The software package presented in this paper, still under development, was born to help analyzing the influence of the many parameters involved in the design of a large segmented mirror telescope. In summary, it is a set of tools which were added to a common framework as they were needed. Great emphasis has been made on the graphical presentation, as scientific visualization nowadays cannot be conceived without the use of a helpful 3d environment, showing the analyzed system as close to reality as possible. Use of third party software packages is limited to ANSYS, which should be available in the system only if the FEM results are needed. Among the various functionalities of the software, the next ones are worth mentioning here: automatic 3d model construction of a segmented mirror from a set of parameters, geometric ray tracing, automatic 3d model construction of a telescope structure around the defined mirrors from a set of parameters, segmented mirror human access assessment, analysis of integration tolerances, assessment of segments collision, structural deformation under gravity and thermal variation, mirror support system analysis including warping harness mechanisms, etc.
EELT AIV is the activity of assembly, integration and verification of EELT (European Extremely Large Telescope) subsystems to deliver a telescope capable of fulfilling its top-level requirements and ready to start science commissioning, leading to operations. The AIV (Assembly Integration Verification) phase covers all technical activities on Armazones and nearby Paranal Observatory from the moment the sub-systems and components are delivered or accepted on-site (from the responsible sub-system project manager). AIV includes final system tests of the completed telescope (known as “Technical Commissioning”) and the installation, alignment and telescope integration of the science instruments. The AIV phase ends with the handover of the completed telescope with installed instruments, to the start of Science Commissioning. Responsibility then passes to the Commissioning team, however the technical resources for debugging and tuning the telescope and instrument will come from a combination of the AIV team working together with the Paranal operations staff. AIV is one of the major technical challenge of E-ELT. The sheer scale and complexity of the telescope involves challenging logistics and scheduling i.e. 798 mirror segments with a staged delivery over four years, including 9,048 edge sensor and 2,394 position actuators. More than ten major sub-systems e.g. M2-3-4-5, PreFocal Station (PFS) and instruments will be integrated and tested in parallel. Finally, the technical commissioning phase will be a significant challenge. E-ELT is a highly complex active telescope system with a fully-integrated adaptive optics (AO) system. During early testing nothing will be straightforward and there will be many system-level problems to overcome. It will take a dedicated team of the “best of the best” people to troubleshoot, debug, tune, and hand over as an operational facility.
During the last 2 years ESO has operated the “M1 Test Facility”, a test stand consisting of a representative section of the E-ELT primary mirror equipped with 4 complete prototype segment subunits including sensors, actuators and control system. The purpose of the test facility is twofold: it serves to study and get familiar with component and system aspects like calibration, alignment and handling procedures and suitable control strategies on real hardware long before the primary mirror (hereafter M1) components are commissioned. Secondly, and of major benefit to the project, it offered the possibility to evaluate component and subsystem performance and interface issues in a system context in such detail, that issues could be identified early enough to feed back into the subsystem and component specifications. This considerably reduces risk and cost of the production units and allows refocusing the project team on important issues for the follow-up of the production contracts. Experiences are presented in which areas the results of the M1 Test Facility particularly helped to improve subsystem specifications and areas, where additional tests were adopted independent of the main test facility. Presented are the key experiences of the M1 Test Facility which lead to improved specifications or identified the need for additional testing outside of the M1 Test Facility.
During the advanced design phase of the European Extremely Large Telescope (E-ELT) several critical components
have been prototyped. During the last year some of them have been tested in dedicated test stands. In particular, a
representative section of the E-ELT primary mirror has been assembled with 2 active and 2 passive segments. This test
stand is equipped with complete prototype segment subunits, i.e. including support mechanisms, glass segments, edge sensors, position actuators as well as additional metrology for monitoring. The purpose is to test various procedures such as calibration, alignment and handling and to study control strategies. In addition the achievable component and subsystem performances are evaluated, and interface issues are identified. In this paper an overview of the activities related to the E-ELT M1 Test Facility will be given. Experiences and test results are presented.