On June 9th, 2014, the design/build contract for the Large Synoptic Survey Telescope (LSST) Mount Assembly (TMA) system was awarded to GHESA Ingeniería y Tecnología, S.A. and Asturfeito, S.A. This paper describes the current status of the fabrication, assembly, and verification, along with the logistic plans to ship the mount and equipment to Cerro Pachón in Chile. The design of the mount successfully passed the final design review on January 29, 2016, and is currently under full-scale construction at Asturfeito’s factory in Avilés, Spain.
A detailed description the critical design, fabrication challenges, and the state of testing is presented for the following subsystems:
Azimuth track assembly: The 16-m diameter azimuth track which was fabricated in four large sectors provides the mounting surfaces for the axial and radial hydrostatic bearings. This high precision surface has been machined to high flatness and circularity to meet the high pointing repeatability requirements.
Azimuth structure: The azimuth structure consists of 20 large weldments. These large heat-treated weldments were designed to minimize pointing hysteresis and yet be small enough to be transported by truck.
Elevation structure: The elevation structure consists of a large central ring structure that supports both the M1M3 mirror cell and the optical support for the M2 and camera.
Azimuth mechanicals: The azimuth structure uses 16 linear motors designed and fabricated by Phase Motion Control. All motors, motion control, and capacitor banks have been delivered to the factory and are being prepared for installation
Hydrostatic bearings: All hydrostatic bearings have been designed and fabricated by SKF. The oil supply system was designed by SKF and HYDX hydraulic solutions. The azimuth bearings have been installed and tested using the azimuth platform.
Mount control system hardware and software: The hardware, engineering interface and the software that connects to the telescope control system was designed, assembled, and tested by iK4 Tekniker. This system has been tested using the camera cable wrap and the M1M3 mirror covers at Tekniker. The system is now being installed the factory to begin testing on the assembled mount.
Camera cable wrap: The top end of the telescope requires a complex cable wrap for all of the cameras services and utilities. This wrap successfully passed verification testing and is now installed on the telescope top end.
M1M3 mirror cover: This unique four-fan design was developed and tested at ik4 Tekniker. After verification at Tekniker it was shipped to the factory and is now assembled on the azimuth ring assembly.
Utility distribution: Fluid distribution system includes a large network of coolants, refrigerants, air, fibers optics, and data communication lines. The unique challenges to routing throughout the telescope all of these services required coordinated design and implementation and four cable wraps. The azimuth cable wrap is a motorized drape design designed by Empresarios Agrupados and Tekniker. The two elevation drapes were designed by Empresarios Agrupados and Kabbleschlepp.
An overview of the logistics required for shipping, ground transportation, and cranes will be described.
Proc. SPIE. 9911, Modeling, Systems Engineering, and Project Management for Astronomy VII
KEYWORDS: Actuators, Telescopes, Mirrors, 3D modeling, Space telescopes, Finite element methods, Computer aided design, Large Synoptic Survey Telescope, Large Synoptic Survey Telescope, Systems modeling, Solid modeling
During this early stage of construction of the Large Synoptic Survey Telescope (LSST), modeling has become a crucial system engineering process to ensure that the final detailed design of all the sub-systems that compose the telescope meet requirements and interfaces. Modeling includes multiple tools and types of analyses that are performed to address specific technical issues. Three-dimensional (3D) Computeraided Design (CAD) modeling has become central for controlling interfaces between subsystems and identifying potential interferences. The LSST Telescope dynamic requirements are challenging because of the nature of the LSST survey which requires a high cadence of rapid slews and short settling times. The combination of finite element methods (FEM), coupled with control system dynamic analysis, provides a method to validate these specifications. An overview of these modeling activities is reported in this paper including specific cases that illustrate its impact.
This paper describes the status and details of the large synoptic survey telescope1,2,3 mount assembly (TMA). On June 9th, 2014 the contract for the design and build of the large synoptic survey telescope mount assembly (TMA) was awarded to GHESA Ingeniería y Tecnología, S.A. and Asturfeito, S.A. The design successfully passed the preliminary design review on October 2, 2015 and the final design review January 29, 2016. This paper describes the detailed design by subsystem, analytical model results, preparations being taken to complete the fabrication, and the transportation and installation plans to install the mount on Cerro Pachón in Chile. This large project is the culmination of work by many people and the authors would like to thank everyone that has contributed to the success of this project.