglielmo S Aglietti.
Spacecraft microvibrations and stable structures
Microvibration produced by the functioning of on board equipment (e.g. reaction wheel assemblies, cryocoolers, pointing mechanism etc.), and propagating through the spacecraft structure can seriously degrade the performance of accurately targeted payloads (e.g. high resolution cameras or telescopes, interferometers etc.). Our work is in the modelling and control of microvibrations and in particular we carry out theoretical modelling of transmission (and control) supported by experimental verification activities and on-orbit validation.
Related to this work is our activity on ultra-stabile structures where we are investigating procedures to increase the stability of CFRP structures exposed to harsh environments.
Multifunctional structures are a particular type of structure that integrate other functions such as electrical power storage, in addition to their typical mechanical load bearing function. The overall aim is to achieve fully integrated systems where subsystems perform multiple functions in order to optimize the performance of the system. Our work has pioneereed the implementation of this concept in spacecraft structures, with particular emphasis on power structures, where different types of power storage elements have been included in structural panels.
Electronics for space applications
We investigate the mechanical design of electronic hardware, in particular enclosures for printed circuit boards, with emphasis on modelling their capability to withstand harsh vibration environments (i.e. during launch). We carried out work on modelling of the response of packages and appropriate failure criteria to assess the suitability of the design and allow further optimization. With SSTL we developed the first mechanical system that has allowed standard computer HDDs to be used on board satellites. The hardware was successfully flown on the SSTL satellite Beijing-1 launched on 27 October 2005 and has functioned correctly for the whole duration of the mission.
Validation of FEM
The validation of finite element models (FEM) is particularly important in the space industry because the loads experienced by a satellite during launch can only be accurately predicted by analysing the FEM of the satellite coupled with that of the launch vehicle (LV). Our work aims at ensuring that, beside compliance with launch agencies specifications to ensure good correlation between FEM and physical tests results (modal assurance criteria, cross orthogonality checks etc.) the FEM is actually able to simulate/predict the relevant behaviours of the physical spacecraft structure.