Time assignment system and its performance aboard the Hitomi satellite

X-Ray Imaging and Spectroscopy Mission (XRISM) is an x-ray astronomical mission led by the Japan Aerospace Exploration Agency (JAXA) and National Aeronautics and Space Administration (NASA), with collaboration from the European Space Agency (ESA) and other international participants, that is planned for launch in 2022 (Japanese fiscal year), to quickly restore high-resolution x-ray spectroscopy of astrophysical objects using the microcalorimeter array after the loss of Hitomi satellite. In order to enhance the scientific outputs of the mission, the Science Operations Team (SOT) is structured independently from the Instrument Teams (ITs) and the Mission Operations Team. The responsibilities of the SOT are divided into four categories: (1) guest observer program and data distributions, (2) distribution of analysis software and the calibration database, (3) guest observer support activities, and (4) performance

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Section: Lessons Learned From Hitomimentioning

confidence: 99%

Detailed design of the science operations for the XRISM mission

Terada

Holland

Loewenstein

et al. 2021

J. Astron. Telesc. Instrum. Syst.

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“…As a result, there were no delays in the schedule of software preparation and no delay in the release of tools and the calibration database. The products were well calibrated using instrument-specific methods, [12][13][14][15][16][17][18][19][20][21] because all the algorithms were imported into the analysis software and the latest calibration information was quickly released in the database. 5 2d-Hitomi − : In order to achieve 2c-Hitomi + , there were many interactions among the software and calibration team, instrument teams, and operation teams, which were spread across multiple agencies.…”

Section: Lessons Learned From Hitomimentioning

confidence: 99%

Detail plans and preparations for the science operations of the XRISM mission

Terada

Holland

Loewenstein

et al. 2020

Space Telescopes and Instrumentation 2020: Ultraviolet to Gamma Ray

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XRISM is an X-ray astronomical mission led by the Japan Aerospace Exploration Agency (JAXA) and National Aeronautics and Space Administration (NASA), with collaboration from the European Space Agency (ESA) and other international participants, that is planned for launch in 2022 (Japanese fiscal year), to quickly restore high-resolution X-ray spectroscopy of astrophysical objects using the micro-calorimeter array after the loss of Hitomi satellite. In order to enhance the scientific outputs of the mission, the Science Operations Team (SOT) is structured independently from the instrument teams and the Mission Operations Team (MOT). The responsibilities of the SOT are divided into four categories: 1) guest observer program and data distributions, 2) distribution of analysis software and the calibration database, 3) guest observer support activities, and 4) performance verification and optimization activities. Before constructing the operations concept of the XRISM mission, lessons on the science operations learned from past Japanese X-ray missions (ASCA, Suzaku, and Hitomi) are reviewed, and 15 kinds of lessons are identified by categories, such as lessons on the importance of avoiding nonpublic ("animal") tools, coding quality of public tools in terms of both the engineering viewpoint and calibration accuracy, tight communications with instrument teams and operations teams, well-defined task division between scientists and engineers, etc. Among these lessons, a) the importance of early preparation of the operations from the ground stage, b) construction of an independent team for science operations separate from the instrument development, and c) operations with well-defined duties by appointed members are recognized as key lessons for XRISM. Based on this, i) the task division between the mission and science operations and ii) the subgroup structure within the XRISM team are defined in detail as the XRISM Operations Concept. Based on this operations concept, the detailed plan of the science operations is designed as follows. The science operations tasks are shared among Japan, the US, and Europe and are performed by three centers: the Science Operations Center (SOC) at JAXA, the Science Data Center (SDC) at NASA, and European Space Astronomy Centre (ESAC) at the ESA. The SOT is defined as a combination of the SOC and SDC. The SOC is designed to perform tasks close to the spacecraft operations, such as spacecraft planning of science targets, quick-look health checks, pre-pipeline data processing, etc., and the SDC covers tasks regarding data calibration processing (pipeline processing), maintenance of analysis tools, etc. The data-archive and user-support activities are planned to be covered both by the SOC and SDC. Finally, the details of the science operations tasks and the tools for science operations are defined and prepared before launch. This information is expected to be helpful for the construction of science operations of future X-ray missions.

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“…The requirement for the absolute time precision with 1 μs is less stringent. Just to compare the magnitude of the synchronization requirements, in the other system such as the Hitomi satellite, 19 a 35 μs is demanded for proper operation, and in SKA telescope, a nanosecond range synchronization is also needed. 20 Gamma-ray Cherenkov telescope (GCT) is a consortium to provide the SSTs as an in-kind contribution to the CTA observatory.…”

Section: Cherenkov Telescope Arraymentioning

confidence: 99%

Optimized framegrabber for the Cherenkov telescope array

Jiménez-López

Machado-Cano

Rodríguez-Álvarez

et al. 2019

J. Astron. Telesc. Instrum. Syst.

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Our contribution presents a high bandwidth platform that implements traffic aggregation and switching capabilities for the Cherenkov telescope array (CTA) cameras. Our proposed system integrates two different data flows: a unidirectional one from the cameras to an external server and a second one, fully configurable dedicated to configuration and control traffic for the camera management. The former requires high bandwidth mechanisms to be able to aggregate several 1 gigabit Ethernet links into one high speed 10 gigabit Ethernet port. The latter is responsible for providing routing components to allow a control and management path for all the elements of the cameras. Hence, a simple, efficient, and flexible routing mechanism has been implemented avoiding complex circuitry that impacts in the system performance. As a consequence, an asymmetric network topology allows high bandwidth communication and, at the same time, a flexible and cost-effective implementation. In our contribution, we analyze the camera requirements and present the proposed architecture. Moreover, we have designed several evaluation tests to demonstrate that our solution fulfills the CTA project needs. Finally, we illustrate the general possibilities of the proposed solution for other data acquisition applications and the most promising futures lines of research are discussed.

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Time assignment system and its performance aboard the Hitomi satellite

Cited by 8 publications

References 11 publications

Detailed design of the science operations for the XRISM mission

Detailed design of the science operations for the XRISM mission

Detail plans and preparations for the science operations of the XRISM mission

Optimized framegrabber for the Cherenkov telescope array

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