A technology demonstrator for development of ultra-lightweight, large aperture, deployable telescope for space applications

Year: 2017

Authors: Zuccaro Marchi A., Gambicorti L., Simonetti F., Salinari P., Lisi F., Bursi A., Olivier M., Gallieni D.

Autors Affiliation: National Institute of Applied Optics (INOA-CNR), Largo Enrico Fermi, 6, Firenze, 50125, Italy; INAF, Arcetri Astrophysics Observatory, Largo Enrico Fermi, 5, Firenze, 50125, Italy; Carlo Gavazzi Space (CGS), via Gallarate, 15, Milano, 20151, Italy; ADS International, Via Roma, 87, Valmadrera (LC), 23868, Italy

Abstract: This work presents the latest results of new technological concepts for large aperture, lightweight telescopes using thin deployable active mirrors. The study is originally addressed to a spaceborne DIAL (Differential Absorption Lidar) at 935.5 nm for the measurement of water vapour profile in atmosphere, as an output of an ESA contract (whose preliminary results were presented at ICSO 2006). The high versatility of these concepts allows to exploit the presented technology for any project willing to consider large aperture, segmented lightweight telescopes. A possible scientific application is for Ultra High Energy Cosmic Rays detection through the fluorescence traces in atmosphere and diffused Cerenkov signals observation via a Schmidt-like spaceborne LEO telescope with large aperture, wide Field of View (FOV) and low f/#. A technology demonstrator has been manufactured and tested in order to investigate two project critical areas identified during the preliminary design: the performances of the long-stroke actuators used to implement the mirror active control and the mirror survivability to launch. In particular, this breadboard demonstrates at first that the mirror actuators are able to control with the adequate accuracy the surface shape and to recover a deployment error with their long stroke; secondly, the mirror survivability has been demonstrated using an electrostatic locking between mirror and backplane able to withstand without failure a vibration test representative of the launch environment.

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More Information: The authors are grateful to the Europe Space Agency for the opportunity offered to develop this research under the contract 18944/05/NL/CP – Advanced LIDAR Concept. The authors are grateful to ADS International SRL for pictures of the actuator and to Roberto Biasi of MICROGATE S.r.l. for his important contributions.
KeyWords: Actuators; Cosmic rays; Cosmology; Electrostatic actuators; Locks (fasteners); Mirrors; Optical radar; Space applications; Space telescopes; Water absorption, Active Optics; Deployable; Large aperture; Light weight optics; Schmidt, Optical testing