Tecnologie ottiche per lo spazio Emanuele Pace INFN – Sez. di Firenze Dip. Astronomia e Scienza dello Spazio Università di Firenze

Ottica per lo spazio a Firenze INFN Firenze Dip. Astronomia e Scienza dello Spazio – Università di Firenze INAF - Osservatorio di Arcetri INOA Galileo Avionica LAV Environmental Research Services

EUSO  = 330 ÷ 400 nm

Progettazione ottica

Esempio: HERSCHEL

Secondario adattivo: tecnologia provata al telescopio MMT (6.5m diam.) 336 attuatori 642mm diam. Primo secondario adattivo al mondo Gen. 2003 – Courtesy of CAAO Oggetto debole Sviluppato ad Arcetri. MMT e` un telescopio da 6.5m dell’Universita` dell’Arizona. Ha provato la tecnologia dei secondari adattivi in cielo. L’ottica adattiva non solo permette di aumentare la risoluzione angolare permettendo di risolvere la stella doppia (0.1 arcsec), ma concentrando la luce nell’immagine di diffrazione permette di aumentare il contrasto rispetto al fondo rendendo visibili stelle deboli (vedi oggetto debole prima invisibile).

Strutture Gruppi di progettazione ottica di sistemi ottici (INOA, DASS, INAF) Laboratorio di fabbricazione prototipi ottici (INOA) Laboratorio di progettazione e produzione di coatings e fabbricazione di specchi e filtri multistrato (LAV, DASS) Camere bianche per sviluppo rivelatori e per la produzione di ottiche strutturate (Dipartimento di Astronomia e Scienza dello Spazio) Laboratori di test e allineamento ottiche e FPA (DASS, INFN) Proposta alla Commissione Luce di Sincrotrone LNF per facility di test nell’IR-VIS-UV-softX per sistemi spaziali anche di grandi dimensioni (DASS, INFN)

Consorzio per l’ottica Centro per le ottiche spaziali INOA, Dip. Astronomia - UNIFI, INAF, LENS Attività: Progettazione ottica Ottiche ultraleggere Ottiche di grandi dimensioni Sistemi di ottica adattiva Multilayers e filtri Rivelatori LIDAR

Technological issues for large area space optics Weight a conventional 3 m  lens or mirror is too heavy (> 1000 kg) for any reasonable spacecraft Ultralightweight optics required Surface quality A sufficient optical surface quality must be guaranteed after launch and under orbital condition Active surface control possibly needed Deployment 3 m is about the maximum diameter possible with available launchers (2.5 m for Shuttle) In orbit mechanical deployment necessary

Space mirrors’ areal density

Concept of thin glass active mirrors The optical surface is coupled to stiff lightweight support structure through array of actuators, adjusted on wavefront measurements. The thin mirror is made out of thicker glass substrate while held to rigid blocking body with pitch . Mass~ 5 Kg/m2

Suitable mirror materials Needs: stiff and lightweight structure for structural integrity during launch and operations; low coefficient of thermal expansion (CTE); isotropic materials. GLASS (low stiffness, low CTE, eg. Silica-based glass) METAL (highly reflective, high stiffness, high CTE, eg. Al) CERAMIC (eg. Silicon Carbide: very high stiffness, low CTE) POLYMER (eg. Kevlar: negative CTE; high stiffness) COMPOSITE (mixing of materials, eg.fibers & matrices) FOAM (replacing web structure  lighter & stiffer struct,) A-Technology, Consorzio Technologis, Protek Foam: available in Si, SiC, Carbon. Puoi agggiungere altre note a voce, ma solo se hai tempo

In orbit deployment (I): Inflatable concepts Eg: Inflatable reflector: 25 m Ø with ~ 1 Kg/m2 - ARISE antenna Launch into orbit large piece of thin foil that has been rolled up with supporting ring structure. Assemble pieces and inflate reflective and stretchable material (membrane) with a gas. If membrane stretched beyond elastic limit permanent shape change, after pressure is released. GEO Tropospheric DIAL è un esempio di applicazione di questo oggetto

In orbit mirror deployment (II) The proposed mirror diameter requires in orbit deployment or assembling Maximum diameter possible with current launchers is  3 - 5 m Angular tolerances are not so stringent,  0.1° (0.001 ° mechanically possible) Possible deployment techniques Self deployment (like most antennas) Assembling by robots on the Shuttle Assembling by robotic arms on the ISS After assembling on ISS, the system could remain as external payload OR Several systems could be assembled this way then moved to a different orbit as free flyers (space factory concept)

A concept from NASA: OWL Deployable Schmidt camera We have developed a Schmidt system also for EUSO. FOV limited to ?? (chiedi a Vojko x sicurezza), lens just for correcting performance During deployment Packaged in the spacecraft

Advanced Lidars for Space Operation ALSO project proposal Advanced Lidars for Space Operation 2  10 m Ø A new generation of advanced LIDAR for active Earth observation (atmosphere, land, waters)  large ultralight mirrors Already proposed as Italian contribution in the ESA Roadmap for LIDAR Technology Development for Earth Observation Programme Atmospheric monitoring also needed for UHECR trace modeling  cooperation ?

Deployable antennas technologies JAXA Engineering Test Satellite ETS-VIII 40 m Purpose: orbital experiments on Large-Scale Deployable Reflectors, Application: High-Power Transponder for mobile satellite communications from geostationary orbit

KLYPVE: tecnologia dalla Russia a segmented Fresnel mirror 1.8 m , 14° FOV A reduced version (TUS, 0.6 m ) is under construction

Lightweight mirror designs Open back: material removed from back side. ~ 8 Kg/m2 Sandwich style: contiguous mirror surface- front and back - with sparsely supported center section. ~ 7 Kg/m2 Contoured back: unnecessary mass removed from back outer perimeter (the simplest form). Deformable: accommodate surface figure compensation with actuators. Open back Deformable

Ottiche adattive Adaptive telescope mirrors: Fast control of (curved) mirror shape (> 1 kHz) Small scale of correction (~ 30 mm actuator separation) Use a very thin (gass) mirror a rigid (glass) “back plate” as short term shape reference magnetic levitation of the thin mirror capacitive sensing of the gap thickness a complex real-time digital closed loop control Optical wavefront sensing for control loop Adaptive primary segment. Conceptual study for the European Large Telescope

Interesse per l’INFN Rivelazione raggi cosmici e gamma-rays Controparti ottiche e X dei GRB Telescopi multibanda Fondi di radiazione UV in atmosfera Progettazione ottica e meccanica payloads Optical GSE e facilities di test ottiche e rivelatori Problemi di contaminazione Test di radiation hardness Test ottici di payload ottici scientifici Applicazioni per luce di sincrotrone/FEL

Progetti e proposte Micro-satellite per la misura multi-wavelength del background – interesse per misure di tracce di fluorescenza in atmosfera raggi cosmici  Petrolini meteore e micro-meteoriti  meeting Firenze 28 feb.- 1 mar. Space LIDARs