DRAW in the US Extremely large Telescope Program Platform

The US Extremely Large Telescope Program (US-ELTP) is a joint endeavor of the National Science Foundation’s National Optical-Infrared Astronomy Research Laboratory (NSF’s NOIRLab) and the organizations building the Thirty Meter Telescope (TMT) and the Giant Magellan Telescope (GMT). Our goals are to complete construction of both observatories and to enable all US astronomers to carry out transformational research that takes full advantage of the diverse capabilities of both GMT and TMT as well as the two-hemisphere system. NOIRLab’s portion of this initiative is a software suite called the US ELT Program Platform (UPP). The UPP will support the investigator through all phases of their observations: from proposal creation, time allocation, observation data transfer and storage, and data analysis, to publication. NOIRLab is currently preparing for a 2023 NSF Preliminary Design Review (PDR). NOIRLab used previous ground-based astronomy project experience and lessons learned to tailor our requirements management processes and help downselect a requirements management tool. To increase stakeholder communication and collaboration during the requirements generation activities, we have taken a novel approach to requirements management for astronomy projects by using the Atlassian Jira [1] add-on called “Requirements for Jira” (R4J) [2]. All facets of requirements management are conducted within the Jira environment. This approach has proven to be exemplary as Jira provides an intuitive and collaborative environment with which most of the project staff are already familiar. This paper details the motivations and results of our requirements management tool trade study and provides examples of how the requirements management processes are implemented within Jira.

<strong>11.1 Introduction</strong> Today, large-aperture modern telescope optical systems such as the ground-based Thirty Meter Telescope (TMT) and Giant Magellan Telescope (GMT) are divided into four parts: a large precision telescope radiation collector, a metrology and wavefront sensing and control (WFSC) system, the instrument that analyzes the complex wavefronts, and the detector that converts the complex wavefronts into intensity. Smaller-aperture space telescopes such as those used by the Wide-field Infrared Survey Explorer (WISE), Kepler, Stereo, and Ice, Cloud, and land Elevation Satellite (ICESat) do not require optical metrology and wavefront sensing and control because they are sufficiently small that their rigidity is obtained using mass, since the space system mass budget will accommodate it. In this chapter we expand the classical two-part astronomical optical system comprised of telescope and instrument into the much more capable (for large apertures) new three-part optical system of (1) the telescope, (2) the metrology and WFSC system, and (3) the instrument. At the heart of this new system is the two-stage optics system1 that collects, measures, and corrects the wavefront, and focuses it onto a field stop where the radiation passes into instruments that process the input complex wavefront for spectral, spatial (image), polarization, and radiometric information. In Chapters 8 and 9, we learned how scalar complex wavefronts propagate through an optical system to create an image, and we discussed the relationship between the wavefront and image quality. In Chapter 10, we learned that interferometry is a tool for analyzing the spectral (temporal) content and spatial structure of wavefronts. In this chapter, we show how wavefronts are manipulated to compensate for the following: <ul> &#x2022; telescope fabrication errors, &#x2022; the low mechanical stiffness characteristic of the new lightweight next-generation ground and space telescopes, and &#x2022; atmospheric turbulence. </ul>

The US National Science Foundation (NSF) is to assemble a panel to help it decide whether to fund the Giant Magellan Telescope (GMT) or the Thirty Meter Telescope (TMT).

Giant Magellan Telescope (GMT) is one of the largest next-generation ground telescopes whose diameter is 25.4m. It has been developed since 2003, and is expected to be finished by 2018. Korea officially joined the GMT project in 2009, and actively participates in the development. KASI (Korea Astronomy & Space Science Institute) and Korean astronomical society are planning several activities to enhance the capabilities in science research. Building a secondary mirror system is another activity Korea wants to develop. A prototype of the GMT secondary is being developed. Developing a spectrograph is another one. In this talk, I will present the plan of Korea's works for the GMT.

GumTree: Data reduction

The Primary Mirror Device Control System (M1 DCS) is one of the many Device Control Systems (DCS) included in the Giant Magellan Telescope (GMT) control system and is responsible for the overall control and operation of the GMT primary mirror segments. The primary mirror is composed of seven 8.4m diameter segments, six off-axis and one in the center. The active support system of each segment comprises 170 support actuators for the off-axis segments and 154 actuators for the center segment to control the mirror figure, and 6 hardpoints to control the six degrees of freedom of rigid body motion. The software design follows a component model-based architecture, implemented using the GMT core software frameworks. Software components of the M1 DCS are specified using a custom Domain Specific Language (DSL) and inherit all key features of the core components such as communication ports, default behaviors, telemetry, logs, alarms, faults, state machines and engineering user-interface without the need of a separate implementation. The communication between the real time software and the controlled devices is implemented by an EtherCAT Fieldbus in a ring topology. This master-slave standard protocol enables the control system to reach 100 Hz closed loop rate for active support control. This paper describes the software of the M1 DCS, the tests performed with different software and hardware simulators, and the strategy to ensure software readiness with the final optical mirror.

The Giant Magellan Telescope (GMT) is one of Extremely large telescopes, which is 25m in diameter featured with two Gregorian secondary mirrors, an adaptive secondary mirror (ASM) and a fast-steering secondary mirror (FSM). The FSM is 3.2 m in diameter and built as seven 1.1 m diameter circular segments conjugated 1:1 to the seven 8.4m segments of the primary. The guiding philosophy in the design of the FSM segment mirror is to minimize development and fabrication risks ensuring a set of secondary mirrors are available on schedule for telescope commissioning and early operations in a seeing limited mode. Each FSM segment contains a tip-tilt capability for fine co-alignment of the telescope subapertures and fast guiding to attenuate telescope wind shake and mount control jitter, thus optimizing the seeing limited performance of the telescope. The final design of the FSM mirror and support system configuration was optimized using finite element analyses and optical performance analyses. The optical surface deformations, image qualities, and structure functions for the gravity print-through cases, thermal gradient effects, and dynamic performances were evaluated. The results indicated that the GMT FSM mirror and its support system will favorably meet the optical performance goals for residual surface error and the FSM surface figure accuracy requirement defined by encircled energy (EE80) in the focal plane. The mirror cell assembly analysis indicated an excellent dynamic stiffness which will support the goal of tip-tilt operation.

The Giant Magellan Telescope (GMT) is a 24.5m diameter optical/infrared telescope. Its seven 8.4m primary mirrors give it a collecting area equivalent to a 21.4m filled aperture. The ten GMT partners are constructing the telescope at the Las Campanas Observatory in Chile with first light planned for the end of 2018. In this paper, we describe the plans for the first-generation focal plane instrumentation for the telescope. The GMTO Corporation has solicited studies for instruments capable of carrying out the broad range of objectives outlined in the GMT Science Case. Six instruments have been selected for 14 month long conceptual design studies. We briefly describe the features of these instruments and give examples of the major science questions that they can address.

We present expected performance for the Giant Magellan Telescope (GMT) adaptive optics system. Using a custom adaptive optics modeling code developed at the University of Arizona, we are able to simulate the various aspects of atmospheric turbulence, wavefront sensing, and adaptive correction for the specific geometry of the GMT AO system. This allows us to explore the design space of the GMT and determine the performance of the system for various adaptive optics modes, including Ground-Layer AO. We present results showing the effect of the segmented aperture on AO performance, and discuss strategies for sensing and correction with the GMT aperture.

Laser Tomography Adaptive Optics (LTAO) is one of adaptive optics systems planned for the Giant Magellan Telescope (GMT). End-to-end simulation tools that are able to cope with the complexity and computational burden of the AO systems to be installed on the extremely large telescopes such as GMT prove to be an integral part of the GMT LTAO system development endeavors. SL95, the Fortran 95 Simulation Library, is one of the software tools successfully used for the LTAO system end-to-end simulations. The goal of SL95 project is to provide a complete set of generic, richly parameterized mathematical models for key elements of the segmented telescope wavefront control systems including both active and adaptive optics as well as the models for atmospheric turbulence, extended light sources like Laser Guide Stars (LGS), light propagation engines and closed-loop controllers. The library is implemented as a hierarchical collection of classes capable of mutual interaction, which allows one to assemble complex wavefront control system configurations with multiple interacting control channels. In this paper we demonstrate the SL95 capabilities by building an integrated end-to-end model of the GMT LTAO system with 7 control channels: LGS tomography with Adaptive Secondary and on-instrument deformable mirrors, tip-tilt and vibration control, LGS stabilization, LGS focus control, truth sensor-based dynamic noncommon path aberration rejection, pupil position control, SLODAR-like embedded turbulence profiler. The rich parameterization of the SL95 classes allows to build detailed error budgets propagating through the system multiple errors and perturbations such as turbulence-, telescope-, telescope misalignment-, segment phasing error-, non-common path-induced aberrations, sensor noises, deformable mirror-to-sensor mis-registration, vibration, temporal errors, etc. We will present a short description of the SL95 architecture, as well as the sample GMT LTAO system simulation results.

The Giant Magellan Telescope (GMT) is a 25-meter optical/infrared extremely large telescope that is being built by an international consortium of universities and research institutions. It will be located at the Las Campanas Observatory, Chile. The GMT primary mirror consists of seven 8.4-m borosilicate honeycomb mirror segments made at the Steward Observatory Mirror Lab (SOML). Six identical off-axis segments and one on-axis segment are arranged on a single nearly-paraboloidal parent surface having an overall focal ratio of f/0.7. The fabrication, testing and verification procedures required to produce the closely-matched off-axis mirror segments were developed during the production of the first mirror. Production of the second and third off-axis segments is underway. GMT incorporates a seven-segment Gregorian adaptive secondary to implement three modes of adaptive-optics operation: natural-guide star AO, laser-tomography AO, and ground-layer AO. A wide-field corrector/ADC is available for use in seeing-limited mode over a 20-arcmin diameter field of view. Up to seven instruments can be mounted simultaneously on the telescope in a large Gregorian Instrument Rotator. Conceptual design studies were completed for six AO and seeing-limited instruments, plus a multi-object fiber feed, and a roadmap for phased deployment of the GMT instrument suite is being developed. The partner institutions have made firm commitments for approximately 45% of the funds required to build the telescope. Project Office efforts are currently focused on advancing the telescope and enclosure design in preparation for subsystem- and system-level preliminary design reviews which are scheduled to be completed in the first half of 2013.

There are various tools for real-time data acquisition and analysis of high-frequency signals. Usually, the tools for data acquisition and analysis are incompatible with each other, expensive, or require the utilization of various technologies. Designing a unique toolset for real-time data acquisition and analysis of high-frequency signals presents a large challenge, both in terms of hardware and software design. Some of the main challenges include fulfilling strict real-time performance requirements, using cost-effective hardware components, and designing a software architecture with minimal software latency for data sampling on an embedded platform and data analysis on a PC machine. This paper presents a software architecture design methodology for embedded platforms, including an RTOS and an Ethernet interface, along with the application architecture on the host side. To demonstrate the advantages of the proposed methodology, a prototype consisting of the STM32H747 microcontroller, FreeRTOS operating system, and a GUI application based on the Qt framework has been created. It has been shown that using the proposed architecture design methodology makes it possible to preserve the maximal hardware sampling rate utilizing a 100 Mbps Ethernet link. In the experiments, sampling rates up to 4.57 MSps for 10-bit resolution and real-time transfer of data over Ethernet link and visualization on host PC have been achieved with this specific MCU.

We study the application of Lyot coronagraphy to future Extremely Large Telescopes (ELTs), showing that Apodized Pupil Lyot Coronagraphs enable high-contrast imaging for exoplanet detection and characterization with ELTs. We discuss the properties of the optimal pupil apodizers for this application (generalized prolate spheroidal functions). The case of a circular aperture telescope with a central obstruction is considered in detail, and we discuss the effects of primary mirror segmentation and secondary mirror support structures as a function of the occulting mask size. In most cases where inner working distance is critical, e.g., for exoplanet detection, these additional features do not alter the solutions derived with just the central obstruction, although certain applications such as quasar-host galaxy coronagraphic observations could benefit from designs that explicitly accomodate ELT spider geometries. We illustrate coronagraphic designs for several ELT geometries including ESO/OWL, the Thirty Mirror Telescope, the Giant Magellan Telescope, and describe numerical methods for generating these designs.

This paper develops a tip-tilt motion controller of fast steering mirror (FSM) in the Giant Magellan telescope (GMT). A mathematical model of tip-tilt motion system of FSM is derived, and then based on this model, stability analysis is carried out. A heuristic adaptive controller is designed for the tip-tilt motion control with modeling error. The heuristic controller consists of two different adaptations such as initial adaptive control and adaptation at steady state errors. Through numerical simulations, the validity of the controller is illustrated. After that this paper addresses several practical issues like disturbance from wind, actuator saturation and resonance frequency from mechanical structure in implementing the controller to the actual system.

The OpenSE Cookbook is an open-sourced collection of patterns, procedures, and best practices targeted for systems engineers who seek guidance on applying model-based and executable systems engineering (MBSE) using SysML. Its content has emerged from the system level modeling effort on the European Framework Program 6 (FP6) and the Thirty Meter Telescope (TMT). The TMT MBSE approach applied the Executable Systems Engineering Method (ESEM) and the open-source Engineering Environment (OpenMBEE) to specify, analyze, and verify requirements of TMT’s Alignment and Phasing System (APS) and the Narrow Field Infrared Adaptive Optics System (NFIRAOS). In these applications, implicit dependencies are made explicit in a formal model through the use of ESEM, OpenMBEE, and SysML modeling constructs. The value proposition for applying this MBSE approach was to establish precise requirements and fine-grained traceability to system designs, and to verify key requirements beginning early in development. The integration of ESEM and the OpenMBEE tooling infrastructure (providing linked-data and web-operability) is a significant added value for the MBSE approach. The APS is responsible for the overall pre-adaptive optics wavefront quality, using starlight to measure wavefront errors and align the TMT optics. In the formally integrated and executable SysML model, simulations are performed to analyze the impact of changed requirements and verify specified constraints for various operational scenarios. The APS team used several modeling patterns to capture information such as the requirements, the operational scenarios, involved subsystems and their interaction points, the estimated or required time durations, and the mass and power consumption. Adaptive optics systems are designed to sense real-time atmospheric turbulence and correct the telescope’s optical beam to remove its effect. The system model for the adaptive optics operational modes was developed to capture sequence behaviors and operational scenarios to run Monte-Carlo simulations for verifying acquisition time, observing efficiency, and operational behavior requirements. The model is particularly useful for investigating the effect of parallelization, identifying interface issues, and re-ordering sequence acquisition tasks. A former version of the Cookbook (which is now updated to MBSE challenges, goals, and lessons learned) included modeling guidelines and conventions for all system aspects, hierarchy levels, and views, which were developed during for the Active Phasing Experiment (APE), an opto-mechatronical system technology demonstrator for the Extremely Large Telescope (ELT). The Cookbook utilizes the above mentioned system models as real-world case-studies to demonstrate and document the applications of the recipes, providing also instructional examples and addressing the available tooling support. The Cookbook is accompanied by a number of SysML models and aodel libraries which facilitate model authoring and maintenance. The Cookbook covers the different aspects of Systems Engineering such as management of Requirements, Design (behavior and structure), Interfaces, Interdisciplinary Integration, Analysis, Trade Studies, and Technical Resources. This paper presents the background, motivation, architecture, and highlights some key content of the Cookbook. For example, interface management, error budget management, requirements verification, Monte Carlo driven analysis, and timing analysis of operational scenarios. The paper discusses how the capabilities of OpenMBEE contributed significantly to the adoption of executable systems engineering.