Journal of Astronomical Telescopes Instruments and Systems最新文献

{"title":"Lessons learned from systems engineering on the James Webb Space Telescope","authors":"Michael Menzel, Keith Parrish, Lee Feinberg, Paul Geithner, Julie Van Campen, Michael McElwain, Sandra Irish","doi":"10.1117/1.jatis.10.1.011208","DOIUrl":"https://doi.org/10.1117/1.jatis.10.1.011208","url":null,"abstract":"The James Webb Space Telescope is NASA’s flagship mission and successor to the highly successful Hubble Space Telescope. It is an infrared observatory featuring a cryogenic 6.6 m aperture, deployable optical telescope element with a payload of four science instruments assembled into an integrated science instrument module that provide imagery and spectroscopy in the near infrared band between 0.6 and 5 μm and in the mid-infrared band between 5 and 28 μm. JWST was successfully launched on December 25, 2021, aboard an Ariane 5 launch vehicle. All 50 major deployments were successfully completed by January 8, 2022. The observatory performed all mid-course correction maneuvers and achieved its operational mission orbit around the Sun-Earth second Lagrange Point. All commissioning and calibration activities have been completed and JWST has begun its science mission. Its present performance meets or out-performs all requirements. Launching over 20 years after its mission concept review, the JWST Observatory is a first and only of its kind of facility. This program faced many unique challenges that were not only technical in nature but also organizational and managerial. We describe the challenges faced by the JWST systems engineering team, the way the team addressed them, and make recommendations for focus areas of future flagship missions, which will likely face similar challenges. It will not explicitly address the cost challenges of the mission. We first describe the mission and its over-arching challenges. We then describe the tailoring of systems engineering processes and methods used to address these challenges and effectiveness. The events, tasks, issues, and their resolutions and the resulting specific lessons learned from the project are discussed with the over-arching recommendations for future flagship missions that derive from these lessons.","PeriodicalId":54342,"journal":{"name":"Journal of Astronomical Telescopes Instruments and Systems","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139750526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spectral characterization of the Grism and Prism slitless spectrometers for the Nancy Grace Roman Space Telescope","authors":"Evan Bray, Mateo Batkis, Victor J. Chambers, Margaret Dominguez, Bente Eegholm, Guangjun Gao, Qian Gong, Wesley Halliday, Elias Howe, Jeffrey Kruk, Eliot Malumuth, Sangeeta Malhotra, Catherine Marx, James Rhoads, Maxime Rizzo, Joshua E. Schlieder, Laurie Seide, Eric R. Switzer, Jay Voris","doi":"10.1117/1.jatis.10.1.014003","DOIUrl":"https://doi.org/10.1117/1.jatis.10.1.014003","url":null,"abstract":"The Roman Space Telescope Grism and Prism assemblies will allow the wide-field instrument (WFI) to perform slitless, multi-object spectroscopy across the complete field of view. These optical elements play a critical role in the High Latitude Wide Area and High Latitude Time Domain Surveys, which are designed to produce robust spectroscopic redshifts for millions of objects over the mission lifetime. To facilitate the characterization of these assemblies, a dedicated test bed was designed and utilized to perform a wide variety of spectroscopic measurements over the full range of operational wavelengths and field angles. Characterized features include, but are not limited to dispersion magnitude, dispersion clocking, encircled energy, total throughput, and bandpass edges. We present the results of this experimental campaign in which the Grism and Prism assemblies met or exceeded many of their design requirements and discuss measurement limitations.","PeriodicalId":54342,"journal":{"name":"Journal of Astronomical Telescopes Instruments and Systems","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139750415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Benefits of adding radial phase dimples on scalar coronagraph phase masks","authors":"Niyati Desai, Dimitri Mawet, Eugene Serabyn, Garreth Ruane, Arielle Bertrou-Cantou, Jorge Llop-Sayson, A. J. Eldorado Riggs","doi":"10.1117/1.jatis.10.1.015001","DOIUrl":"https://doi.org/10.1117/1.jatis.10.1.015001","url":null,"abstract":"Current scalar coronagraph focal plane mask designs are performance-limited by chromaticity. We investigate the effects of adding central Roddier and dual zone phase dimples to scalar masks to improve broadband performance by suppressing the chromatic stellar leakage. We present hybrid designs with radial phase dimples integrated with the sawtooth vortex, wrapped vortex, and cosine phase mask. We show that, using these dimples, it is possible to substantially improve the broadband contrast performance of scalar phase masks. We also show that, although adding a phase dimple does not increase the sensitivity to low-order aberrations, suppressing the central leakage of scalar vortex coronagraphs does not restore the aberration sensitivities to their notional state.","PeriodicalId":54342,"journal":{"name":"Journal of Astronomical Telescopes Instruments and Systems","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139750733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Laboratory experiments of model-based reinforcement learning for adaptive optics control","authors":"Jalo Nousiainen, Byron Engler, Markus Kasper, Chang Rajani, Tapio Helin, Cédric T. Heritier, Sascha P. Quanz, Adrian M. Glauser","doi":"10.1117/1.jatis.10.1.019001","DOIUrl":"https://doi.org/10.1117/1.jatis.10.1.019001","url":null,"abstract":"Direct imaging of Earth-like exoplanets is one of the most prominent scientific drivers of the next generation of ground-based telescopes. Typically, Earth-like exoplanets are located at small angular separations from their host stars, making their detection difficult. Consequently, the adaptive optics (AO) system’s control algorithm must be carefully designed to distinguish the exoplanet from the residual light produced by the host star. A promising avenue of research to improve AO control builds on data-driven control methods, such as reinforcement learning (RL). RL is an active branch of the machine learning research field, where control of a system is learned through interaction with the environment. Thus, RL can be seen as an automated approach to AO control, where its usage is entirely a turnkey operation. In particular, model-based RL has been shown to cope with temporal and misregistration errors. Similarly, it has been demonstrated to adapt to nonlinear wavefront sensing while being efficient in training and execution. In this work, we implement and adapt an RL method called policy optimization for AO (PO4AO) to the GPU-based high-order adaptive optics testbench (GHOST) test bench at ESO headquarters, where we demonstrate a strong performance of the method in a laboratory environment. Our implementation allows the training to be performed parallel to inference, which is crucial for on-sky operation. In particular, we study the predictive and self-calibrating aspects of the method. The new implementation on GHOST running PyTorch introduces only around 700 μs of in addition to hardware, pipeline, and Python interface latency. We open-source well-documented code for the implementation and specify the requirements for the RTC pipeline. We also discuss the important hyperparameters of the method and how they affect the method. Further, the paper discusses the source of the latency and the possible paths for a lower latency implementation.","PeriodicalId":54342,"journal":{"name":"Journal of Astronomical Telescopes Instruments and Systems","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139951928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Asgard/NOTT: L-band nulling interferometry at the VLTI. II. Warm optical design and injection system","authors":"Germain Garreau, Azzurra Bigioli, Romain Laugier, Gert Raskin, Johan Morren, Jean-Philippe Berger, Colin Dandumont, Harry-Dean Kenchington Goldsmith, Simon Gross, Michael Ireland, Lucas Labadie, Jérôme Loicq, Stephen Madden, Guillermo Martin, Marc-Antoine Martinod, Alexandra Mazzoli, Ahmed Sanny, Hancheng Shao, Kunlun Yan, Denis Defrère","doi":"10.1117/1.jatis.10.1.015002","DOIUrl":"https://doi.org/10.1117/1.jatis.10.1.015002","url":null,"abstract":"Asgard/NOTT (previously Hi-5) is a European Research Council (ERC)-funded project hosted at KU Leuven and a new visitor instrument for the Very Large Telescope Interferometer (VLTI). Its primary goal is to image the snow line region around young stars using nulling interferometry in the L′-band (3.5 to 4.0) μm, where the contrast between exoplanets and their host stars is advantageous. The breakthrough is the use of a photonic beam combiner, which only recently allowed the required theoretical raw contrast of 10−3 in this spectral range. Nulling interferometry observations of exoplanets also require a high degree of balancing between the four pupils of the VLTI in terms of intensity, phase, and polarization. The injection into the beam combiner and the requirements of nulling interferometry are driving the design of the warm optics and the injection system. The optical design up to the beam combiner is presented. It offers a technical solution to efficiently couple the light from the VLTI into the beam combiner. During the coupling, the objective is to limit throughput losses to 5% of the best expected efficiency for the injection. To achieve this, a list of different loss sources is considered with their respective impact on the injection efficiency. Solutions are also proposed to meet the requirements of beam balancing for intensity, phase, and polarization. The different properties of the design are listed, including the optics used, their alignment and tolerances, and their impact on the instrumental performances in terms of throughput and null depth. The performance evaluation gives an expected throughput loss <6.4% of the best efficiency for the injection and a null depth of ∼2.10−3, mainly from optical path delay errors outside the scope of this work.","PeriodicalId":54342,"journal":{"name":"Journal of Astronomical Telescopes Instruments and Systems","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139750440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reflectance properties of the Acktar Magic Black™ coating for the radiation near the Lyman-α line of hydrogen: measurements and phenomenological model of the BRDF","authors":"Marek Strumik, Martyna Wardzińska, Maciej Bzowski, Przemysław Wachulak, Roman Wawrzaszek, Tomasz Fok, Andrzej Bartnik, Karol Mostowy, Henryk Fiedorowicz, Łukasz Węgrzyński, Mateusz Majszyk","doi":"10.1117/1.jatis.10.1.018004","DOIUrl":"https://doi.org/10.1117/1.jatis.10.1.018004","url":null,"abstract":"Optical surfaces of space instruments usually need to be blackened to minimize adverse effects affecting their performance in photometric, spectrometric, and imaging applications. Blackening is often obtained by application of coatings that strongly absorb the incoming photon flux and diffusively scatter the incident photons. We discuss reflectance measurements and a phenomenological model of the bidirectional reflectance distribution function (BRDF) for the Magic Black™ coating, which is a commercial product supplied by the Acktar company. The coating has a vast satellite-instrument heritage and is planned to be used in the GLOWS photometer onboard the upcoming NASA Interstellar Mapping and Acceleration Probe nmission. The reflectance measurements were conducted at ∼121.6 nm, corresponding to the Lyman-α line for hydrogen, which is important in astrophysics. This line is commonly considered a crossover between the far ultraviolet and extreme ultraviolet spectral ranges. To generate radiation in this range, a laser-plasma source based on the gas-puff target was used. Six samples coated with Acktar Magic Black™ were studied in an optical system with a back-illuminated CCD camera as a detector. The measurements were used to derive the phenomenological BRDF model based on a series of analytic fits to the measurements, which makes it easily applicable in both numerical simulations and manual calculations. The formulas provide an approximation in the full hemispheric domain, i.e., both for the in-specular-plane and out-of-specular-plane behaviors of the BRDF for the coating. A similar fit-based phenomenological model is also described for the visible range (the wavelength of 532 nm) as a byproduct of our analysis for the UV range.","PeriodicalId":54342,"journal":{"name":"Journal of Astronomical Telescopes Instruments and Systems","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139750546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pathfinder value for integration and test of the Webb Telescope optical system","authors":"Tony L. Whitman","doi":"10.1117/1.jatis.10.1.011206","DOIUrl":"https://doi.org/10.1117/1.jatis.10.1.011206","url":null,"abstract":"The James Webb Space Telescope has extended our knowledge of the universe since the first images appeared last year with optical performance reaching the diffraction limit. The optical alignment and quality were tested prior to launch at cryogenic temperatures with a complex test configuration for this unique telescope architecture. This article reviews the strategic choices for pathfinding the integration and test processes for this telescope and the lessons learned prior to integrating and testing the flight hardware, leading to a successful integration and test campaign of the flight telescope. The biggest lesson was learning the value of investing in pathfinding integration and test activities.","PeriodicalId":54342,"journal":{"name":"Journal of Astronomical Telescopes Instruments and Systems","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139093683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"2023 List of Reviewers","authors":"","doi":"10.1117/1.jatis.10.1.010102","DOIUrl":"https://doi.org/10.1117/1.jatis.10.1.010102","url":null,"abstract":"JATIS thanks the reviewers who served the journal in 2023.","PeriodicalId":54342,"journal":{"name":"Journal of Astronomical Telescopes Instruments and Systems","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139423783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Webb Space Telescope primary mirror development: summary and lessons learned","authors":"H. Philip Stahl","doi":"10.1117/1.jatis.10.1.011207","DOIUrl":"https://doi.org/10.1117/1.jatis.10.1.011207","url":null,"abstract":"The primary mirror is central to the success of the Webb Space Telescope and the product of 100s of engineers and technologists who invented technologies and processes for its manufacture and test. We summarize the Webb mirror technology development program, explain how the technology was demonstrated to be TRL-6 (including the importance of an Engineering Development Unit), and list some of the author’s personal lessons learned.","PeriodicalId":54342,"journal":{"name":"Journal of Astronomical Telescopes Instruments and Systems","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139421654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Maunakea Spectroscopic Explorer exposure time calculator for end-to-end simulator: to optimizing spectrograph design and observing simulation","authors":"Tae-Geun Ji, Jennifer Sobeck, Changgon Kim, Hojae Ahn, Mingyeong Yang, Taeeun Kim, Sungwook E. Hong, Kei Szeto, Jennifer L. Marshall, Christian Surace, Soojong Pak","doi":"10.1117/1.jatis.10.1.018001","DOIUrl":"https://doi.org/10.1117/1.jatis.10.1.018001","url":null,"abstract":"The Maunakea Spectroscopic Explorer (MSE) project will provide multi-object spectroscopy in the optical and near-infrared bands using an 11.25-m aperture telescope, repurposing the original Canada–France–Hawaii Telescope site. MSE will observe 4332 objects per single exposure with a field of view of 1.5 square degrees, utilizing two spectrographs with low-moderate (R∼3000, 6000) and high (R≈30,000) spectral resolution. In general, an exposure time calculator (ETC) is used to estimate the performance of an observing system by calculating the signal- to-noise ratio (S/N) and exposure time. We present the design of the MSE ETC, which has four calculation modes (S/N, exposure time, S/N trend with wavelength, and S/N trend with magnitude) and incorporates the MSE system requirements as specified in the conceptual design. The MSE ETC currently allows for user-defined inputs of the target AB magnitude, water vapor, air mass, and sky brightness AB magnitude (additional user inputs can be provided depending on the computational mode). The ETC is built using Python 3.7 and features a graphical user interface that allows for cross-platform use. The development process of the ETC software follows an Agile methodology and utilizes the unified modeling language diagrams to visualize the software architecture. We also describe the testing and verification of the MSE ETC.","PeriodicalId":54342,"journal":{"name":"Journal of Astronomical Telescopes Instruments and Systems","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139102601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}