HEX-P is a probe-class mission concept that will combine high angular resolution (⪅ 5 ′′ at 6 keV) x-ray imaging and broad energy sensitivity (0.2 − 80 keV) to enable revolutionary new insights into black holes, neutron stars, and other extreme environments powering the high energy universe. HEX-P prioritizes broad band imagery and high resolution simultaneously, providing a wealth of information not possible with any other planned or operating observatory. HEX-P achieves its breakthrough performance by combining technologies developed by experienced partners: high resolution low energy imagery with silicon segmented mirrors provided by the Goddard Space Flight Center (GSFC, Greenbelt, MD); state of the art high energy imagery from nickel shell mirror technology developed by Media Lario (Bosisio Parini, Italy) and the National Institute for Astrophysics (INAF, Merate, Italy) through a contribution from the Italian Space Agency (ASI, Rome, Italy); high speed, high resolution Depleted P-Channel Field Effect Transistor (DEPFET) detectors through a contribution from the Max Planck Institute for Extraterrestrial Physics (MPE, Garching, Germany); photon counting high energy detectors from the NuSTAR team at the California Institute of Technology (Caltech, Pasadena CA); and a spacecraft and payload structure with a 20 m deployable boom developed by Northrop Grumman (Falls Church, VA).
KEYWORDS: Cameras, Sun, Calibration, Mirrors, Space operations, Contamination, Field programmable gate arrays, Electronics, Telescopes, Control systems
eROSITA (extended ROentgen Survey with an Imaging Telescope Array) is the soft X-ray scientific payload on board the SRG (Spektrum-Roentgen-Gamma) mission. It was successfully launched from Baikonur in July 2019. Following a 101 days cruise phase, SRG reached its final orbit around the Sun-Earth Lagrangian point L2, from where it has carried out already four full-sky surveys. eROSITA is a complex instrument composed of seven identical co-aligned X-ray telescopes with a focal length of 1600mm and an aperture of 350mm. Each telescope is equipped with an independent CCD camera. The cold redundant ITC (Interface and Thermal Controller) manages all seven cameras as well as the thermal control of the telescope and the interface to the spacecraft. The cruise phase of SRG was used to verify that all systems had survived launch and no degradation in the functionality was present. Following that, the main science mission, comprised of an early Calibration and Performance Verification Phase, followed by the all-sky survey. This paper presents the performance of the eROSITA telescope during the first four complete all-sky surveys. It presents the challenges encountered during the telescope operations as well as the operations and mitigation strategies put in place to understand or minimize the effects of the space environment in L2, such as micrometeoroid hits and radiation damage of the detectors.
Micrometeoroids are micron-sized dust particles orbiting at hypervelocities of a few tens of kilometers per second. Impacts on sensitive x-ray astronomical devices in space can degrade their performance and even lead to fatal loss of at least parts of their functionality, like in the case of two CCDs of the EPIC MOS1 camera aboard XMM-Newton. We summarize here the main parameters and effects of such micrometeoroid impacts on x-ray astronomical instrumentation in space, to serve as quick reference on this subject, e.g. for subsequent comparative studies. In particular, we list all related SRG/eROSITA events registered during the first two years of operations at the sun-Earth L2 point. None of these seven events has lead to any failure or significant reduction of instrument performance. Only bright pixels and column segments developed. They were either set to bad onboard or could be cured by computation of new offset maps or commanding of higher thresholds for individual pixels. Only one case was clearly associated with an intense optical light flash. Finally, we compare the number of registered events to predictions from interplanetary dust models of sporadic meteoroids from the interplanetary dust cloud and cometary meteoroid streams. The modelled dust fluxes for approximately 1 µm sized sporadic particles are in rough agreement with the number of events registered by eROSITA, while cometary meteoroid streams can most likely be excluded as origin of eROSITA hits.
KEYWORDS: Clocks, Sensors, Oscillators, Electronics, Space operations, Picosecond phenomena, Field programmable gate arrays, X-ray telescopes, Signal detection, Field effect transistors
The wide field imager (WFI) is one of two instruments of the x-ray advanced telescope for high-energy astrophysics (Athena) mission selected by ESA. The WFI instrument uses a camera with a DEPFET sensor, Detector electronics (DE) to control the camera, and additional electronics units to communicate with the spacecraft on-board-computer (OBC). The spacecraft event time (SCET) is generated on the OBC and synchronized with ground. The SCET timing synchronization between the OBC and the sensor photon detection presents particular challenges. The science user requirement of the absolute knowledge error of the WFI time stamp relative to the OBC clock is 5 µs with a confidence level of 99.73%. In this paper, we present the WFI timing distribution implementation. The three main contributors of the timing distribution are: (1) time delays and jitter between OBC and DE, (2) internal delays of the DE, and (3) delay between a photon capture and the time stamping in the DE. The first contributor is the most critical and two solving methods are identified. The first method uses only the timecode of the SpaceWire (SpW) communication network, and the second method uses a combination of pulse-per-second (PPS) signal and SpW network. SpW network standard was published in 2003 and few missions such as ESA solar orbiter use it exclusively for time distribution. In our analysis, we found that using the second method with a PPS signal, delays contribution is in order of nanoseconds.
This conference presentation was prepared for the Space Telescopes and Instrumentation 2022: Ultraviolet to Gamma Ray conference at SPIE Astronomical Telescopes + Instrumentation, 2022.
eROSITA (extended ROentgen Survey with an Imaging Telescope Array) is the primary scientific payload on board the SRG (Spektrum Röntgen Gamma) mission, successfully launched from Baikonur in July 2019. Following a 101 days cruise phase, SRG reached its final orbit around the Lagrangian point L2, where it will carry out its mission of making a full survey of the X-ray sky. eROSITA is a complex instrument composed of seven identical co-aligned X-ray telescopes with a focal length of 1600mm and an aperture of 350mm. Each telescope is equipped with an independent CCD camera. The cold redundant ITC (Interface and Thermal Controller) manages all seven cameras as well as the thermal control of the telescope and the interface to the spacecraft. The cruise phase of SRG was used to verify that all systems had survived launch and no degradation in the functionality was present. In addition, the critical one-time operations of opening the telescope cover and cooling the CCD detectors to -90°C were carried out during this phase. The extreme reliance on the instrument controller (ITC) for the survival of the telescope, in addition to the thermal control an data handling systems that are under control of the ITC, make it pertinent to report on how these systems behaved in the initial phases of the mission. This paper presents an overview of the telescope operations during the early phase and commissioning that verified functionality of thermal and electrical systems and commissioned the cameras before the important Calibration and Pointed Verification phase started. In addition, it reports on the challenges encountered and summarizes the results from this phase of eROSITA operations.
eROSITA (extended ROentgen Survey with an Imaging Telescope Array) is the main instrument onboard the Russian/German "Spectrum-Roentgen-Gamma" (SRG) mission which will be operated in an L2 orbit. It will perform the first imaging all-sky survey in the medium energy band. The main scientific goals are a) to detect the hot intergalactic medium of ~100 thousand galaxy clusters and groups and hot gas in filaments between clusters to map out the large scale structure in the Universe for the study of cosmic structure evolution, b) to detect systematically all obscured accreting Black Holes in nearby galaxies and many (up to 3 Million) new, distant active galactic nuclei, and c) to study in detail the physics of galactic X-ray source populations, like pre-main sequence stars, supernova remnants and X-ray binaries. The eROSITA flight model was assembled in 2016 and has successfully passed all acceptance tests on instrument level in the facilities of MPE and IABG in Germany. eROSITA was shipped to NPOL (SRG prime contractor) in January 2017. Currently (May 2018) eROSITA has been integrated on the SRG spacecraft and has successfully passed all functional tests. eROSITA is now awaiting its launch from the Baikonur cosmodrome in spring 2019. The launcher will be a PROTON with an upper stage BLOK-DM.
eROSITA (extended ROentgen Survey with an Imaging Telescope Array) is the primary instrument on-board the Russian/German "Spectrum-Roentgen-Gamma" (SRG) mission. It will perform the first all-sky imaging X-ray survey in the medium X-ray energy band. eROSITA is currently awaiting its launch from Baikonur in early 2019 into an L2 halo orbit. Preparations for eROSITA ground operations have been under way in parallel with the hardware development of the eROSITA telescope, comprising the areas mission planning, telescope operation and data reception, the operation of a data processing pipeline, and the creation of tools for data access and interactive data analysis. eROSITA mission: After a brief calibration and performance verification phase eROSITA will perform a four-year all-sky survey fully covering the sky eight times, which will be followed by several years of dedicated observations of interesting objects. Two ground antennas in Russia (near Moscow and in Siberia) will be available to provide several hours of daily ground contact for commanding and for data reception. eROSITA data rights will be equally divided between the Russian and German partners. Operation and data centers will exist at Max-Planck-Institut für extraterrestrische Physics (MPE) in Garching, Germany and at the Russian Space Research Institute (IKI) in Moscow. Interfaces and procedures for mission planning, telescope operation and data exchange are closely coordinated between both sites. Mission planning and operation: Based on orbit simulations provided by the Russian side, a software environment for optimizing the desired sky coverage and observing efficiency while fulfilling visibility and solar constraints was set up. Agreed upon observing timelines will be converted to eROSITA and SRG command sequences fed to the Russian ground station for up-linking. MPE personnel will be on site either in Moscow or at MPE in Garching during each ground contact to conduct ondemand commanding and to assess instrument health and data quality. Data analysis pipeline and interactive data analysis: The eROSITA data processing pipeline consists of modules for data ingestion, event calibration, exposure calculation, source detection, and the creation of high-level source specific data products. It will be operated at MPE on a daily basis after each ground contact. A subset of the software tasks comprising the data analysis pipeline also functions as interactive data analysis tools. These can be grouped into tasks for X-ray event calibration, selection and binning, exposure, background and sensitivity map creation and for source detection. Data products are provided in a standards compliant FITS format for use with well-known high-level X-ray data analysis tools. A Web based graphical source catalog and data products viewer will allow easy data browsing. Since mid-2014 the interactive eROSITA data analysis package is available to the eROSITA user community, permitting the analysis of simulated eROSITA datasets, created by a sophisticated X-ray modeling and simulation tool.
eROSITA (extended ROentgen Survey with an Imaging Telescope Array) is the primary scientific payload on board the SRG (Spektrum Röntgen Gamma) mission, scheduled for launch in March 2019. Its destination is the Lagrangian point L2, and its mission is to make a full survey of the X-ray sky. eROSITA is a complex instrument composed of seven identical co-aligned X-ray telescopes with a focal length of 1600mm and an aperture of 7x350mm. Each telescope is equipped with an independent CCD camera. The cold redundant ITC manages all seven cameras as well as the thermal control of the telescope and the interface to the spacecraft. The complexity of this system resides in the fact that the hardware and software interfaces to the spacecraft are minimal. In this respect the ITC has a key role in the management of the instrument, as well as in the science data management. This proved to be an optimal solution in terms of instrument flexibility, but also presented some challenges. The paper presents an overview on the eROSITA system functionality, its interfaces and operational modes together with an outline of the main challenges, which were faced during integration and verification of the complete system. The function of the instrument was verified in the frame of an extensive end-to-end test in vacuum under representative thermal control conditions to verify that the instrument functions under worst case conditions. Currently tests are performed in combination with the spacecraft to verify communication between eROSITA and the spacecraft and the data transfer through the Russian radio complex (TM/TC system). This includes all operational and survival modes. The paper summarizes the main results of the functional tests on instrument level and on spacecraft level.
eROSITA (extended ROentgen Survey with an Imaging Telescope Array) is the core instrument on the Russian/German Spektrum-Roentgen-Gamma (SRG) mission which is now officially scheduled for launch on September 2017, eROSITA will perform a deep survey of the entire X-ray sky. Within the first 4 years of the mission the sky will be scanned 8 times. In the soft band (0.5-2 keV), it will be about 30 times more sensitive than ROSAT, while in the hard band (2-8 keV) it will provide the first ever true imaging survey of the sky. eROSITA is currently (June 2016) in its final integration and test phase. All seven FM Mirror Assemblies and Camera Assemblies (+ 1 spare) have been tested and calibrated. All subsystems and components are well within their expected performances.
eROSITA (extended ROentgen Survey with an Imaging Telescope Array) is the core instrument on the Russian/German Spektrum-Roentgen-Gamma (SRG) mission which is now officially scheduled for launch on March 26, 2016. eROSITA will perform a deep survey of the entire X-ray sky. In the soft band (0.5-2 keV), it will be about 30 times more sensitive than ROSAT, while in the hard band (2-8 keV) it will provide the first ever true imaging survey of the sky. The design driving science is the detection of large samples of galaxy clusters to redshifts z < 1 in order to study the large scale structure in the universe and test cosmological models including Dark Energy. In addition, eROSITA is expected to yield a sample of a few million AGN, including obscured objects, revolutionizing our view of the evolution of supermassive black holes. The survey will also provide new insights into a wide range of astrophysical phenomena, including X-ray binaries, active stars and diffuse emission within the Galaxy. eROSITA is currently (June 2014) in its flight model and calibration phase. All seven flight mirror modules (+ 1 spare) have been delivered and measured in X-rays. The first camera including the complete electronics has been extensively tested (vacuum + X-rays). A pre-test of the final end-toend test has been performed already. So far, all subsystems and components are well within their expected performances.
The eROSITA space telescope is currently developed for the determination of cosmological parameters and the equation of state of dark energy via evolution of clusters of galaxies. Furthermore, the instrument development was strongly motivated by the intention of a first imaging X-ray all-sky survey enabling measurements above 2 keV. eROSITA is a scientific payload on the Russian research satellite SRG. Its destination after launch is the Lagrangian point L2. The observational program of the observatory divides into an all-sky survey and pointed observations and takes in total about 7.5 years. The instrument comprises an array of 7 identical and parallel aligned telescopes. Each of the seven focal plane cameras is equipped with a PNCCD detector, an enhanced type of the XMM-Newton focal plane detector. This instrumentation permits spectroscopy and imaging of X-rays in the energy band from 0.3 keV to 10 keV with a field of view of 1.0 degree. The camera development is done at the Max-Planck-Institute for extraterrestrial physics. Key component of each camera is the PNCCD chip. This silicon sensor is a back-illuminated, fully depleted and column-parallel type of charge coupled device. The image area of the 450 micron thick frame-transfer CCD comprises an array of 384 x 384 pixels, each with a size of 75 micron x 75 micron. Readout of the signal charge that is generated by an incident X-ray photon in the CCD is accomplished by an ASIC, the so-called eROSITA CAMEX. It provides 128 parallel analog signal processing channels but multiplexes the signals finally to one output which feeds the detector signals to a fast 14-bit ADC. The read noise of this system is equivalent to a noise charge of about 2.5 electrons rms. We achieve an energy resolution close to the theoretical limit given by Fano noise (except for very low energies). For example, the FWHM at an energy of 5.9 keV is approximately 140 eV. The complete camera assembly comprises the camera head with the detector as key component, the electronics for detector operation as well as data acquisition and the filter wheel unit. In addition to the on-chip light blocking filter directly deposited on the photon entrance window of the PNCCD, an external filter can be moved in front of the sensor, which serves also for contamination protection. Furthermore, an on-board calibration source emitting several fluorescence lines is accommodated on the filter wheel mechanism for the purpose of in-orbit calibration. Since the spectroscopic silicon sensors need cooling down to -95°C to mitigate best radiation damage effects, an elaborate cooling system is necessary. It consists of two different types of heat pipes linking the seven detectors to two radiators. Based on the tests with an engineering model, a flight design was developed for the camera and a qualification model has been built. The tests and the performance of this camera is presented in the following. In conclusion an outlook on the flight cameras is given.
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