Very Large Ceramic Telescopes in Airbus Defence and Space for Space Astrophysics

Paper number

IAC-14,A7,4,3,x25431

Author

Mr. Eric Maliet, Airbus Defence and Space, France

Coauthor

Mr. Philippe Charvet, EADS Astrium Satellites, France

Coauthor

Mr. Jacques Breysse, EADS Astrium, France

Coauthor

Mr. Didier Castel, France

Coauthor

Mr. Emmanuel Sein, EADS Astrium, France

Year

2014

Abstract

The development of Silicon Carbide (SiC) ceramic technology for space telescope was started by Airbus defence and space and Boostec about 20 years ago. The first flying application was for the OSIRIS camera on board the Rosetta comet chaser.  To date, seven Airbus DS SiC-made optical payloads are satisfactorily operating in space, and more than eight payloads are currently under development. This results in the manufacturing and testing of more than 150 SiC mirrors and structural parts for space applications. 
For astronomy, the largest worldwide space telescope launched so far was developed by Airbus DS for the ESA Herschel mission, in orbit since 2009. The Herschel telescope is all SiC-made, with a primary mirror of 3.5m diameter; it operates at about 70K. SiC was the sole technology enabling to fulfil the optical quality requirements within a stringent mass constraint of 350 kg.  A study was recently conducted for ESA and JAXA related to a cryogenic infrared space observatory, SPICA, featuring as well a SiC telescope of 3.5m diameter.
For the ESA astrometry mission Gaia, two SiC telescopes are co-aligned on a toroïdal SiC optical bench of 3m diameter. The telescopes aperture is of 1.4m x 0.5m. The overall Gaia payload offers an outstanding optical quality, commensurate with the micro-arcsec final astrometry accuracy. Here again, SiC is the sole technology enabling to fulfil the mission requirements within the mass constraints stemming from a launch to L2 with Soyuz-Fregat.
In December 2012, ESA has awarded to Airbus DS the development of the EUCLID Payload Module. The EUCLID mission aims at exploring the Dark Universe with two cosmological probes: weak gravitational lensing and baryonic acoustic oscillations. The payload module features a SiC telescope of 1.2m diameter, operating in very cold condition in visible and NIR domains.
Since several years, Astrium has undertaken Research & Development on the largest monolithic space telescope that can be accommodated within an Ariane 5 fairing. The project foresees currently a 4.1m diameter main mirror, and implements active WFE control with a small deformable mirror located in an intermediate pupil. A 60nm WFE error is aimed at, for applications in the visible domain. 
Ceramic mirrors and structures have become extremely attractive for high precision & light weight opto-mechanical applications. The paper will briefly present the SiC technology and highlight its interest for space astrophysics missions as demonstrated on past and current ESA missions (Herschel, SPICA, Gaia, EUCLID).

Abstract document

IAC-14,A7,4,3,x25431.brief.pdf

Manuscript document

IAC-14,A7,4,3,x25431.pdf (🔒 authorized access only).

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