Title
Meeting highest performance requirements for lowest price and mass for the M1 segment support unit for E-ELT
Author
TNO Industrie en Techniek
Nijenhuis, J.R.
Hamelinck, R.F.M.M.
Braam, B.C.
Cayrel, M.
Publication year
2010
Abstract
The largest optical telescope in the world will be the E-ELT. Its primary mirror will be 42m in diameter. This mirror will consist of 984 hexagonal segments that are all individually supported. Each mirror will be controlled in six DOF while local shaping of the segments is provided by so called warping harnesses. These will correct for focus, astigmatism and trefoil. Hence a mirror with an extreme diameter to thickness ratio of almost 30 is obtained. Its support structure must guarantee a maximum surface form error of 30 nm rms independent of the segment attitude. Furthermore its stiffness to mass ratio must allow natural frequencies of 50Hz or higher to obtain sufficient bandwidth for the actuators that control the piston and tip/tilt of the segment. Designing such structure is a challenge that has been successfully completed. Three prototypes have been built and are about to be delivered to ESO. This paper discusses the main performance requirements and how they could be transferred into an elegant structure design. Furthermore an overview will be given on the main performance parameters in order to see whether the present design can be further optimized. © 2010 SPIE.
Subject
ELT
M1 support structure
Opto-mechanics
Static determined
ELT
Form errors
Hexagonal segments
Lowest price
Opto-mechanics
Performance parameters
Performance requirements
Primary mirrors
Six-DOF
Static determined
Stiffness-to-mass ratio
Structure design
Support structures
Thickness ratio
Airborne telescopes
Ground supports
Mechanics
Optical telescopes
Mirrors
Space
Information Society
Mechatronics, Mechanics & Materials Physics & Electronics
OM - Opto-Mechatronics SSE - Space Systems Engineering
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TNO identifier
425157
ISBN
9780819482235
ISSN
0277-786X
Source
Ground-Based and Airborne Telescopes III, 27 June - 2 July 2010, San Diego, CA, USA, 7733 (7733)
Series
Proceedings of SPIE - The International Society for Optical Engineering
Document type
conference paper