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SENER Aeroespacial to build the Manipulator for the primary mirror segments of ESO’s ELT telescope

SENER Aeroespacial has signed a contract with the European Southern Observatory (ESO) to design and build the segment manipulator (SeM) for the M1 (primary mirror) of the ESO’s Extremely Large Telescope (ELT), which will be the largest optical/infrared telescope ever built.

ESO's ELT Telescope

ESO’s ELT will have a 39-meter diameter and will use a complex five-mirror optical system with the most sophisticated technology, a cutting-edge development in the field of astronomy to which SENER Aeroespacial has been contributing with its technology since 2007. In fact, SENER Aeroespacial is involved in many of the telescope’s critical opto-mechanical components (units of M1, M2, M3 and M5).

As in previous contracts, the scope of SENER Aeroespacial's work includes the design, construction and verification of the complete mechanism, which is also considered a critical system for the operation of the ELT. The primary mirror segment Manipulator (M1 SeM) is the only system that is allowed to fly over the primary mirror, which is made up of 798 mirror segments and 133 spares that are subject to constant maintenance and are continuously treated to keep them polished.

Among its main characteristics, the M1 SeM consists of a segment manipulator, which is needed to allow some of the primary mirror segments to be replaced daily. The manipulator combines a long travel distance out of the mirror, reaching 23 meters, with a short operating time of 2 and a half minutes, and a segment positioning and clamping mechanism with a wide operating range of 6 degrees of freedom, with a high degree of accuracy and repeatability.

As with the telescope's other mechanisms, the SeM must be guaranteed to work properly for the entirety of its 30-year mission in extreme conditions: the telescope will be located on the Chilean mountain of Cerro Armazones, at an elevation of over 3,000 m, and thus be subject to very low temperatures in an environment that also sees a wide range of humidity conditions and concentrations of suspended dust particles. It is also designed to withstand extreme earthquakes.

SENER Aeroespacial has been present in the field of ground-based astronomy and large scientific facilities since 2000, and has an extensive project portfolio that attests to the quality of its solutions for clients such as the European Southern Observatory (ESO). SENER Aeroespacial's work in astronomy includes optical systems, electromechanical components and systems, instrumentation systems and large mirror drive systems for both ground-based telescopes and space systems. The list of customized precision mechanisms delivered so far by SENER Aeroespacial includes the positioning systems for the M2 mirrors of the GTC, ESO’s VISTA and IRAIT telescopes, the drive system for the JPCam panoramic camera, the robotic calibration arm for ALMA, a rotator for ESO’s VLT, the drive and primary focus corrector (PFC) systems for the William Herschel Telescope, and the preliminary design of the M1 primary mirror of the EST.