Large-format infrared detectors are at the heart of major ground and space-based astronomical instruments, and the HgCdTe HxRG is the most widely used. The Near Infrared Spectrometer and Photometer (NISP) of the ESA’s Euclid mission launched in July 2023 hosts 16 H2RG detectors in the focal plane. Their performance relies heavily on the effect of image persistence, which results in residual images that can remain in the detector for a long time contaminating any subsequent observations. Deriving a precise model of image persistence is challenging due to the sensitivity of this effect to observation history going back hours or even days. Nevertheless, persistence removal is a critical part of image processing because it limits the accuracy of the derived cosmological parameters. We will present the empirical model of image persistence derived from ground characterization data, adapted to the Euclid observation sequence and compared with the data obtained during the in-orbit calibrations of the satellite.
Launched successfully on July 1st, 2023, Euclid, the M2 mission of the ESA cosmic vision program, aims mainly at understanding the origin of the accelerated expansion of the Universe. Along with a visible imager VIS, it is equipped with the NISP instrument, a Near Infrared Spectrometer and Photometer, bespoke tailored to perform a 3D mapping of the observable Universe. It operates in the near-infrared spectral range, from 900 nm to 2000 nm with 2 observing modes: as a spectrometer, the NISP instrument will permit measuring millions of galaxy spectroscopic redshifts over the 6.5 years lifetime of the Euclid mission; as a photometer, it will obtain photometric redshifts of billions of galaxies. This paper provides a description of the NISP instrument, its scientific objectives, and offers an assessment of its current performance in flight.
The Heterodyne Spectrometer Instrument (HSI) is one of two instruments designed for the Far-IR Spectroscopy Space Telescope (FIRSST) recently proposed to NASA in response to the Astrophysics Probe Explorer call. HSI will be the first THz cryogenic heterodyne array receiver implemented for a space mission. It has extremely high spectral resolving power (R>10^6) in order to allow detailed spectral observations. HSI covers a very wide bandwidth range between 150 and 600 microns in only 3 bands, each equipped with two 5-pixel arrays. HSI enables highly sensitive dual-polarization, multi-pixel and multi-frequency observations on a space telescope, by a careful design and by employing low-heat dissipating, low-power, but high TRL components.
The ARIEL mission has the task of conducting a large, unbiased spectroscopic survey of exoplanets, in order to explore the nature of exoplanet atmospheres and interiors and, through this, the key factors affecting the formation and evolution of planetary systems in our galaxy. Ariel is composed of two scientific instrument: one is the FGS which provides the Fine Guidance System capabilities and in addition combines a VIS photometer and a NIR low resolution spectrometer. The other instrument is the Ariel IR Spectrometer (AIRS) which provides spectra with resolution between 30 and 100 on a spectral band between 1.95 and 7.8 micrometers. This paper will focus on the application SW of the Instrument Control Unit of the Ariel mission, which is in charge of controlling the AIRS instrument as well as the Telescope Control Unit (TCU), which controls the M2 Mirror Mechanism (M2M) and provides the temperatures of the Payload. In particular, we will discuss the design of the ASW and the development status of the SW. The Ariel ICU is based on a dual core Leon3-FT processor; the ASW is based on the space profile of the Multiprocessor version of RTEMS 6; we plan to use the multicore nature of the processor to separate the control functions from the data processing part (mainly compression). The ASW implements several standard PUS services, plus a set of instrument specific services for controlling the AIRS Detector Control Units (DCU) and the TCU. We will discuss the results of the coupling tests that have been performed to verify the communications between the ICU and the subsystems (DCUs and TCU), as well as between the ICU and the platform (using a dedicated Spacecraft Interface Simulator)
Ariel is the M4 mission of the ESA’s Cosmic Vision Program 2015-2025, whose aim is to characterize by lowresolution transit spectroscopy the atmospheres of over one thousand warm and hot exoplanets orbiting nearby stars. It has been selected by ESA in March 2018 and adopted in November 2020 to be flown, then, in 2029. It is the first survey mission dedicated to measuring the chemical composition and thermal structures of the atmospheres of hundreds of transiting exoplanets, in order to enable planetary science far beyond the boundaries of the Solar System. The Payload (P/L) is based on a cold section (PLM – Payload Module) working at cryogenic temperatures and a warm section, located within the Spacecraft (S/C) Service Vehicle Module (SVM) and hosting five warm units operated at ambient temperature (253-313 K). The P/L and its electrical, electronic and data handling architecture has been designed and optimized to perform transit spectroscopy from space during primary and secondary planetary eclipses in order to achieve a large set of unbiased observations to shed light and fully understand the nature of exoplanets atmospheres, retrieving information about planets interior and determining the key factors affecting the formation and evolution of planetary systems.
Euclid, the M2 mission of the ESA’s Cosmic Vision 2015-2025 program, aims to explore the Dark Universe by conducting a survey of approximately 14 000 deg2 and creating a 3D map of the observable Universe of around 1.5 billion galaxies up to redshift z ∼ 2. This mission uses two main cosmological probes: weak gravitational lensing and galaxy clustering, leveraging the high-resolution imaging capabilities of the Visual Imaging (VIS) instrument and the photometric and spectroscopic measurements of the Near Infrared Spectrometer and Photometer (NISP) instrument. This paper details some of the activities performed during the commissioning phase of the NISP instrument, following the launch of Euclid on July 1, 2023. In particular, we focus on the calibration of the NISP detectors’ baseline and on the performance of a parameter provided by the onboard data processing (called NISP Quality Factor, QF) in detecting the variability of the flux of cosmic rays hitting the NISP detectors. The NISP focal plane hosts sixteen Teledyne HAWAII-2RG (H2RG) detectors. The calibration of these detectors includes the baseline optimization, which optimizes the dynamic range and stability of the signal acquisition. Additionally, this paper investigates the impact of Solar proton flux on the NISP QF, particularly during periods of high Solar activity. Applying a selection criterion on the QF (called NISP QF Proxy), the excess counts are used to monitor the amount of charged particles hitting the NISP detectors. A good correlation was found between the Solar proton flux component above 30 MeV and the NISP QF Proxy, revealing that NISP detectors are not subject to the lower energy components, which are absorbed by the shielding provided by the spacecraft.
ARIEL (Atmospheric Remote-sensing InfraRed Large-survey) is the fourth medium-class mission (M4) of the European Space Agency, part of the Cosmic Vision program, whose launch is planned by late 2029. ARIEL aims to study the composition of exoplanet atmospheres, their formation and evolution. The ARIEL’s target will be a sample of about 1000 planets observed with one or more of the following methods: transit, eclipse and phase-curve spectroscopy, in both visible and infrared light. The scientific payload is composed by a reflective telescope having a 1m-class elliptical primary mirror, built in solid Aluminum, and two focal-plane instruments: FGS and AIRS. FGS (Fine Guidance System)3 has the double purpose of performing photometry (0.50-0.55 µm) and low resolution spectrometry over three bands (from 0.8 to 1.95 µm) and, simultaneously, to provide data to the spacecraft AOCS (Attitude and Orbit Control System). AIRS (ARIEL InfraRed Spectrometer) instrument will perform IR spectrometry in two wavelength ranges: between 1.95 and 3.9 µm (with a spectral resolution R > 100) and between 3.9 and 7.8 µm with a spectral resolution R > 30. This paper provides the status of the ICU (Instrument Control Unit), an electronic box whose purpose is to command and supply power to the AIRS warm front-end (as well as acquire science data from its two channels) and to command and control the TCU (Telescope Control Unit).
AIRS is the infrared spectroscopic instrument of ARIEL: Atmospheric Remote‐sensing Infrared Exoplanet Large‐survey mission adopted in November 2020 as the Cosmic Vision M4 ESA mission and planned to be launched in 2029 by an Ariane 6 from Kourou toward a large amplitude orbit around L2 for a 4-year mission. Within the scientific payload, AIRS will perform transit spectroscopy of over 1000 exoplanets to complete a statistical survey, including gas giants, Neptunes, super-Earths and Earth-size planets around a wide range of host stars. All these collected spectroscopic data will be a major asset to answer the key scientific questions addressed by this mission: what are exoplanets made of? How do planets and planetary systems form? How do planets and their atmospheres evolve over time? The AIRS instrument is based on two independent channels covering 1.95-3.90 µm (CH0) and 3.90-7.80 µm (CH1) wavelength ranges with prism-based dispersive elements producing spectra of low resolutions R>100 in CH0 and R>30 in CH1 on two independent detectors. The spectrometer is designed to provide a Nyquist-sampled spectrum in both spatial and spectral directions to limit the sensitivity of measurements to the jitter noise and intra pixels pattern during the long (10 hours) transit spectroscopy exposures. A full instrument overview will be presented covering the thermo-mechanical design of the instrument functioning in a 60 K environment, up to the detection and acquisition chain of both channels based on 2 HgCdTe detectors actively cooled to below 42 K. This overview will present updated information of phase C studies, in particular on the assembly and testing of prototypes that are highly representative of the future engineering model that will be used as an instrument-level qualification model.
Euclid is a European Space Agency (ESA) wide-field space mission dedicated to the high-precision study of dark energy and dark matter. In July 2023 a Space X Falcon 9 launch vehicle put the spacecraft in its target orbit, located 1.5 million kilometers away from Earth, for a nominal lifetime of 6.5 years. The survey will be realized through a wide field telescope and two instruments: a visible imager (VIS) and a Near Infrared Spectrometer and Photometer (NISP). NISP is a state-of-the-art instrument composed of many subsystems, including an optomechanical assembly, cryogenic mechanisms, and active thermal control. The Instrument Control Unit (ICU) is interfaced with the SpaceCraft and manages the commanding and housekeeping production while the high-performance Data Processing Unit manages more than 200 Gbit of compressed data acquired daily during the nominal survey. To achieve the demanding performance necessary to meet the mission’s scientific goals, NISP requires periodic in-flight calibrations, instrument parameters monitoring, and careful control of systematic effects. The high stability required implies that operations are coordinated and synchronized with high precision between the two instruments and the platform. Careful planning of commanding sequences, lookahead, and forecasting instrument monitoring is needed, with greater complexity than previous survey missions. Furthermore, NISP is operated in different environments and configurations during development, verification, commissioning, and nominal operations. This paper presents an overview of the NISP instrument operations at the beginning of routine observations. The necessary tools, workflows, and organizational structures are described. Finally, we show examples of how instrument monitoring was implemented in flight during the crucial commissioning phase, the effect of intense Solar activity on the transmission of onboard data, and how IOT successfully addressed this issue.
MOSAIC is the Multi-Object Spectrograph (MOS) for the 39m Extremely Large Telescope (ELT) of the European Southern Observatory (ESO), with unique capabilities in terms of multiplex, wavelength coverage and spectral resolution. It is a versatile multi-object spectrograph working in both the Visible and NIR domains, designed to cover the largest possible area (∼40 arcmin2) on the focal plane, and optimized to achieve the best possible signal-to-noise ratio on the faintest sources, from stars in our Galaxy to galaxies at the epoch of the reionization. In this paper we describe the main characteristics of the instrument, including its expected performance in the different observing modes. The status of the project will be briefly presented, together with the positioning of the instrument in the landscape of the ELT instrumentation. We also review the main expected scientific contributions of MOSAIC, focusing on the synergies between this instrument and other major ground-based and space facilities.
KEYWORDS: Sensors, X-rays, Electronics, Signal detection, Field programmable gate arrays, Amplifiers, System on a chip, Software development, Prototyping, Data compression
In this paper we describe the current development state of the Athena X-IFU instrument control unit and its application software. Athena is a ESA large mission scheduled for launch in the early 2030s, that has reached the instrument requirement review phase. Not all of the needed functionalities are frozen yet, but the baseline concept and implementation will be described. While the hardware part will be based on well developed solution, some of the software functionalities, in particular the OBCP engine, will need to be developed and qualified. We will describe our approach for development and testing. The X-IFU instrument will use a Spacewire network for communications with the platform and internally between the ICU and the other subsystems, with the ICU providing the routing capabilities for housekeeping telemetry and telecommand as well as the scientific data. We will describe some aspects of the implementation of such a network.
The NISP (Near Infrared Spectrometer and Photometer) is one of the two Euclid instruments (see ref [1]). It operates in the near-IR spectral region (950-2020nm) as a photometer and spectrometer. The instrument is composed of: - a cold (135K) optomechanical subsystem consisting of a Silicon carbide structure, an optical assembly, a filter wheel mechanism, a grism wheel mechanism, a calibration unit and a thermal control system - a detection system based on a mosaic of 16 H2RG with their front-end readout electronic. - a warm electronic system (290K) composed of a data processing / detector control unit and of an instrument control unit that interfaces with the spacecraft via a 1553 bus for command and control and via Spacewire links for science data This paper presents: - the final architecture of the flight model instrument and subsystems - the performances and the ground calibration measurement done at NISP level and at Euclid Payload Module level at operational cold temperature.
ESA’s mission Euclid while undertaking its final integration stage is fully qualified. Euclid will perform an extra galactic survey (0<z<2) using visible and near-infrared light. To detect the infrared radiation is equipped with the Near Infrared Spectro-Photometer (NISP) instrument with a sensitivity in the 0.9-2 μm range. We present an illustration of the NISP Data Processing Unit’s Application Software, highlighting the experimental process to obtain the final parametrization of the on-board processing of data produced by an array of 16 Teledyne’s HAWAII-2RG (HgCdTe) - each of 2048×2048 px2, 0.3 arcsec/px, 18 μm pixel pitch; using data from the latest test campaigns done with the flight configuration hardware - complete optical system (Korsh anastigmat telescope), detectors array (0.56 deg2 firld of view) and readout systems (16 Digital Control Units and Sidecar ASICs). Also, we show the outstanding Spectrometric (using a Blue and two Red Grisms) and Photometric (using YE 0.92-1.15μm, JE 1.15-1.37μm, and HE 1.37-2.0 μm filters) performances of the NISP detector derived from the end-to-end payload module test campaign at FOCAL 5 - CSL; among them the Photometric Point Spread Function (PSF) determination, and the Spectroscopic dispersion verification. Also the performances of the onboard processing are presented. Then, we describe the solution of a major issue found during this final test phase that put NISP in the critical path. We will describe how the problem was eventually understood and solved thanks to an intensive coordinated effort of an independent review team (tiger team lead by ESA) and a team of NISP experts from the Euclid Consortium. An extended PLM level campaign in ambient in Liege and a dedicated test campaign conducted in Marseille on the NISP EQM model, with both industrial and managerial support, finally confirmed the correctness of the diagnosis of the problem. Finally, the Euclid’s survey is presented (14000 deg2 wide survey, and ∼40 deg2 deep-survey) as well as the global statistics for a mission lifetime of 6 years (∼1.5 billion Galaxy’s shapes, and ∼50 million Galaxy’s spectra).
In this paper we describe the final status of the application software (ASW) of the instrument control unit (ICU) of NISP, the Near-Infrared Spectro-Photometer of the Euclid mission, as the version for Flight has been tested and delivered to the industry for the next integration phases. This software is based on a real-time operating system (RTEMS) and will interface with all the subunits of NISP, as well as the command and data management unit (CDMU) of the spacecraft for telecommand and housekeeping management. We will describe in particular the final tests and the main obstacles which had to be faced in order to implement an efficient and reliable interface with all the NISP subsystems.
KEYWORDS: Process control, Data processing, Computer architecture, Control systems, Network architectures, Amplifiers, Operating systems, Space operations
In this paper we describe the activities towards the design of a common framework for the Instrument Control and Data Processing Units for the three scientific payload instruments on board the joint ESA-JAXA SPICA mission, currently at the end of its phase A study. In this context, we started a program to assess modular architectures based on the use of a quad-core fault-tolerant LEON4 SPARC V8 processor on a SpaceWire network. We will describe the results of our initial tests using both Asymmetric Multi processing (AMP) and Symmetric Multi Processing (SMP) configurations. In addition, the possibility to adopt the RTEMS real time operating system, already space qualified on single core processors, will be evaluated both in terms of latency performances and of dynamical allocation of the resources. Finally, we will present the outline of the way forward for the next phases of the SPICA project.
KEYWORDS: Sensors, Data processing, Space operations, Data acquisition, Signal detection, Electronics, Control systems, Interfaces, Software development
In this paper we describe the application software (ASW) of the instrument control unit (ICU) of NISP, the Near-Infrared Spectro-Photometer of the Euclid mission. This software is based on a real-time operating system (RTEMS) and will interface with all the subunits of NISP, as well as the command and data management unit (CDMU) of the spacecraft for telecommand and housekeeping management.
The Euclid mission objective is to understand why the expansion of the Universe is accelerating through by mapping the geometry of the dark Universe
by investigating the distance-redshift relationship and tracing the evolution of cosmic structures. The Euclid project is part of ESA's Cosmic Vision
program with its launch planned for 2020 (ref [1]).
The NISP (Near Infrared Spectrometer and Photometer) is one of the two Euclid instruments and is operating in the near-IR spectral region (900-
2000nm) as a photometer and spectrometer. The instrument is composed of:
- a cold (135K) optomechanical subsystem consisting of a Silicon carbide structure, an optical assembly (corrector and camera lens), a filter wheel
mechanism, a grism wheel mechanism, a calibration unit and a thermal control system
- a detection subsystem based on a mosaic of 16 HAWAII2RG cooled to 95K with their front-end readout electronic cooled to 140K, integrated on a
mechanical focal plane structure made with molybdenum and aluminum. The detection subsystem is mounted on the optomechanical subsystem
structure
- a warm electronic subsystem (280K) composed of a data processing / detector control unit and of an instrument control unit that interfaces with the
spacecraft via a 1553 bus for command and control and via Spacewire links for science data
This presentation describes the architecture of the instrument at the end of the phase C (Detailed Design Review), the expected performance, the
technological key challenges and preliminary test results obtained for different NISP subsystem breadboards and for the NISP Structural and Thermal
model (STM).
KEYWORDS: Space telescopes, Space operations, Telescopes, Space operations, Local area networks, Databases, Control systems, Fermium, Frequency modulation, Device simulation, Data modeling
The Near Infrared Spectro-Photometer (NISP) on board the Euclid ESA mission will be developed and tested at various
levels of integration by using various test equipment. The Electrical Ground Support Equipment (EGSE) shall be
required to support the assembly, integration, verification and testing (AIV/AIT) and calibration activities at instrument
level before delivery to ESA, and at satellite level, when the NISP instrument is mounted on the spacecraft. In the case of
the Euclid mission this EGSE will be provided by ESA to NISP team, in the HW/SW framework called "CCS Lite", with
a possible first usage already during the Warm Electronics (WE) AIV/AIT activities. In this paper we discuss how we
will customize that "CCS Lite" as required to support both the WE and Instrument test activities. This customization will
primarily involve building the NISP Mission Information Base (the CCS MIB tables) by gathering the relevant data from
the instrument sub-units and validating these inputs through specific tools. Secondarily, it will imply developing a
suitable set of test sequences, by using uTOPE (an extension to the TCL scripting language, included in the CCS
framework), in order to implement the foreseen test procedures. In addition and in parallel, custom interfaces shall be set
up between the CCS and the NI-IWS (the NISP Instrument Workstation, which will be in use at any level starting from
the WE activities), and also between the CCS and the TCC (the Telescope Control and command Computer, to be only
and specifically used during the instrument level tests).
KEYWORDS: Data processing, Sensors, Near infrared, Spectrographs, Photometry, Data processing, Signal detection, Detection and tracking algorithms, Spectroscopy, Space operations, Image compression
The Near Infrared Spectrograph and Photometer (NISP) is one of the two instruments on board the EUCLID mission now under implementation phase; VIS, the Visible Imager is the second instrument working on the same shared optical beam. The NISP focal plane is based on a detector mosaic deploying 16x, 2048x2048 pixels^2 HAWAII-II HgCdTe detectors, now in advanced delivery phase from Teledyne Imaging Scientific (TIS), and will provide NIR imaging in three bands (Y, J, H) plus slit-less spectroscopy in the range 0.9÷2.0 micron. All the NISP observational modes will be supported by different parametrization of the classic multi-accumulation IR detector readout mode covering the specific needs for spectroscopic, photometric and calibration exposures. Due to the large number of deployed detectors and to the limited satellite telemetry available to ground, a consistent part of the data processing, conventionally performed off-line, will be accomplished on board, in parallel with the flow of data acquisitions. This has led to the development of a specific on-board, HW/SW, data processing pipeline, and to the design of computationally performing control electronics, suited to cope with the time constraints of the NISP acquisition sequences during the sky survey. In this paper we present the architecture of the NISP on-board processing system, directly interfaced to the SIDECAR ASICs system managing the detector focal plane, and the implementation of the on-board pipe-line allowing all the basic operations of input frame averaging, final frame interpolation and data-volume compression before ground down-link.
KEYWORDS: Control systems, Software development, Space operations, Data processing, Sensors, Control systems, Data acquisition, Field programmable gate arrays, Technetium, Electronics, Calibration
In this paper we describe the detailed design of the application software (ASW) of the instrument control unit (ICU) of
NISP, the Near-Infrared Spectro-Photometer of the Euclid mission. This software is based on a real-time operating
system (RTEMS) and will interface with all the subunits of NISP, as well as the command and data management unit
(CDMU) of the spacecraft for telecommand and housekeeping management. We briefly review the main requirements
driving the design and the architecture of the software that is approaching the Critical Design Review level. The
interaction with the data processing unit (DPU), which is the intelligent subunit controlling the detector system, is
described in detail, as well as the concept for the implementation of the failure detection, isolation and recovery (FDIR)
algorithms. The first version of the software is under development on a Breadboard model produced by
AIRBUS/CRISA. We describe the results of the tests and the main performances and budgets.
KEYWORDS: Data storage, Near infrared, Computing systems, Data processing, Sensors, Data archive systems, Data modeling, Control systems, Databases, Data conversion
The NISP instrument on board the Euclid ESA mission will be developed and tested at different levels of integration
using various test equipment which shall be designed and procured through a collaborative and coordinated effort. The
NISP Instrument Workstation (NI-IWS) will be part of the EGSE configuration that will support the NISP AIV/AIT
activities from the NISP Warm Electronics level up to the launch of Euclid. One workstation is required for the NISP
EQM/AVM, and a second one for the NISP FM. Each workstation will follow the respective NISP model after delivery
to ESA for Payload and Satellite AIV/AIT and launch. At these levels the NI-IWS shall be configured as part of the
Payload EGSE, the System EGSE, and the Launch EGSE, respectively. After launch, the NI-IWS will be also re-used in
the Euclid Ground Segment in order to support the Commissioning and Performance Verification (CPV) phase, and for
troubleshooting purposes during the operational phase.
The NI-IWS is mainly aimed at the local storage in a suitable format of the NISP instrument data and metadata, at local
retrieval, processing and display of the stored data for on-line instrument assessment, and at the remote retrieval of the
stored data for off-line analysis on other computers.
We describe the design of the IWS software that will create a suitable interface to the external systems in each of the
various configurations envisaged at the different levels, and provide the capabilities required to monitor and verify the
instrument functionalities and performance throughout all phases of the NISP lifetime.
KEYWORDS: Control systems, Electronics, X-ray imaging, X-rays, Sensors, Interfaces, Space operations, X-rays, Control systems, Data compression, Signal detection, Field programmable gate arrays
Athena is one of L-class missions selected in the ESA Cosmic Vision 2015-2025 program for the science theme of the Hot and Energetic Universe. The Athena model payload includes the X-ray Integral Field Unit (X-IFU), an advanced actively shielded X-ray microcalorimeter spectrometer for high spectral resolution imaging, utilizing cooled Transition Edge Sensors. This paper describes the preliminary architecture of Instrument Control Unit (ICU), which is aimed at operating all XIFU’s subsystems, as well as at implementing the main functional interfaces of the instrument with the S/C control unit. The ICU functions include the TC/TM management with S/C, science data formatting and transmission to S/C Mass Memory, housekeeping data handling, time distribution for synchronous operations and the management of the X-IFU components (i.e. CryoCoolers, Filter Wheel, Detector Readout Electronics Event Processor, Power Distribution Unit). ICU functions baseline implementation for the phase-A study foresees the usage of standard and Space-qualified components from the heritage of past and current space missions (e.g. Gaia, Euclid), which currently encompasses Leon2/Leon3 based CPU board and standard Space-qualified interfaces for the exchange commands and data between ICU and X-IFU subsystems. Alternative architecture, arranged around a powerful PowerPC-based CPU, is also briefly presented, with the aim of endowing the system with enhanced hardware resources and processing power capability, for the handling of control and science data processing tasks not defined yet at this stage of the mission study.
KEYWORDS: Sensors, Space operations, Control systems, Electronics, Failure analysis, Calibration, Standards development, Space telescopes, Signal detection, Temperature sensors
In this paper we describe the main requirements driving the development of the Application software of the ICU of NISP, the Near-Infrared Spectro-Photometer of the Euclid mission. This software will be based on a real-time operating system and will interface with all the subunits of NISP, as well as the CMDU of the spacecraft for the Telecommand and Housekeeping management. We briefly detail the services (following the PUS standard) that will be made available, and also possible commonalities in the approach with the ASW of the VIS CDPU, which could make the development effort more efficient; this approach could also make easier the maintenance of the SW during the mission. The development plan of the ASW and the next milestones foreseen are described, together with the architectural design approach and the development environment we are setting up.
KEYWORDS: Data processing, Sensors, Data acquisition, Clocks, Control systems, Power supplies, Electronics, Interfaces, Photometry, Field programmable gate arrays
In this paper we describe the status of the development of the Data Processing Unit (DPU) of the Near-Infrared Spectro- Photometer (NISP) of the Euclid mission. The architecture of this unit is described, along with the Detector Control Unit (DCU), which operates the 16 HAWAII-2RG (H2RG), composing the NISP Focal Plane Array (FPA), by an equivalent number of SIDECAR systems. The design is evolved from the previous phases, with the implementation of a different approach in the data processing and consequently with the implementation of a large data buffer. The approach in implementing failure tolerance on this unit is described in detail; effort has been made to realize an architecture in which the impact of a single failure can be limited, in the worst case, to the loss of only one detector (out of 16). The main requirements driving the design are also described, in order to emphasize the most challenging areas and the foreseen solutions. The foreseen implementation of the on-board processing pipeline is also described, along with the basic interactions with the Instrument Control Unit (ICU) and with the Mass Memory Unit (MMU). Finally, we outline the on going activity for DPU/DCU bread-boarding.
The Euclid mission objective is to understand why the expansion of the Universe is accelerating by mapping the geometry of the dark Universe by
investigating the distance-redshift relationship and tracing the evolution of cosmic structures. The Euclid project is part of ESA's Cosmic Vision
program with its launch planned for 2020.
The NISP (Near Infrared Spectro-Photometer) is one of the two Euclid instruments and is operating in the near-IR spectral region (0.9-2μm) as a
photometer and spectrometer. The instrument is composed of:
- a cold (135K) optomechanical subsystem consisting of a SiC structure, an optical assembly (corrector and camera lens), a filter wheel mechanism, a
grism wheel mechanism, a calibration unit and a thermal control system
- a detection subsystem based on a mosaic of 16 Teledyne HAWAII2RG cooled to 95K with their front-end readout electronic cooled to 140K,
integrated on a mechanical focal plane structure made with Molybdenum and Aluminum. The detection subsystem is mounted on the optomechanical
subsystem structure
- a warm electronic subsystem (280K) composed of a data processing / detector control unit and of an instrument control unit that interfaces with the
spacecraft via a 1553 bus for command and control and via Spacewire links for science data
This presentation describes the architecture of the instrument at the end of the phase B (Preliminary Design Review), the expected performance, the
technological key challenges and preliminary test results obtained on a detection system demonstration model.
We discuss here the results of the interferometric observations with MIDI at VLTI of the peculiar symbiotic system HD330036. The interferometric data resolve a complex dust nebula with possibly a bipolar shape or an elongated disk structure inclined at ∼ 70° to the line of sight and oriented with the polar axis at PA ∼ −5°. By fitting to the visibility data a radiative transfer model of the system we obtain a good fit assuming a distance of ∼ 500 pc, at the lower end of the range found in literature.
KEYWORDS: Space operations, Calibration, System on a chip, Sensors, Control systems, Satellites, Mathematical modeling, Visible radiation, Seaborgium, Data processing
Euclid is the future ESA mission, mainly devoted to Cosmology. Like WMAP and Planck, it is a
survey mission, to be launched in 2019 and injected in orbit far away from the Earth, for a nominal
lifetime of 7 years. Euclid has two instruments on-board, the Visible Imager (VIS) and the Near-
Infrared Spectro-Photometer (NISP). The NISP instrument includes cryogenic mechanisms, active
thermal control, high-performance Data Processing Unit and requires periodic in-flight calibrations
and instrument parameters monitoring. To fully exploit the capability of the NISP, a careful control
of systematic effects is required. From previous experiments, we have built the concept of an
integrated instrument development and verification approach, where the scientific, instrument and
ground-segment expertise have strong interactions from the early phases of the project. In particular,
we discuss the strong integration of test and calibration activities with the Ground Segment, starting
from early pre-launch verification activities. We want to report here the expertise acquired by the
Euclid team in previous missions, only citing the literature for detailed reference, and indicate how it
is applied in the Euclid mission framework.
The Interferometric Stratospheric Astrometry for Solar system (ISAS) project is designed for high precision
astrometry on the brightest planets of the Solar System, with reference to many field stars, at the milli-arcsec
(mas) level or better. The science goal is the improvement on our knowledge of the dynamics of the Solar System,
complementing the Gaia observations of fainter objects. The technical goal is the validation of basic concepts for
the proposed Gamma Astrometric Measurement Experiment (GAME) space mission, in particular, combination
of Fizeau interferometry and coronagraphic techniques by means of pierced mirrors, intermediate angle dual field
astrometry, smart focal plane management for increased dynamic range and pointing correction. We discuss
the suitability of the stratospheric environment, close to space conditions, to the astrometric requirements. The
instrument concept is a multiple field, multiple aperture Fizeau interferometer, observing simultaneously four
fields, in order to improve on the available number of reference stars. Coronagraphic solutions are introduced
to allow observation of internal planets (Mercury and Venus), as well as of external planets over a large fraction
of their orbit, i.e. also close to conjunction with the Sun. We describe the science motivation, the proposed
experiment profile and the expected performance.
The Euclid mission objective is to map the geometry of the dark Universe by investigating the distance-redshift
relationship and the evolution of cosmic structures. The NISP (Near Infrared Spectro-Photometer) is one of the two
Euclid instruments operating in the near-IR spectral region (0.9-2μm). The instrument is composed of:
- a cold (140K) optomechanical subsystem constituted by a SiC structure, an optical assembly, a filter wheel
mechanism, a grism wheel mechanism, a calibration unit and a thermal control
- a detection subsystem based on a mosaic of 16 Teledyne HAWAII2RG 2.4μm. The detection subsystem is
mounted on the optomechanical subsystem structure
- a warm electronic subsystem (280K) composed of a data processing / detector control unit and of an
instrument control unit.
This presentation will describe the architecture of the instrument, the expected performance and the technological key
challenges. This paper is presented on behalf of the Euclid Consortium.
KEYWORDS: Calibration, Sensors, Interfaces, Data archive systems, Space operations, Satellites, Device simulation, Control systems, Data storage, Data acquisition
The Near Infrared Spectro-Photometer (NISP) on board the Euclid ESA mission will be developed and tested at various
levels of integration using various test equipment which shall be designed and procured through a collaborative and
coordinated effort.
In this paper we describe the Electrical Ground Support Equipment (EGSE) which shall be required to support the
assembly, integration, verification and testing (AIV/AIT) and calibration activities at instrument level before delivery to
ESA, and at satellite level, when the NISP instrument is mounted on the spacecraft.
We present the EGSE conceptual design as defined in order to be compliant with the AIV/AIT and calibration
requirements. The proposed concept is aimed at maximizing the re-use in the EGSE configuration of the Test Equipment
developed for subsystem level activities, as well as, at allowing a smooth transition from instrument level to satellite
level, and, possibly, at Ground Segment level.
This paper mainly reports the technical status at the end of the Definition phase and it is presented on behalf of the
Euclid Consortium.
The Near Infrared Spectrograph and Photometer (NISP) is one of the instruments on board the EUCLID mission.
The focal plane array (FPA) consists of 16 HAWAII-2RG HgCdTe detectors from Teledyne Imaging Scientific
(TIS), for NIR imaging in three bands (Y, J, H) and slitless spectroscopy in the range 0.9−2µm. Low total noise
measurements (i.e. total noise < 8 electrons) are achieved by operating the detectors in multiple non-destructive
readout mode for the implementation of both the Fowler and Up-The-Ramp (UTR) sampling, which also enables
the detection and removal of cosmic ray events. The large area of the NISP FPA and the limited satellite telemetry
available impose to perform the required data processing on board, during the observations. This requires a well
optimized on-board data processing pipeline, and high-performance control electronics, suited to cope with the
time constraints of the NISP acquisition sequences. This paper describes the architecture of the NISP on-board
electronics, which take charge of several tasks, including the driving of each individual HAWAII-2RG detectors
through their SIDECAR ASICs, the data processing, inclusive of compression and storage, and the instrument
control tasks. We describe the implementation of the processing power needed for the demanding on-board data
reduction. We also describe the basic operational modes that will be managed by the system during the mission,
along with data flow and the Telemetry/TeleCommands flow. This paper reports the NISP on-board electronics
architecture status at the end of the Phase B1, and it is presented on behalf of the Euclid Consortium.
In this paper we describe the thermal architecture of the Near Infrared Spectro-Photometer (NISP) on board the Euclid
ESA mission.
The instrument thermal design is based on the combination of two passive radiators coupled to cold space that, exploiting
the beneficial conditions of the L2 thermal environment, provide the temperature references for the main sub-systems.
One radiator serves as a 135K heat sink for the opto-mechanical structure and for the front-end cold electronics, while
working as an interception stage for the conductive parasitic heat leaks through struts and harness. The second, colder,
radiator provides a 95K reference for the instrument detectors. The thermal configuration has to ensure the units optimal
operating temperature needed to maximize instrument performance, adopting solutions consistent with the mechanical
specifications. At the same time the design has to be compliant with the stringent requirements on thermal stability of the
optical and detector units. The periodical perturbation of filter and grism wheel mechanisms together with orbital
variations and active loads instabilities make the temperature control one of the most critical issues of the whole design.
We report here the general thermal architecture at the end of the Definition Phase, together with the first analysis results
and preliminary performance predictions in terms of steady state and transient behavior. This paper is presented on
behalf of the Euclid Consortium.
KEYWORDS: Sensors, Computer simulations, Spectroscopy, Nondestructive evaluation, Signal processing, Data modeling, Image compression, Photometry, Data processing, Data compression
NISP is the near IR spectrophotometer instrument part of the Cosmic Vision Euclid mission. In this paper we describe an
end-to-end simulation scheme developed in the framework of the NISP design study to cover the expected focal-plane
on-board pre-processing operations. Non-destructive detector readouts are simulated for a number of different readout
strategies, taking into account scientific and calibration observations; resulting frames are passed through a series of
steps emulating the foreseen on-board pipeline, then compressed to give the final result. In order to verify final frame
quality and resulting computational and memory load, we tested this architecture on a number of hardware platforms
similar to those possible for the final NISP computing unit. Here we give the results of the latest tests. This paper mainly
reports the technical status at the end of the Definition Phase and it is presented on behalf of the Euclid Consortium.
GAME is a recent concept for a small/medium class mission aimed at Fundamental Physics tests in the Solar
system, by means of an optimised instrument in the visible, based on smart combination of coronagraphy and
Fizeau interferometry. The targeted precision on the γ and β parameters of the Parametrised Post-Newtonian
formulation of General Relativity are respectively in the 10-7-10-8 and 10-5-10-6 range, improving by one or two orders of magnitude with respect to the expectations on current or near future experiments. Such precision
is suitable to detect possible deviations from the unity value, associated to generalised Einstein models for
gravitation, with potentially huge impacts on the cosmological distribution of dark matter and dark energy from
a Solar system scale experiment. The measurement principle is based on the differential astrometric signature on
the stellar positions, i.e. based on the spatial component of the effect rather than the temporal component as in
the most recent experiments using radio link delay timing variation (Cassini). The instrument concept is based
on multiple field, multiple aperture Fizeau interferometry, observing simultaneously regions close to the Solar
limb (requiring the adoption of coronagraphic techniques), and others in opposition to the Sun. The diluted
optics approach is selected for achieving an efficient rejection of the scattered solar radiation, while retaining
an acceptable angular resolution on the science targets. The multiple field observation is aimed at cost-effective
control of systematic effects through simultaneous calibration. We describe the science motivation, the proposed
mission profile, the instrument concept and the expected performance.
KEYWORDS: Sensors, Particles, Monte Carlo methods, Space operations, Silicon, Radiation effects, Silicon carbide, Aluminum, Space telescopes, Computer simulations
One critical aspect in designing a space mission is the assessment of the level of radiation damage to the equipment that
one can expect during the course of the mission. The radiation environment in L2 orbit, however, has not been studied as
extensively as in the Low Earth Orbit case. Fluka is a Montecarlo software developed by CERN and INFN and
extensively used in high energy experimental physics and engineering, shielding, detector and telescope design, and
cosmic ray studies. In this paper, we make use of FLUKA to model the geometry of the structures surrounding the
detector, in order to analyze the mitigation strategy (i.e.: shielding of the detector assembly) in a well defined case (the
Euclid-NIS instrument, which is in its early design phase). By using a realistic cosmic ray spectrum and composition, we
analyze the resulting dose of ionizing and non-ionizing radiation on the Euclid-NIS detectors, and other effects.
A simulator of data frames produced by 'multi-accumulation' readout detectors has been developed during the feasibility
study for the NIS spectrograph, part of the European Euclid mission. The software can emulate various readout
strategies, allowing to compare the efficiency of different sampling techniques. Special care is given to two crucial
aspects: the minimization of the noise and the effects produced by cosmic hits.
The resulting readout noise is analyzed as a function of the background sources, detector native characteristics and
readout strategy, while the image deterioration by cosmic rays covers the simulation of hits and their correction
efficiency varying the readout modalities.
Simulated "multi-accumulation" frames, typical of multiplexer based detectors, are an ideal tool for testing the
efficiency of cosmic ray rejection techniques. In the present case cosmic rays are added to each raw frame conforming to
the rates and energy expected in the operational L2 region and in the chosen exposure time. Procedures efficiency for
cosmic ray identification and correction can also be easily tested in terms of memory occupancy and telemetry rates.
KEYWORDS: Sensors, Digital micromirror devices, Spectrographs, Head, Silicon carbide, Near infrared, Space telescopes, Cameras, Telescopes, Control systems
The ENIS wide-field spectrograph is part of the instrument package on board of the European space mission Euclid
devoted to map the dark universe and proposed for launch in 2017. ENIS will operate in the near-IR spectral region
(0.8-2 μm) and will provide in 4-5 years an accurate and extremely large survey of cosmological redshifts. The
instrument focal-plane is based on a combination of state of the art detectors light fed by a slitless spectrograph
allowing coverage and analysis of a high number of targets per cycle. During the feasibility study a spectrograph
option based on Digital Micromirror Device (DMD) programmable slits, allowing a significant increase in
instrumental sensitivity and accuracy, has also been examined. ENIS has been recently (Feb this year) pre-selected
for a phase-A study within a group of three medium class missions; final selection is foreseen for the end of next
year after a new phase of instrument revision.
A description of the work done during the feasibility-study phase for the ENIS focal-plane is here presented.
We present a new design of a four mirrors telescope for astrometric measurement to be used in the GAME
mission, currently under study at the Astronomical Observatory of Turin, Italy. The main aim of GAME -
Gamma Astrometric Measurement Experiment - is to measure the γ parameter of the Parameterized Post-
Newtonian formulation by looking at the deflection of light produced by the Sun's gravitational curvature, as in
the Dyson, Eddington et al. 1919 experiment, using a dedicated, space based dual-field telescope. A first design
has been presented in recent years, based on a Cassegrain scheme with a mask in front of the primary mirror to
realize multiple aperture Fizeau interferometry. The new design still implements a Fizeau interferometer, but the
telescope layout is based on a Korsch-like scheme with four conical mirrors, long focal length, and without the
use of exotic surfaces (aspheric or polynomial) as adopted in other long focal astrometric instruments. A different
combination scheme of the two lines of sight makes the dimensioning of the primary mirror more relaxed allowing
us to work with smaller surfaces and therefore to achieve a more compact payload configuration. The design
of the instrument and the masked interferometry approach allow us to maximize the astrometric performances
and at the same time to improve the baffling, minimizing the amount of stray light from the Sun. In this
paper we describe the mission profile, the observation principle, the new instrument layout and the expected
performances.
The Euclid Near-Infrared Spectrometer (E-NIS) Instrument was conceived as the spectroscopic probe on-board the ESA
Dark Energy Mission Euclid. Together with the Euclid Imaging Channel (EIC) in its Visible (VIS) and Near Infrared
(NIP) declinations, NIS formed part of the Euclid Mission Concept derived in assessment phase and submitted to the
Cosmic Vision Down-selection process from which emerged selected and with extremely high ranking. The Definition
phase, started a few months ago, is currently examining a substantial re-arrangement of the payload configuration due to
technical and programmatic aspects. This paper presents the general lines of the assessment phase payload concept on
which the positive down-selection judgments have been based.
KEYWORDS: Sun, Stars, General relativity, Solar processes, Aerospace engineering, Current controlled current source, Precision measurement, Berkelium, Telescopes, Satellites
The GAME mission concept is aimed at very precise measurement
of the gravitational deflection of light by the Sun, by an
optimized telescope in the visible and launched in orbit
on a small class satellite. The targeted precision on the γ parameter of the Parametrized Post-Newtonian formulation of General Relativity is 10-6 or better, i.e. one to two orders of magnitude better than the best current results. Such precision is suitable to detect possible deviations from unity value, associated to generalized Einstein models for gravitation, with potentially huge impacts on the cosmological distribution of dark matter and dark energy.
The measurement principle is based on differential astrometric
signature on the stellar positions, i.e. on the spatial component
of the effect rather than the temporal component as in recent
experiments using radio link delay timing. Exploiting the observation strategy, it is also possible to target other interesting scientific goals both in the realm of General Relativity and in the observations of extrasolar systems. The instrument is a dual field, multiple aperture Fizeau interferometer, observing simultaneously two regions close to the Solar limb. The diluted optics approach is selected for efficient rejection of the solar radiation, while retaining an acceptable angular resolution on the science targets.
We describe the science motivation, the proposed mission profile, the payload concept and the expected performance from recent results.
In this paper we present the status of different experiments set up at Turin Observatory on novel techniques
for multiple beam combination, adopting mostly bulk optics. The goal of these experiments is to find the
best scheme able to perform efficient fringe tracking operation on a densely populated (N>4) interferometer,
while at the same time maximizing optical throughput and sensitivity on faint sources. One of these concepts
has been proposed for the VSI fringe tracker (see Corcione et al, this conference). The schemes proposed
have also the advantage of being in principle easily adapted to a large number of beams.
The implementation of the simultaneous combination of several telescopes (from four to eight) available at
Very Large Telescope Interferometer (VLTI) will allow the new generation interferometric instrumentation
to achieve interferometric image synthesis with unprecedented resolution and efficiency. The VLTI Spectro
Imager (VSI) is the proposed second-generation near-infrared
multi-beam instrument for the Very Large
Telescope Interferometer, featuring three band operations (J, H and K), high angular resolutions (down to
1.1 milliarcsecond) and high spectral resolutions. VSI will be equipped with its own internal Fringe Tracker
(FT), which will measure and compensate the atmospheric perturbations to the relative beam phase, and in
turn will provide stable and prolonged observing conditions down to the magnitude K=13 for the scientific
combiner. In its baseline configuration, VSI FT is designed to implement, from the very start, the minimum
redundancy combination in a nearest neighbor scheme of six telescopes over six baselines, thus offering better options for rejection of large intensity or phase fluctuations over each beam, due to the symmetric set-up.
The planar geometry solution of the FT beam combiner is devised to be easily scalable either to four or eight
telescopes, in accordance to the three phase development considered for VSI. The proposed design, based
on minimum redundancy combination and bulk optics solution, is described in terms of opto-mechanical
concept, performance and key operational aspects.
The VLTI Spectro Imager project aims to perform imaging with a temporal resolution of 1 night and with a maximum
angular resolution of 1 milliarcsecond, making best use of the Very Large Telescope Interferometer capabilities. To
fulfill the scientific goals (see Garcia et. al.), the system requirements are: a) combining 4 to 6 beams; b) working in
spectral bands J, H and K; c) spectral resolution from R= 100 to 12000; and d) internal fringe tracking on-axis, or off-axis
when associated to the PRIMA dual-beam facility.
The concept of VSI consists on 6 sub-systems: a common path distributing the light between the fringe tracker and the
scientific instrument, the fringe tracker ensuring the co-phasing of the array, the scientific instrument delivering the
interferometric observables and a calibration tool providing sources for internal alignment and interferometric
calibrations. The two remaining sub-systems are the control system and the observation support software dedicated to the
reduction of the interferometric data.
This paper presents the global concept of VSI science path including the common path, the scientific instrument and the
calibration tool. The scientific combination using a set of integrated optics multi-way beam combiners to provide high-stability
visibility and closure phase measurements are also described. Finally we will address the performance budget of
the global VSI instrument. The fringe tracker and scientific spectrograph will be shortly described.
KEYWORDS: Telescopes, Stars, Spectral resolution, Spatial resolution, Interferometry, Integrated optics, Space telescopes, Visibility, Image restoration, Signal to noise ratio
The VLTI Spectro Imager (VSI) was proposed as a second-generation instrument of the Very Large Telescope Interferometer
providing the ESO community with spectrally-resolved, near-infrared images at angular resolutions
down to 1.1 milliarcsecond and spectral resolutions up to R = 12000. Targets as faint as K = 13 will be imaged
without requiring a brighter nearby reference object; fainter targets can be accessed if a suitable reference is
available. The unique combination of high-dynamic-range imaging at high angular resolution and high spectral
resolution enables a scientific program which serves a broad user community and at the same time provides the
opportunity for breakthroughs in many areas of astrophysics. The high level specifications of the instrument are
derived from a detailed science case based on the capability to obtain, for the first time, milliarcsecond-resolution
images of a wide range of targets including: probing the initial conditions for planet formation in the AU-scale
environments of young stars; imaging convective cells and other phenomena on the surfaces of stars; mapping
the chemical and physical environments of evolved stars, stellar remnants, and stellar winds; and disentangling the central regions of active galactic nuclei and supermassive black holes. VSI will provide these new capabilities
using technologies which have been extensively tested in the past and VSI requires little in terms of new
infrastructure on the VLTI. At the same time, VSI will be able to make maximum use of new infrastructure as it
becomes available; for example, by combining 4, 6 and eventually 8 telescopes, enabling rapid imaging through
the measurement of up to 28 visibilities in every wavelength channel within a few minutes. The current studies
are focused on a 4-telescope version with an upgrade to a 6-telescope one. The instrument contains its own
fringe tracker and tip-tilt control in order to reduce the constraints on the VLTI infrastructure and maximize
the scientific return.
The GAME mission concept aims at the very precise measurement of the gravitational deflection of light by the
Sun, by means of an optimised telescope operating in the visible and launched in orbit on a small class satellite.
The targeted precision on the γ parameter of the Parametrised Post-Newtonian formulation of General Relativity
is 10-6 or better, i.e. one to two orders of magnitude better than the best currently available results. Such
precision is suitable to detect possible deviations from the unity value, associated to generalised Einstein models
for gravitation, with potentially huge impacts on the cosmological distribution of dark matter and dark energy.
The measurement principle is based on the differential astrometric signature on the stellar positions, i.e., based
on the spatial component of the effect rather than the temporal component as in the most recent experiments
using radio link delay timing. The observation strategy also allows some additional scientific objectives related
to other tests of General Relativity and to the study of exo-planetary field, multiple aperture Fizeau interferometer, observing simultaneously two regions close to the Solar
limb. The diluted optics approach is selected for achieving an efficient rejection of the scattered solar radiation,
while retaining an acceptable angular resolution on the science targets. We describe the science motivation, the
proposed mission profile, the possible payload implementation and the expected performance.
In this paper we present an overview of the construction and implementation of the unmodulated infrared pyramid wavefront sensor PYRAMIR at the Calar Alto 3.5 m telescope. PYRAMIR is an extension of the existing visible Shack-Hartmann adaptive optics system ALFA, which allows wavefront sensing in the near-infrared wavefront regime. We describe the optical setup and the calibration procedure of the pyramid wavefront sensor. We discuss possible drawbacks of the calibration and show the results gained on Calar Alto.
On the way to the Extremely Large Telescopes (ELT) the Large Binocular
Telescope (LBT) is an intermediate step. The two 8.4m mirrors create a masked aperture of 23m. LINC-NIRVANA is an instrument taking advantage of this opportunity. It will get, by means of Multi-Conjugated Adaptive Optics (MCAO), a moderate Strehl Ratio over a 2 arcmin field of view, which is used for Fizeau (imaging) interferometry in J,H and K. Several MCAO concepts, which are
proposed for ELTs, will be proven with this instrument. Studies of sub-systems are done in the laboratory and the option to test them on sky are kept open. We will show the implementation of the MCAO concepts and control aspects of the instrument and present the road map to the final installation at LBT. Major milestones of LINC-NIRVANA, like preliminary design review or final design review are already done or in preparation. LINC-NIRVANA is one of the
few MCAO instruments in the world which will see first light and go into operation within the next years.
We present in this paper the results of laboratory tests on the detector system for PYRAMIR, the infrared wavefront sensor for ALFA, the Adaptive Optics system at Calar Alto Observatory. PYRAMIR will use, at least in a first phase, a Hawaii-I detector, with 4 512x512 pixels2 quadrants which are read-out in parallel on 4 independent output channels. Since wavefront sensing in the infrared requires high frame rates and since the signal of the pyramid
wavefront sensor is distributed on a small fraction of the detector area, the detector is operated in a windowed mode. Setting the
pixel clock to the fastest speed supported by the chip without a significant increase in read noise and by addressing a 64x64 window, for instance, we are able to reach frame rates in excess of 150 Hz. We show our measurements of total read noise obtained at this relatively high read-out speed, as well as the results of our tests concerning linearity and sensitivity. The results show that
the noise introduced by the read-out electronics itself is negligible compared with the intrinsic read-noise of the detector.
In order to maximize the read-out efficiency we use differential measurements on a sequence of non destructive read-outs. We discuss the main characteristics of the detector when operating in this mode.
LINC-NIRVANA is an imaging interferometer for the Large Binocular Telescope (LBT) and will make use of multi-conjugated adaptive optics (MCAO) with two 349 actuators deformable mirrors (DM), two 672 actuator deformable secondary mirrors and a total of 4 wavefront sensors (WFS) by using 8 or 12 natural guide stars each. The goal of the MCAO is to increase sky coverage and achieve a medium Strehl-ratio over the 2 arcmin field of view. To test the concepts and prototypes, a laboratory setup of one MCAO arm is being built. We present the layout of the MCAO prototype, planned and accomplished tests, especially for the used Xinetics DMs, and a possible setup for a test on sky with an existing 8m class telescope.
LUCIFER (LBT NIR Spectrograph Utility with Camera and Integral-Field
Unit for Extragalactic Research) is a NIR spectrograph and imager for
the LBT (Large Binocular Telescope) working in the wavelength range from 0.9 to 2.5 microns. The instrument is to be built by a consortium of five german institutes (Landessternwarte Heidelberg (LSW), Max Planck Institut for Astronomy (MPIA), Max Planck Institut for Extraterrestric Physics (MPE), Astronomical Institut of the Ruhr-University Bochum (AIRUB) and Fachhochschule for Technics and Design Mannheim (FHTG)). LUCIFER will be one of the first light instruments of the LBT and will be available to the community at the end of 2005. A copy of the instrument for the second LBT mirror follows about one year later.
The paper presents a brief status report of the procured and built
hardware, of the workpackages already carried out and summarizes the ongoing work in progress.
KEYWORDS: Sensors, Electronics, Signal detection, Signal to noise ratio, Control systems, Digital signal processing, Amplifiers, Process control, Signal processing, Clocks
We describe the detector subsystem developed at MPIA to operate the Rockwell Hawaii-2 detectors used in the LUCIFER and LINC-NIRVANA instruments for the Large Binocular Telescope (LBT). To fully exploit the capabilities of the LBT, the detector subsystem must meet, especially in the case of the low background applications foreseen for LUCIFER, very stringent requirements in terms of stability and read noise. A read-out electronics has been developed at MPIA, which is able to read the 32 outputs of the Hawaii-2 detector, as well as the 4 reference signals available in this chip. The noise figure associated to the electronics alone is negligible with respect to the intrinsic read noise of the detector, while the cloking patterns and the value of the bias voltages applied to the chip are optimized in order to maximize the signal to noise ratio
in the different operating modes. We present the results of the tests performed with the LUCIFER science detector; in particular, we
describe the main properties of the detector: read noise, dark current, linearity, and long term stability, and what are the read-out schemes foreseen for different observational modes. We discuss also how the reference outputs can be used in order to correct for thermal drifts, and how effective those outputs are in removing higher frequency noise components.
LINC-NIRVANA is a Fizeau interferometer which will be built for the Large Binocular Telescope (LBT). The LBT exists of two 8.4m mirrors on one mounting with a distance of 22.8m between the outer edges of the two mirrors. The interferometric technique used in LINC-NIRVANA provides direct imaging with the resolution of a 23m telescope in one direction and 8.4m in the other. The instrument uses multi-conjugated adaptive optics (MCAO) to increase the sky coverage and achieve the diffraction limit in J, H, K over a moderate Field of View (2 arcmin in diameter). During the preliminary design phase the team faced several problems similar to those for an instrument at a 23m telescope. We will give an overview of the current design, explain problems related to 20m class telescopes and present solutions.
The mid-infrared interferometric instrument MIDI is currently undergoing testing in preparation for commissioning on the Very Large Telescope Interferometer VLTI at the end of this year 2002. It will perform interferometric observations over the 8 μm - 13 μm wavelength range, with a spatial resolution of 20 milliarcsec, a spectral resolution of up to 250, and an anticipated point source sensitivity of N = 4 mag or 1 Jy for self-fringe tracking, which will be the only observing mode during the first months of operation. We describe the layout of the instrument and the performance during laboratory tests, both for broadband and spectrally resolved observing modes. We also briefly outline the planned guaranteed time observations.
KEYWORDS: Sensors, Interferometry, Clocks, Electronics, Digital signal processing, Mid-IR, Signal detection, Control systems, Signal processing, Data conversion
Interferometric observations at 10 micron combine the difficulties of the relatively new interferometric techniques with the problems of overcoming the strong and highly variable thermal background which are typical of thermal infrared observations. In particular, the detector subsystem must comply to strict requirements in terms of stability, of read noise, and of read out speed. Here we present the results obtained during laboratory test of MIDI, the Mid-IR interferometric instrument for VLTI. We selected as detector for the MIDI instrument a Raytheon 320x240 IBC array. We will discuss some of the aspects of the foreseen operation of MIDI, and the methods adopted to implement those on our detector system. We will show our results on detector stability, on its performances (in particular Quantum efficiency and read-out noise), and on the reaction to high fluxes. By using the possibility of hardware windowing, frame times of the order of 2 ms can be reached. Finally, we will show the characteristics of the detector when used in interferometric mode during tests of the whole MIDI instrument with both monochromatic and broad band calibration sources.
In this paper we present the results of the first tests performed at MPIA on the detector system of MIDI, the Mid-IR interferometric instrument for VLTI. Interferometric observations at 10 micrometers , while having advantages with respect to near-IR and optical wavelengths in terms of seeing and coherence time, must face the problem of the strong thermal background coming from the telescope and from the sky. In order to reach background limited performances in the observing conditions foreseen for MIDI at Paranal, the detector and the associated read-out electronics must comply to strict requirements. The different MIDI observing modes are characterized by widely different values of background per pixel; in high background conditions the main problem is to avoid saturation, while in medium-background conditions we are close to read-out noise limited conditions. Therefore, large integration capacity and high speed must be reached with low read-out noise. The read-out electronic chain is described; at maximum speed, one full 16-bit 320 X 240 pixels2 frame can be read in 3.6 msec. Since only a portion of the detector's field of view will contain useful information, only selected parts of the detector will be read, thus increasing the frame rate. We briefly review the different read-out strategies adopted; the correspondent operations on the detector are described. We also present the results of the first tests performed at MPIA on the whole detector subsystem, using a bare multiplexer of the selected detector (a 320 X 240 Si:As IBC array from Raytheon Corp.).
We describe principles, design and present status of MIDI, the mid-infrared interferometric instrument for the VLTI, which is planned to come into operation at the ESO Very Large Telescope Interferometer during the second half of 2001.
KEYWORDS: Telescopes, Sensors, Cameras, Infrared cameras, Data acquisition, Electronics, Digital signal processing, Control systems, Channel projecting optics, Infrared telescopes
Following the availability on the market of IR arrays able to perform ground-based astronomical observations in the atmospheric windows longward of 2.5 micrometers , we started at the Torino Astronomical Observatory a new project aimed at the construction of a thermal IR camera to be installed at the TIRGO telescope. Located in the Swiss alps at 3100 m a.s.l., this Italian facility (1.5 m f/20 IR optimized) provides during the winter months a relatively high number of nights (20%) with first-rate conditions (low temperature and emissivity) for medium-IR observations. In order to fully exploit this potential, we designed an instrument, named Two-Channel Medium IR Camera (TC-MIRC) operating over the entire 1 to 14 micrometers region and optimized for the 2.5 to 14 micrometers thermal bands. TC-MIRC covers such a broad range of wavelengths using two IR array detectors: an InSb device for the 1 to 5 micrometers region and a Si:Ga device for the 8 to 14 micrometers band. The main characteristic of the camera is that both arrays can simultaneously observe the same region. In this way, we can not only approach an almost double observing efficiency (time really spent `on target'), but also use both detectors for correlated observations and testing of unconventional acquisition techniques. It follows that TC-MIRC is a complex instrument presenting several interesting features. Thanks to the presence of two independent optical channels, the user can change the filters, adjust the focus and vary the optical scale on a channel without affecting the acquisition running on the other array. In particular, the possibility of adjusting the optical scale on each detector during the observations allows the user to select the most convenient sampling and field of view on the basis of the actual seeing or diffraction conditions, background level and scientific needs. Moreover, the adopted cryogenic system is entirely based on a mechanical closed-cycle cooler and allows very low-cost operations and easy maintenance on the mountain for long periods of time. In this paper we present the opto/mechanical design and construction, the general structure of the control system and the software architecture. We report the performances reached by the most critical parts of the instrument during the test carried out in the laboratory and at the telescope during the first engineering run in January 1994.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.