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.
R. Laureijs, R. Vavrek, G. Racca, R. Kohley, P. Ferruit, V. Pettorino, T. Bönke, A. Calvi, L. Gaspar Venancio, L. Campos, E. Maiorano, O. Piersanti, S. Prezelus, U. Ragnit, P. Rosato, C. Rosso, H. Rozemeijer, A. Short, P. Strada, D. Stramaccioni, M. Szafraniec, B. Altieri, G. Buenadicha, X. Dupac, P. Gómez Cambronero, K. Henares Vilaboa, C. Hernandez de la Torre, J. Hoar, M. Lopez-Caniego Alcarria, P. Marcos Arenal, J. Martin Fleitas, M. Miluzio, A. Mora, S. Nieto, R. Perez Bonilla, P. Teodoro Idiago, F. Cordero, J. Mendes, F. Renk, A. Rudolph, M. Schmidt, J. Schwartz, Y. Mellier, H. Aussel, M. Berthé, P. Casenove, M. Cropper, J. Cuillandre, J. Dinis, A. Gregorio, K. Kuijken, T. Maciaszek, L. Miller, R. Scaramella, M. Schirmer, I. Tereno, A. Zacchei, S. Awan, G. Candini, P. Liebing, R. Nakajima, S. Dusini, P. Battaglia, E. Medinaceli, C. Sirignano, I. Baldry, C. Baugh, F. Bernardeau, F. Castander, A. Cimatti, W. Gillard, L. Guzzo, H. Hoekstra, K. Jahnke, T. Kitching, E. Martin, J. Mohr, W. Percival, J. Rhodes
During its 6-year nominal mission, Euclid shall survey one third of the sky, enabling us to examine the spatial distributions of dark and luminous matter during the past 10 Gyr of cosmic history. The Euclid satellite was successfully launched on a SpaceX Falcon 9 launcher from Cape Canaveral on 1 July 2023 and is fully operational in a halo orbit around the Second Sun-Earth Lagrange point. We present an overview of the expected and unexpected findings during the early phases of the mission, in the context of technological heritage and lessons learnt. The first months of the mission were dedicated to the commissioning of the spacecraft, telescope and instruments, followed by a phase to verify the scientific performance and to carry out the in-orbit calibrations. We report that the key enabling scientific elements, the 1.2-meter telescope and the two scientific instruments, a visual imager (VIS) and a near-infrared spectrometer and photometer (NISP), show an inorbit performance in line with the expectations from ground tests. The scientific analysis of the observations from the Early Release Observations (ERO) program done before the start of the nominal mission showed sensitivities better than the prelaunch requirements. The nominal mission started in December 2023, and we allocated a 6-month early survey operations phase to closely monitor the performance of the sky survey. We conclude with an outlook of the activities for the remaining mission in the light of the in-orbit performance.
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).
LiteBIRD, the Lite (Light) satellite for the study of B-mode polarization and Inflation from cosmic background Radiation Detection, is a space mission for primordial cosmology and fundamental physics. JAXA selected LiteBIRD in May 2019 as a strategic large-class (L-class) mission, with its expected launch in the late 2020s using JAXA's H3 rocket. LiteBIRD plans to map the cosmic microwave background (CMB) polarization over the full sky with unprecedented precision. Its main scientific objective is to carry out a definitive search for the signal from cosmic inflation, either making a discovery or ruling out well-motivated inflationary models. The measurements of LiteBIRD will also provide us with an insight into the quantum nature of gravity and other new physics beyond the standard models of particle physics and cosmology. To this end, LiteBIRD will perform full-sky surveys for three years at the Sun-Earth Lagrangian point L2 for 15 frequency bands between 34 and 448 GHz with three telescopes, to achieve a total sensitivity of 2.16 μK-arcmin with a typical angular resolution of 0.5° at 100 GHz. We provide an overview of the LiteBIRD project, including scientific objectives, mission requirements, top-level system requirements, operation concept, and expected scientific outcomes.
LiteBIRD has been selected as JAXA’s strategic large mission in the 2020s, to observe the cosmic microwave background (CMB) B-mode polarization over the full sky at large angular scales. The challenges of LiteBIRD are the wide field-of-view (FoV) and broadband capabilities of millimeter-wave polarization measurements, which are derived from the system requirements. The possible paths of stray light increase with a wider FoV and the far sidelobe knowledge of -56 dB is a challenging optical requirement. A crossed-Dragone configuration was chosen for the low frequency telescope (LFT : 34–161 GHz), one of LiteBIRD’s onboard telescopes. It has a wide field-of-view (18° x 9°) with an aperture of 400 mm in diameter, corresponding to an angular resolution of about 30 arcminutes around 100 GHz. The focal ratio f/3.0 and the crossing angle of the optical axes of 90◦ are chosen after an extensive study of the stray light. The primary and secondary reflectors have rectangular shapes with serrations to reduce the diffraction pattern from the edges of the mirrors. The reflectors and structure are made of aluminum to proportionally contract from warm down to the operating temperature at 5 K. A 1/4 scaled model of the LFT has been developed to validate the wide field-of-view design and to demonstrate the reduced far sidelobes. A polarization modulation unit (PMU), realized with a half-wave plate (HWP) is placed in front of the aperture stop, the entrance pupil of this system. A large focal plane with approximately 1000 AlMn TES detectors and frequency multiplexing SQUID amplifiers is cooled to 100 mK. The lens and sinuous antennas have broadband capability. Performance specifications of the LFT and an outline of the proposed verification plan are presented.
LiteBIRD is a JAXA-led Strategic Large-Class mission designed to search for the existence of the primordial gravitational waves produced during the inflationary phase of the Universe, through the measurements of their imprint onto the polarization of the cosmic microwave background (CMB). These measurements, requiring unprecedented sensitivity, will be performed over the full sky, at large angular scales, and over 15 frequency bands from 34 GHz to 448 GHz. The LiteBIRD instruments consist of three telescopes, namely the Low-, Medium-and High-Frequency Telescope (respectively LFT, MFT and HFT). We present in this paper an overview of the design of the Medium-Frequency Telescope (89{224 GHz) and the High-Frequency Telescope (166{448 GHz), the so-called MHFT, under European responsibility, which are two cryogenic refractive telescopes cooled down to 5 K. They include a continuous rotating half-wave plate as the first optical element, two high-density polyethylene (HDPE) lenses and more than three thousand transition-edge sensor (TES) detectors cooled to 100 mK. We provide an overview of the concept design and the remaining specific challenges that we have to face in order to achieve the scientific goals of LiteBIRD.
Euclid, an ESA mission designed to characterise dark energy and dark matter, passed its Mission Critical Design Review in November 2018. It was demonstrated that the project is ready to start integration and test of the main systems, and that it has the ability to fulfil its top-level mission requirements. In addition, based on the performances at M-CDR, the scientific community has verified that the science requirements can be achieved for the Weak Lensing and Galaxy Clustering dark energy probes, namely a dark energy Figure of Merit of 400 and a 2% accuracy in the growth factor exponent gamma. We present the status of the main elements of the Euclid mission in the light of the demanding high optical performance which is the essential design driver is the to meet the scientific requirements. We include the space segment comprising of a service module and payload module hosting the telescope and its two scientific instruments, and the ground segment, which encompasses the operational and science ground segment. The elements for the scientific success of the mission for a timely release of the data are shortly presented: the processing and calibration of the data, and the design of the sky survey. Euclid is presently on schedule for a launch in September 2022.
The Laboratoire d’Astrophysique de Marseille (LAM) is deeply involved in the development and the test of the NISP (Near Infrared Spectro-Photometer) instrument for the ESA EUCLID mission that will be launched in 2020. The goal of the mission is to understand the nature of the dark energy responsible for the accelerating expansion of the Universe. NISP is one of its two instruments operating in the near-IR spectral region (0.9-2μm) to map the geometry of the dark Universe. The integration of the NISP flight model (FM) has been started at LAM to allow its delivery in 2019 to the payload after vibration test and two thermal vacuum test campaigns to demonstrate the performance of the instrument. The thermal vacuum test will take place in ERIOS chamber, a 90m3 chamber developed by LAM to test optical instruments at cryogenics temperature and high vacuum. In addition to the chamber, a full and specialised set of ground support equipment called the Verification Ground System (VGS) is developed to fill the goal of the NISP test campaign. The test campaign combines functional tests of the detectors and wheels, performance tests of the instrument, calibration procedure validation and observations scenario test, all done at LAM. One of the main objectives of the test campaign is the measurement of NISP focus position with respect to the EUCLID object plane. The VGS is made of i) a telescope simulator to simulate the EUCLID telescope for optical performance tests, ii) a thermal environment to simulate the Euclid PLM thermal interfaces, iii) the NISP Electrical GSE (EGSE) to control the instrument during the test and iv) a Metrology Verification System (MVS) to measure the positions of NISP and the telescope simulator during the test. We present the set of GSE developed for NISP and their performance already validated during two blank tests: thermal blank test and metrology blank test. In addition, a blank test with all the VGS parts (thermal, optical, metrology) is scheduled in the coming months to validate the overall performance of this GSE including the telescope simulator. The goal is to measure with a high precision the focus distance of the telescope simulator at cold and the stability of the focus in time, and to demonstrate the functionality of the telescope simulator for NISP test campaign needs. Finally, we describe the thermal vacuum test configuration for the “end to end” test on the NISP flight model foreseen by beginning of 2019.
In space, cooling down Infra Red detectors and optics to cryogenic temperature raises always the same issue : what is the best way to manage simultaneously thermal cooling, stability, mechanical discoupling and accurate focal plane components location, in a lightweight and compact solution? The passive cryocooler developed by Alcatel SPace Industries under CNES contract in the frame of the IASI instrument (Infrared Atmospheric Sounding Interferometer), offers an efficient solution for 90K to 100K temperature levels. We intend you to present the architecture and performance validation plan of the CBS.
KEYWORDS: Sensors, Staring arrays, Diffusers, Scanning tunneling microscopy, Interferometers, Astronomical imaging, Digital holography, Gas lasers, Long wavelength infrared, Temperature metrology
Euclid is a part of the European Space Agency Cosmic Vision program. Euclid mission’s goal is to understand the origin of the accelerating expansion of the Universe. This space mission will embark a 1.2 m Korsch telescope, a visible imager (VIS) and a near-infrared spectrometer and photometer (NISP).
EUCLID mission [1] has been selected by ESA in 2012 in the context of the Cosmic Vision program to
understand the nature of the dark energy and the dark matter. It is designed to map the geometry of the dark
Universe by investigating the distance-redshift relationship and the evolution of cosmic structures.
We present digital holographic interferometry (DHI) in the long-wave infrared for monitoring the deformation under cryogenic conditions of a segmented focal plane array to be used in a space mission. The long wavelength was chosen for its ability to allow measurement of displacements 20 times larger than DHI in the visible, which were foreseen with the test object under large temperature variations. The latter is a mosaic of 4×4 detectors assembled on a frame. DHI was required to assess the global deformation of the assembly, the deformation of each detector, and out-of-plane movements of each of them with respect to their neighbors. For that reason, we incorporated the temporal phase unwrapping by capturing a sufficiently high number of holograms between which the phase does not undergo large variations. At last, since the specimen exhibits specular reflectivity at that wavelength, it is illuminated by means of a reflective diffuser.
The ESA mission Euclid is designed to explore the dark side of the Universe. The NISP (Near Infrared Spectro-
Photometer) is one of its two instruments operating in the near-IR spectral region (0.9-2μm), that will be fully integrated
and tested at Laboratory d’Astrophysique de Marseille (LAM) under vacuum and thermal conditions. The test campaign
will regroup functional tests, performance tests, calibration procedure validation and observations scenario test. One of
the main objectives of the test campaign will be the measurement of the focus position of NISP with respect to the
EUCLID object plane. To achieve these tests campaign, a global Ground Support Equipment (GSE) called the
Verification Ground System (VGS) has to be developed. It will be a complex set of GSE integrated in ERIOS chamber
made of: a telescope simulator to simulate the EUCLID telescope and to inject light into NISP, a thermal environment to
be used for NISP thermal balance and verification, a sets of mechanical interfaces to align all the parts into ERIOS
chamber, the NISP Electrical GSE (EGSE) to control the instrument during the test and a metrology system to measure
the positions of the components during the test. We will present the preliminary design and concepts of the VGS and we
will show the main difficulties we have to deal with: design of thermal environment at 80K with 4mK stability, the
development of a metrology system in vacuum, knowledge of the focus position within 150μm in cold, etc. The main
objectives of the NISP test will be explained and how the VGS responds to the test requirement.
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).
Cleanliness specifications for infrared detector arrays are usually so stringent that effects are neglibile. However, the specifications determine only the level of particulates and areal density of molecular layer on the surface, but the chemical composition of these contaminants are not specified. Here, we use a model to assess the impact on system quantum efficiency from possible contaminants that could accidentally transfer or cryopump to the detector during instrument or spacecraft testing and on orbit operation. Contaminant layers thin enough to meet typical specifications, < 0.5μgram/cm2, have a negligible effect on the net quantum efficiency of the detector, provided that the contaminant does not react with the detector surface, Performance impacts from these contaminant plating onto the surface become important for thicknesses 5 - 50μgram/cm2. Importantly, detectable change in the ”ripple” of the anti reflection coating occurs at these coverages and can enhance the system quantum efficiency. This is a factor 10 less coverage for which loss from molecular absorption lines is important. Thus, should contamination be suspected during instrument test or flight, detailed modelling of the layer on the detector and response to very well known calibrations sources would be useful to determine the impact on detector performance.
Euclid mission is designed to understand the dark sector of the universe. Precise redshift measurements are provided by H2RG detectors. We propose an unbiased method of fitting the flux with Poisson distributed and correlated data, which has an analytic solution and provides a reliable quality factor - fundamental features to ensure the goals of the mission. We compare our method to other techniques of signal estimation and illustrate the anomaly detection on the flight-like detectors. Although our discussion is focused on Euclid NISP instrument, much of what is discussed will be of interest to any mission using similar near-infrared sensors.
Euclid, a major ESA mission for the study of dark energy, will offer a large survey of tens of millions of galaxies thanks to its Near-Infrared Spectro-Photometer. For it to be successful, the 16 Teledyne's 2.3 μm cutoff 2048x2048 pixels IR HgCdTe detectors of the focal plane must show very high performances over more than 95% of pixels, in terms of median dark current, total noise, budget error on non-linearity after correction, residual dark due to latency effects and quantum efficiency. This will be verified through a thorough characterization of their performances, leading to the production of the pixel map calibration database for the Euclid mission. Characterization is challenging in many ways: each detector will have to be fully and accurately characterized in less than three weeks, with rather tight requirements: dark current at the 10-3 e-/s level with 10% accuracy, relative Pixel Response map better than 1%, obtained with an illumination flatness better than 1%, measurements alternating dark and high level illumination taking care of latency impacts. Due to statistics needs, very long runs (24h without interrupts) of scripted measurements would be executed. Systematics of the test bench should be at the end the limiting factor of the parameter measurement accuracy. Test plan, facilities with functionalities developed for those specific purposes and associated performances will be described.
In the scope of EUCLID spatial mission, NISP instrument requires high positioning accuracy and high dimensional stability to achieve the required optical performances. LAM is in charge of the development of the instrument main structure which is based on silicon carbide material technology and allows the accurate positioning and maintain of the optomechanical concept sub-systems. This article presents the main steps of this development. It describes the challenging design of this mechanical concept. The associated finite element model, demonstrating the thermomechanical strength of the structure, is presented. Spatial environment vibrations tests performed on the hardware are explained and detailed: requirements, instrumentation and test methodology with the introduction of notching. Finally, the correlation study between finite element analyses and tests is exposed.
KEYWORDS: Data processing, Galactic astronomy, Space operations, Telescopes, Point spread functions, K band, Sensors, Image quality, Data archive systems, Calibration
Euclid is a space-based optical/near-infrared survey mission of the European Space Agency (ESA) to investigate the
nature of dark energy, dark matter and gravity by observing the geometry of the Universe and on the formation of
structures over cosmological timescales. Euclid will use two probes of the signature of dark matter and energy: Weak
gravitational Lensing, which requires the measurement of the shape and photometric redshifts of distant galaxies, and
Galaxy Clustering, based on the measurement of the 3-dimensional distribution of galaxies through their spectroscopic
redshifts. The mission is scheduled for launch in 2020 and is designed for 6 years of nominal survey operations. The
Euclid Spacecraft is composed of a Service Module and a Payload Module. The Service Module comprises all the
conventional spacecraft subsystems, the instruments warm electronics units, the sun shield and the solar arrays. In
particular the Service Module provides the extremely challenging pointing accuracy required by the scientific objectives.
The Payload Module consists of a 1.2 m three-mirror Korsch type telescope and of two instruments, the visible imager
and the near-infrared spectro-photometer, both covering a large common field-of-view enabling to survey more than
35% of the entire sky. All sensor data are downlinked using K-band transmission and processed by a dedicated ground
segment for science data processing. The Euclid data and catalogues will be made available to the public at the ESA
Science Data Centre.
The success of the Euclid's NISP (Near-Infrared Spectro-Photometer) instrument for the Euclid mission requires very high performance detectors for which tight specifications have been defined. These must be verified over more than 95% of the focal plane which is equipped with 16 H2RG infrared pixel detectors. Teledyne will provide these detectors and their electronics under ESA and NASA contracts. The detectors will be selected, qualified then delivered to the NISP instrument under Euclid specifications. To prepare the future calibration plan, these detectors must also be fully characterized at the pixel level before their integration. This characterization is crucial to the future processing and in-flight calibration. For a good control of the performance, the detector specifications for Euclid require in one hand to know some characteristics such as noise and dark current at a level as low as 10-3 e- /s , but also in other hand, require to have model of some specific properties of these detectors such as their non-linearity response, or their latency signals, which will imply specific measurements, characterization and studies. For this purpose, we have constructed dedicated facilities, and prepared a full test plan with adapted analysis methods and software tools that will be used to calibrate flight detectors. Here we describe the status of this plan, the facilities and their validation. We then present some preliminary results on dark current, total noise, CDS noise and some first estimations of persistence, using high performance engineering grade Euclid detectors provided by ESA. A pilot run is foreseen at the end of the year to validate the full test plan. Next step will be the characterization of flight detectors expected to start mid 2016.
The detector system (DS) of Euclid NISP’s instrument (Near-Infrared Spectro-Photometer) is a matrix of 16 H2RG infrared detectors acquired simultaneously. After their characterization done at CPPM (Centre de Physique des Particules de Marseille), these detectors are integrated into a mechanical structure designed at LAM (Laboratoire d'Astronomie de Marseille) and called NI-FPA (Focal Plane Array) Before delivering the full instrument to ESA several test models have to demonstrate the performances of the detector system. The first test model, the Demonstrator Model (DM), has been integrated and tested in dedicated facilities at LAM. The aim was to validate both the integration process and the simultaneous acquisition of the detectors. Dark, noise, self-compatibility and EMC performances are presented in this paper.
We present digital holographic interferometry (DHI) in the long-wave infrared for monitoring the deformation under cryogenic conditions of a segmented focal plane array to be used in a space mission. The long wavelength was chosen for its ability to allow measurement of displacements 20 times larger than DHI in the visible and which were foreseen with the test object under such temperature changes. The specimen consists of 4x4 mosaic of detectors assembled on a frame. It was required to assess the global deformation of the ensemble, the deformation of each detector, and piston movements of each of them with respect to their neighbors. For that reason we incorporated the temporal phase unwrapping by capturing a sufficiently high number of holograms between which the phase does not suffer strong variations. At last since the specimen exhibit specular reflectivity at that wavelength, it is illuminated through a reflective diffuser.
In June 2012, Euclid, ESA's Cosmology mission was approved for implementation. Afterwards the industrial contracts were signed for the payload module and the spacecraft prime, and the mission requirements consolidated. We present the status of the mission in the light of the design solutions adopted by the contractors. The performances of the spacecraft in its operation, the telescope assembly, the scientific instruments as well as the data-processing have been carefully budgeted to meet the demanding scientific requirements. We give an overview of the system and where necessary the key items for the interfaces between the subsystems.
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.
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.
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.
Euclid is a space-borne survey mission developed and operated by ESA. It is designed to understand the origin of the
Universe's accelerating expansion. Euclid will use cosmological probes to investigate the nature of dark energy, dark
matter and gravity by tracking their observational signatures on the geometry of the Universe and on the history of
structure formation. The mission is optimised for the measurement of two independent cosmological probes: weak
gravitational lensing and galaxy clustering. The payload consists of a 1.2 m Korsch telescope designed to provide a large
field of view. The light is directed to two instruments provided by the Euclid Consortium: a visual imager (VIS) and a
near-infrared spectrometer-photometer (NISP). Both instruments cover a large common field of view of 0.54 deg2, to be
able to survey at least 15,000 deg2 for a nominal mission of 6 years. An overview of the mission will be presented: the
scientific objectives, payload, satellite, and science operations. We report on the status of the Euclid mission with a
foreseen launch in 2019.
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.
This paper presents the GWA and the Compensating mechanism of the Near Infrared SpectroPhotometer (NISP) instrument of the ESA Euclid mission. The NIS instrument should perform an exposure sequence in the wave length range [0.9 - 2.0Jum with different exposures of the same field of views with different passband grisms with two orthogonal dispersion directions and two wavelength range. These functionalities will be achieved by a mechanism supporting the optical elements: the Grism Wheel Assembly (GWA). The required positioning repeatability is in the order of few arcsec to keep the spectra aligned with the detector pixel columns/rows. The GWA will be assembled to the NISP Optomechanical Assembly (NIOMA) with an operating temperature of 140K. A further mechanism is necessary to compensate the torque perturbances induced by the two large wheels. It is based onto a stepper motor that will drive a flywheel.
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.
replace the current satellite system in the 2020 timeframe and contribute to the Joint Polar System to be set up with
NOAA. Through consultation with users and application experts, requirements have been defined for a range of
candidate missions mainly in support of operational meteorology and climate monitoring. A number of on-board
instruments, satellite platforms and ground support infrastructure are under study in coordination with ESA, NOAA,
DLR and CNES. The satellites will fly in a sun synchronous, low earth orbit at 817 km altitude and 09:30 descending
equatorial crossing time, providing observations with global coverage every 12 to 24 hours depending on instrument.
The instruments exploit a range of techniques including multi spectral imaging, atmospheric sounding in the optical and
microwave spectral domains, radio occultation sounding, scatterometry and microwave imaging. The raw instrument
data will be broadcast directly by the satellites, as well as being stored on board for their transmission, in sets spanning
up to a full orbit, to polar ground stations. These data will be collected at EUMETSAT facilities and processed to obtain
calibrated and geo-located measurements, and records of well defined geophysical variables. The data will be distributed
to the users in near real time and archived together with the data of other EUMETSAT satellite systems, making
available long term records also suitable for climate monitoring. Feasibility studies for the space and ground systems will
be done until early 2012 with the main objective to select the baseline configuration for preliminary definition,
development and operation programmes to be proposed and coordinated within the involved organisations.
The Infrared Atmospheric Sounding Interferometer (IASI) is a key payload element of the METOP series of European meteorological polar-orbit satellites. IASI will provide very accurate data about the atmosphere, land and oceans for application to weather predictions and climate studies. The IASI measurement technique is based on passive IR remote sensing using an accurately calibrated Fourier Transform Spectrometer operating in the 3.7 - 15.5 μm spectral range and an associated infrared imager operating in the 10.3-12.5 μm spectral range. The optical configuration of the sounder is based on a Michelson interferometer. Interferograms are processed by the on-board digital processing subsystem which performs the inverse Fourier Transform and the radiometric calibration. The integrated infrared imager allows the co registration of the IASI sounder with AVHRR imager on-board METOP.
The first model (proto-flight) of IASI has successfully completed a verification program conducted at ALCATEL SPACE premises in Cannes. This paper provides a brief overview of the IASI mission, instrument architecture and key performances results. A companion paper1 by Alcatel provides more information on instrument design and development.
KEYWORDS: Interferometers, Calibration, Sensors, Mirrors, Black bodies, Digital signal processing, Temperature metrology, Thermal modeling, Interfaces, Electronics
The purpose of this paper is to present the IASI overall architecture and the IASI functional chain including optics and interferometer, analogue to digital acquisition, on board and on ground digital processing. It points out special features of IASI's design and critical technologies. The IASI technical description is followed by a development status including activities on breadboards, engineering models, proto flight and flight models with emphasis put on achieved critical steps. A companion paper by CNES will provide detailed information on the IASI mission and instrument key performance achievement.
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