Laboratory demonstration of a primary active mirror for space with the LATT: large aperture telescope technology

Year: 2016

Authors: Briguglio R., Biasi R., Gallieni D., Vettore C., D’Amato F., Xompero M., Arcidiacono C., Lisi F., Riccardi A., Patauner C., Lazzarini P., Tintori M., Duò F., Pucci M., Zuccaro Marchi A., Maresi L.

Autors Affiliation: INAF Osservatorio Astrofisico, Arcetri L. Enrico Fermi 5, Firenze, 50125, Italy; Microgate, Via Stradivari 4, Bolzano, 39100, Italy; ADS-International, via Roma 87, Valmadrera (LC), 23868, Italy; CNR-INO, L.go E. Fermi 6, Firenze, 50125, Italy; OHB CGS, Compagnia Generale per Lo Spazio, Italy; ESA, ESTEC, Keplerlaan 1, Noordwijk, NL-2200 AG, Netherlands

Abstract: The LATT project is an ESA contract under TRP programme to demonstrate the scalability of the technology from ground-based adaptive mirrors to space active primary mirrors. A prototype spherical mirror based on a 40 cm diameter 1 mm thin glass shell with 19 contactless, voice-coil actuators and co-located position sensors have been manufactured and integrated into a final unit with an areal density lower than 20 kg/m2. Laboratory tests demonstrated the controllability with very low power budget and the survival of the fragile glass shell exposed to launch accelerations, thanks to an electrostatic locking mechanism; such achievements pushes the technology readiness level toward 5. With this prototype, the LATT project explored the feasibility of using an active and lightweight primary for space telescopes. The concept is attractive for large segmented telescopes, with surface active control to shape and co-phase them once in flight. In this paper we will describe the findings of the technological advances and the results of the environmental and optical tests.

Conference title: SPIE Astronomical Telescopes + Instrumentation

KeyWords: Active optics; Deformable mirrors; Low-weight primary mirrors; Space telescopes; Wavefront correctors; Budget control; Glass; Locks (fasteners); Millimeter waves;Vision aids, Active Optics; Deformable mirrors; Laboratory demonstrations; Large aperture telescopes; Primary mirrors; Technological advances; Technology readiness levels; Wavefront corrector, Mirrors