Euclid is a European Space Agency mission dedicated to the mapping of the dark Universe launched the 1st of July 2023. The mission will investigate the distance-redshift relationship and the evolution of cosmic structures. This is achieved by measuring shapes and redshifts of galaxies and clusters of galaxies up to 10 billion years away. Euclid makes use of two cosmological probes, in a wide survey over the full extragalactic sky: the Weak Gravitational Lensing (WL) and the Baryonic Acoustic Oscillations (BAOs). The WL is a method to map the dark matter and measure dark energy by measuring the apparent distortion of galaxy images by mass inhomogeneities along the line-of-sight. This probe requires extreme image quality thus constraining the optical system imaging quality and its characterization both on-ground and in-flight. The BAOs are wiggle patterns, imprinted in the clustering of galaxies, which provide a standard ruler to measure dark energy and the expansion in the Universe. The first images were released on the 7th of November 2023 showcasing the capabilities of the space segment. To achieve the stunning first images and the scientific objectives of the mission, the space segment (i.e. the spacecraft) underwent a thorough and extensive test campaign on-ground. These tests demonstrated the excellent image quality and the overall stability of both the payload and the spacecraft in a representative operational environment. In complement, further tests were performed during the commissioning phase, just after launch, to validate the spacecraft pointing stability.
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 Euclid mission, the spacecraft being the essential space element, has been developed to undertake the challenges of investigate the dark energy and dark matter distribution in the Universe. As the launch date is approaching, the telescope and the integrated payload, encompassing the telescope and with the two science instruments attached behind it, have been successfully tested. The telescope alone was tested under ambient conditions, and the integrated payload was tested in vacuum at operational temperature. The extensive test campaign at telescope level confirmed that its optical performance were better than the required levels. The thermal-vacuum test campaign demonstrated the excellent stability of the optical performance of the entire payload module. In addition, other performances of the integrated payload were tested to gather information on the behavior of the payload which will be used for the preparation of the calibrations in-flight.
Euclid-VIS is the large format visible imager for the ESA Euclid space mission in their Cosmic Vision program, scheduled for launch in 2021. Together with the near infrared imaging within the NISP instrument, it forms the basis of the weak lensing measurements of Euclid. VIS will image in a single r+i+z band from 550-900 nm over a field of view of ~0.5 deg2 . By combining 4 exposures with a total of 2260 sec, VIS will reach to deeper than mAB=24.5 (10s) for sources with extent ~0.3 arcsec. The image sampling is 0.1 arcsec. VIS will provide deep imaging with a tightly controlled and stable point spread function (PSF) over a wide survey area of 15000 deg2 to measure the cosmic shear from nearly 1.5 billion galaxies to high levels of accuracy, from which the cosmological parameters will be measured. In addition, VIS will also provide a legacy dataset with an unprecedented combination of spatial resolution, depth and area covering most of the extra-Galactic sky. Here we will present the results of the study carried out by the Euclid Consortium during the period up to the beginning of the Flight Model programme
In the frame work of the ESA Euclid mission to be launched in 2020, the Euclid Consortium is developing an extremely large and stable focal plane for the VIS instrument. After an extensive phase of definition and study over 4 years made at CEA on the thermo-mechanical architecture of that Focal Plane, the first model (Structural and Thermal Model) has been assembled qualified and delivered to MSSL in June 2017.
The VIS Focal Plane Assembly integrates 36 CCDs (operated at 150K) connected to their front end electronics (operated at 280K). This Focal Plane will be the largest focal plane (~0.6 billion pixels) ever built for space application after the GAIA one. The CCDs are CCD273 type specially designed and provided by the Teledyne e2v company under ESA contract, front end electronics is studied and provided by MSSL.
The Structural and Thermal Model is fully representative of the Flight Model regarding the thermo-mechanical architecture. As the instrument development philosophy follows a Proto Flight approach this choice has been made very early in the development program in order to reduce the risk on the PFM program. So the AIT/AIV plan has been built in order to fully validate since the STM program the overall integration, verification and qualification sequences, taking into account the very stringent cleanliness requirement. The STM FPA integrates 36 CCDs representative of the flight model except for the detection function. Electrical configuration of the front end electronics provides electrical interface in order to power the CCDs and check integrity of all the electrical links to CCDs.
In this paper we first recall the architecture of the VIS-FPA and especially the solutions proposed to cope with the scientific needs of an extremely stable focal plane, both mechanically and thermally leading to a SiC structure. The modular architecture concept, considered as a key driver for such big and complex focal plane is detailed. Parallel to that, the integration workflow including verification steps is fully depicted including specific aspects linked to the use of SiC. Validation and qualification test program is described. A summary of geometrical measurements, thermal balance tests and vibrations tests including the main Ground Support Equipment description are reported.
Keyword list: Euclid, CCD, SiC, focal plane, architecture, integration
KEYWORDS: Electronics, Point spread functions, Charge-coupled devices, Power supplies, Calibration, Fermium, Frequency modulation, Sensors, Field programmable gate arrays, Clocks
Euclid is a medium class European Space Agency mission scheduled for launch in 2020. The goal of the survey is to examine the nature of Dark Matter and Dark Energy in the Universe. One of the cosmological probes used to analyze Euclid’s data, the weak lensing technique, measures the distortions of galaxy shapes and this requires very accurate knowledge of the system point spread function (PSF). Therefore, to ensure that the galaxy shape is not affected, the detector chain of the telescope’s VISible Instrument (VIS) needs to meet specific performance performance requirements. Each of the 12 VIS readout chains consisting of 3 CCDs, readout electronics (ROE) and a power supply unit (RPSU) will undergo a rigorous on-ground testing to ensure that these requirements are met. This paper reports on the current status of the warm and cold testing of the VIS Engineering Model readout chain. Additionally, an early insight to the commissioning of the Flight Model calibration facility and program is provided.
KEYWORDS: Point spread functions, Space operations, Galactic astronomy, Space telescopes, Charge-coupled devices, Calibration, Staring arrays, Sensors, Camera shutters, Radiation effects
Euclid-VIS is the large format visible imager for the ESA Euclid space mission in their Cosmic Vision program,
scheduled for launch in 2020. Together with the near infrared imaging within the NISP instrument, it forms the basis of
the weak lensing measurements of Euclid. VIS will image in a single r+i+z band from 550-900 nm over a field of view
of ~0.5 deg2. By combining 4 exposures with a total of 2260 sec, VIS will reach to deeper than mAB=24.5 (10σ) for
sources with extent ~0.3 arcsec. The image sampling is 0.1 arcsec. VIS will provide deep imaging with a tightly
controlled and stable point spread function (PSF) over a wide survey area of 15000 deg2 to measure the cosmic shear
from nearly 1.5 billion galaxies to high levels of accuracy, from which the cosmological parameters will be measured. In
addition, VIS will also provide a legacy dataset with an unprecedented combination of spatial resolution, depth and area
covering most of the extra-Galactic sky. Here we will present the results of the study carried out by the Euclid
Consortium during the period up to the Critical Design Review.
Euclid-VIS is the large format visible imager for the ESA Euclid space mission in their Cosmic Vision program,
scheduled for launch in 2020. Together with the near infrared imaging within the NISP instrument, it forms the basis of
the weak lensing measurements of Euclid. VIS will image in a single r+i+z band from 550-900 nm over a field of view
of ~0.5 deg2. By combining 4 exposures with a total of 2260 sec, VIS will reach to V=24.5 (10σ) for sources with extent
~0.3 arcsec. The image sampling is 0.1 arcsec. VIS will provide deep imaging with a tightly controlled and stable point
spread function (PSF) over a wide survey area of 15000 deg2 to measure the cosmic shear from nearly 1.5 billion
galaxies to high levels of accuracy, from which the cosmological parameters will be measured. In addition, VIS will also
provide a legacy dataset with an unprecedented combination of spatial resolution, depth and area covering most of the
extra-Galactic sky. Here we will present the results of the study carried out by the Euclid Consortium during the period
up to the Preliminary Design Review.
The focal plane array of the Euclid VIS instrument comprises 36 large area, back-illuminated, red-enhanced CCD detectors (designated CCD 273). These CCDs were specified by the Euclid VIS instrument team in close collaboration with ESA and e2v technologies. Prototypes were fabricated and tested through an ESA pre-development activity and the contract to qualify and manufacture flight CCDs is now underway. This paper describes the CCD requirements, the design (and design drivers) for the CCD and package, the current status of the CCD production programme and a summary of key performance measurements.
The edge illumination principle was first proposed at Elettra (Italy) in the late nineties, as an alternative method
for achieving high phase sensitivity with a very simple and flexible set-up, and has since been under continuous
development in the radiation physics group at UCL. Edge illumination allows overcoming most of the limitations
of other phase-contrast techniques, enabling their translation into a laboratory environment. It is relatively
insensitive to mechanical and thermal instabilities and it can be adapted to the divergent and polychromatic
beams provided by X-ray tubes. This method has been demonstrated to work efficiently with source sizes up
to 100m, compatible with state-of-the-art mammography sources. Two full prototypes have been built and
are operational at UCL. Recent activity focused on applications such as breast and cartilage imaging, homeland
security and detection of defects in composite materials. New methods such as phase retrieval, tomosynthesis
and computed tomography algorithms are currently being theoretically and experimentally investigated. These
results strongly indicate the technique as an extremely powerful and versatile tool for X-ray imaging in a wide
range of applications.
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