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The latest high-performance telescopes for deep space observation employ verylarge primary mirrors that are made of smaller segments, like the JWST whichemploys monolithic beryllium hexagonal segments. A very promising developmentstage of these systems is to make them active and to operate on theirreflective surfaces to change their shape and compensate for aberrations aswell as to perform a very precise alignment. This is possible by employing areference body that stores actuators to modify the shape of the shell, like inthe SPLATT project where voice coil actuators are used. However, the lack ofphysical contact between the main body and shell places, along with the manyadvantages related to the physical decoupling of the two bodies, some concernsrelated to the retaining of the shell under all the possible accelerationconditions affecting the system during the mission lifetime. This paper aims tostudy the acceleration environment affecting the spacecraft during its lifetimeand to use it as a baseline for operational requirements of a retaining systemfor the shells. Any solution is selected in this paper to leave completefreedom for the development of a constraining system, just some arequalitatively discussed.

Lateral constraint for thin glass shell: analysis of the requirements and conceptual design for a segmented active mirror