The European Space Agency (ESA), in collaboration with the European Commission (EC) and EUMETSAT, is developing as part of the EC’s Copernicus programme, a space-borne observing system for quantification of anthropogenic carbon dioxide (CO2) emissions. The anthropogenic CO2 monitoring (CO2M) mission will be implemented as a constellation of identical Low Earth Orbit satellites, to be operated over a nominal period of more than 7 years. Each satellite will continuously measure CO2 concentration in terms of column-averaged dry air mole fraction (denoted XCO2) along the satellite track on the sun-illuminated part of the orbit, with a swath width of 250 km. Observations will be provided at a spatial resolution < 2 x 2 km2, with high precision (< 0.7 ppm) and accuracy (bias < 0.5 ppm), which are required to resolve the small atmospheric gradients in XCO2 originating from anthropogenic activities. The demanding requirements necessitate a payload composed of three instruments, which simultaneously perform co-located measurements: a push-broom imaging spectrometer in the Near Infrared (NIR) and Short-Wave Infrared (SWIR) for retrieving XCO2 and in the Visible spectral range (VIS) for nitrogen dioxide (NO2), a Multi Angle Polarimeter (MAP) and a three-band Cloud Imager (CLIM). Following the kick-off Mid 2020, the industrial activities have now passed the Satellite PDR allowing to enter in phase C/D. The paper will provide an overview of the space segment development achieved during the phase B2, including the platform, the payload activities as well as the end-to-end simulator. The preliminary design of the instruments on board the CO2M mission, the progress of the critical technological activities and the first results of the development models will be highlighted.
Thales Alenia Space has been selected to design and provide the payloads of the European Copernicus CO2M mission, whose main aim is to provide monitoring of the anthropogenic carbon dioxide emissions from space. Each payload is composed of : • The CO2 instrument, which is the instrument dedicated to measuring atmospheric CO2 and CH4. This dispersive instrument measures the spectral radiance in three bands (747-773, 1590-1675 and 1990-2095nm), used as inputs to the inverse models for determining total column concentrations for atmospheric CO2 and CH4. The instrument is designed for high spatial resolution, high spectral resolution, and high thermal and mechanical stabilities. • The CO2 instrument embeds an imaging spectrometer in the VIS 405-490nm band dedicated to measuring atmospheric NO2 content, permitting native nominal co-registration and optimized relative radiometric performances with the CO2 bands. This translates into an accurate tracing of anthropogenic CO2 plumes from power plants and cities while limiting the additional hardware and qualification procedures • This combined CO2 and NO2 instrument is the core of the payload, and two additional instruments of limited mass and volumes are embarked: a multi-angle polarimeter dedicated to aerosols measurement (MAP) to better account for cloud and aerosols scattering effects, and a cloud imager (CLIM) with high spatial resolution to accurately filter the data for cloud-contaminated samples. This article presents the payload design and development status.
The European Space Agency (ESA), in collaboration with the European Commission (EC) and EUMETSAT, is developing as part of the EC’s Copernicus programme, a space-borne observing system for quantification of anthropogenic carbon dioxide (CO2) emissions. The anthropogenic CO2 monitoring (CO2M) mission will be implemented as a constellation of identical Low Earth Orbit satellites, to be operated over a period of more than 7 years. Each satellite will continuously measure CO2 concentration in terms of column-averaged dry air mole fraction (denoted XCO2) along the satellite track on the sun-illuminated part of the orbit, with a swath width of 250 km. Observations will be provided at a spatial resolution < 4 km2 , with high precision (< 0.7 ppm) and accuracy (bias < 0.5 ppm), which are required to resolve the small atmospheric gradients in XCO2 originating from anthropogenic activities. The demanding requirements necessitate a payload composed of three instruments, which simultaneously perform co-located measurements: a push-broom imaging spectrometer in the Near Infrared (NIR) and Short-Wave Infrared (SWIR) for retrieving XCO2 and in the Visible spectral range (VIS) for nitrogen dioxide (NO2), a Multi Angle Polarimeter (MAP) and a three-band Cloud Imager (CLIM). Following the kick-off Mid 2020, the industrial activities have now passed the Satellite PDR allowing to enter the phase C/D. The paper summarises the payload activities performed during the phase B2 culminating with the PDR of the instruments and of the payload. The preliminary design of the CO2M mission’s instruments, the progress of the technological activities and the first results of the development models are presented.
The European Space Agency (ESA), in collaboration with the European Commission (EC) and
EUMETSAT, is developing as part of the EC’s Copernicus programme, a space-borne observing system for quantification of anthropogenic carbon dioxide (CO2) emissions. The anthropogenic CO2 monitoring (CO2M) mission will be implemented as a constellation of identical LEO satellites, to be operated over a period > 7 years and measuring CO2 concentration in terms of column-averaged dry air mole fraction (denoted as XCO2). Industrial activities for the phase B2CD have been kicked-off Mid 2020.
The demanding requirements necessitate a payload composed of a suite of instruments,
which simultaneously perform co-located measurements. A push-broom imaging spectrometer will perform co-located measurements of top-of-atmosphere radiances in the Near Infrared (NIR) and Short-Wave Infrared (SWIR) at high to moderate spectral resolution (NIR: 747- 773nm @0.1nm, SWIR-1: 1595-1675nm @0.3nm, SWIR-2: 1990-2095nm @0.35nm) for retrieving XCO2. These observations are complemented in the same spectrometer by measurements in the visible spectral range (405-490 nm @0.6nm), providing vertical column measurements of nitrogen dioxide (NO2) that serve as a tracer to high temperature combustion of fossil-fuel and related emission plumes (e.g. from coal-fired power plants and cities). High quality retrievals of XCO2 will be ensured even in situations of large aerosol loading, thanks to co-located measurements of aerosol resulting from a Multiple- Angle Polarimeter (MAP). Polarimetric measurements are performed over 40 angular views and in six spectral channels between 410 and 865 nm. Finally, due to the strong sensitivity of the XCO2 retrieval to cloud contamination, a three-band Cloud Imager (CLIM) will provide the required capacity to detect small tropospheric clouds and cirrus cover with an accuracy of 1% to 5% and a sampling better than 400 m.
The European Space Agency (ESA), in collaboration with the European Commission (EC) and EUMETSAT, is developing a space-borne observing system for quantification of anthropogenic carbon dioxide (CO2) emissions. Forming part of the EC's Copernicus programme, the CO2 monitoring (CO2M) mission will be implemented as a constellation of identical satellites, to be operated over a period > 7 years and measuring CO2 concentration in terms of column-averaged mole fraction (denoted as XCO2). Each satellite will continuously image XCO2 along the satellite track on the sun-illuminated part of the orbit, with a swath width of >250 km. Observations will be provided at a spatial resolution < 2 x 2 km2 near the swath center, with high precision (<0.7 ppm) and accuracy (bias <0.5 ppm). To this end, the payload comprises a suite of instruments addressing the various aspects of the challenging observation requirements: A push-broom imaging spectrometer will perform co-located measurements of top-of-atmosphere radiances in the Near Infrared (NIR) and Short-Wave Infrared (SWIR) at high to moderate spectral resolution (NIR: 747-773nm@0.1nm, SWIR-1: 1595-1675nm@0.3nm, SWIR-2: 1990-2095nm@0.35nm). These observations are complemented by measurements in the visible spectral range (405-490 nm@0.6nm), providing vertical column measurements of nitrogen dioxide (NO2) that serve as a tracer to assist the detection of fossil-fuel emission plumes (e.g. from coal-fired power plants and cities). High quality retrievals of XCO2 will be ensured even over polluted industrial regions, thanks to co-located measurements of aerosols performed by a Multiple-Angle Polarimeter (MAP). Finally, measurements of a three-band Cloud Imager, co-registered with the CO2 observations, will provide the required cloud-flagging capacity at sub-sample level (<200m resolution).
The presentation will review the results of the Phase A/B1 instrument studies carried out in 2018-2019, including technology pre-development activities, and highlight the identified engineering challenges. The preliminary design of the CO2M mission’s instruments at the beginning of the implementation phase will be presented, along with an outlook on the development activities under the Phase B2CD programme.
MUSE (Multi Unit Spectroscopic Explorer) is a second generation instrument developed for ESO (European Southern
Observatory) to be installed on the VLT (Very Large Telescope) in year 2012. The MUSE project is supported by a
European consortium of 7 institutes. After a successful Final Design Review the project is now facing a turning point
which consist in shifting from design to manufacturing, from calculation to test, ... from dream to reality.
At the start, many technical and management challenges were there as well as unknowns. They could all be derived of
the same simple question: How to deal with complexity? The complexity of the instrument, of the work to de done, of
the organization, of the interfaces, of financial and procurement rules, etc.
This particular moment in the project life cycle is the opportunity to look back and evaluate the management methods
implemented during the design phase regarding this original question. What are the lessons learn? What has been
successful? What could have been done differently? Finally, we will look forward and review the main challenges of the
MAIT (Manufacturing Assembly Integration and Test) phase which has just started as well as the associated new
processes and evolutions needed.
We propose a new concept of diffractive optics: Fresnel arrays, for a 4 m aperture space telescope in the UV
domain.
Fresnel arrays focus light by diffraction through a very thin binary mask. They form images optically and
deliver very high quality wavefronts, specially in the UV. Up to 8% of the incident light is focussed, providing
high angular resolution and high contrast images of compact objects.
Due to their focal lengths of a few kilometers in the UV, large Fresnel arrays will require two spacecraft
in formation flying, but with relatively tolerant positioning. Diffraction focusing is also very chromatic; this
chromatism is corrected, allowing relatively broad (30 to 100 nm) spectral channels in the 120-350 nm range.
A 4 m aperture Fresnel imager providing 7 to 10 milli arc seconds resolution is very competitive for imaging
compact and high contrast objects such as protoplanetary disks and young planetary systems, AGNs, and deep
sky objects.
We have developed prototypes to validate the optical concept and related technologies : first a laboratory
setup, then a 20 cm aperture ground-based prototype, which provides high contrast and diffraction limited images
of sky objects in the visible and close IR. A new laboratory prototype is also being prepared for validation in
the 250 - 350 nm wavelength range.
MUSE is the Multi Unit Spectroscopic Explorer, an AO-assisted integral field spectrograph for visible and
near-IR wavelengths which is planned to be commissioned at the UT4 of the Very Large Telescope in 2012.1 We
present the status on the modeling of the spatial PSF at the UT focus and its Field-of-View (FoV) and spectral
variations. Modeling these variations and studying their implications is a cornerstone for some MUSE data
analysis and processing problems such as fusion, source extraction and deconvolution of MUSE datacubes.
In Wide Field Mode (WFM, 1 square arc-minute FoV, 0.2 arcsec spatial sampling), MUSE can operate
without Adaptive Optics (AO) correction or with a Ground Layer Adaptive Optics facility aimed at providing
an almost uniform correction over a large field of view. In Narrow Field Mode (7.5 square arcseconds FoV, 0.025
arcsec spatial sampling) MUSE will make use of a Laser Tomography Adaptive Optics reconstruction, implying
stronger spatial variations. By using the adaptive optics simulation tool PAOLA, we simulate in WFM the
spatial PSF as a function of atmospheric turbulence parameters, observed wavelengths, AO mode and position
in the field of view. We then develop a mathematical model fitting the generated data which allows, with a small
number of parameters, to approximate the PSF at any spatial and spectral position of MUSE datacube. Finally,
we evaluate the possibility to estimate the model parameters directly from the (future) MUSE data themselves.
Summary: The Multi Unit Spectroscopic Explorer (MUSE) is a second-generation VLT panoramic integral-field
spectrograph currently in manufacturing, assembly and integration phase. MUSE has a field of 1x1 arcmin2 sampled at
0.2x0.2 arcsec2 and is assisted by the VLT ground layer adaptive optics ESO facility using four laser guide stars. The
instrument is a large assembly of 24 identical high performance integral field units, each one composed of an advanced
image slicer, a spectrograph and a 4kx4k detector. In this paper we review the progress of the manufacturing and report
the performance achieved with the first integral field unit.
The concept of a gamma-ray telescope based on a Laue lens offers the possibility to increase the sensitivity by more
than an order of magnitude with respect to existing instruments. Laue lenses have been developed by our
collaboration for several years : the main achievement of this R&D program was the CLAIRE lens prototype, which
has successfully demonstrated the feasibility of the concept in astrophysical conditions. Since then, the endeavour
has been oriented towards the development of efficient diffracting elements (crystal slabs) in order to increase both
the effective area and the width of the energy bandpass focused, the aim being to step from a technological Laue lens
to a scientifically exploitable lens. The latest mission concept featuring a gamma-ray lens is the European Gamma-
Ray Imager (GRI) which intends to make use of the Laue lens to cover energies from 200 keV to 1300 keV.
Investigations of two promising materials, low mosaicity copper and gradient concentration silicongermanium
are presented in this paper. The measurements have been performed during three runs: 6 + 4 days at the
European Synchrotron Radiation Facility (Grenoble, France), on beamline ID15A, using a 500 keV monochromatic
beam, and 14 days on the GAMS 4 instrument of the Institute Laue Langevin (Grenoble, France) featuring a highly
monochromatic beam of 517 keV. Despite it was not perfectly homogeneous, the presented copper crystal has
exhibited peak reflectivity of 25 % in accordance with theoretical predictions, and a mosaicity around 26 arcsec, the
ideal range for the realization of a Laue lens such as GRI. Silicon-germanium featuring a constant gradient have
been measured for the very first time at 500 keV. Two samples showed a quite homogeneous reflectivity reaching
26%, which is far from the 48 % already observed in experimental crystals but a very encouraging beginning. The
measured results have been used to estimate the performance of the GRI Laue lens design.
This paper presents the results of a Fresnel Interferometric Array testbed. This new concept of imager involves
diffraction focussing by a thin foil, in which many thousands of punched subapertures form a pattern related
to a Fresnel zone plate. This kind of array is intended for use in space, as a way to realizing lightweight large
apertures for high angular resolution and high dynamic range observations. The chromaticity due to diffraction
focussing is corrected by a small diffractive achromatizer placed close to the focal plane of the array.
The laboratory test results presented here are obtained with an 8 centimeter side orthogonal array, yielding
a 23 meter focal length at 600 nm wavelength. The primary array and the focal optics have been designed and
assembled in our lab. This system forms an achromatic image. Test targets of various shapes, sizes, dynamic
ranges and intensities have been imaged. We present the first images, the achieved dynamic range, and the
angular resolution.
This paper presents progress made regarding the field to resolution ratio for aperture synthesis interferometers. In order to overcome a limit established for the field to resolution ratio of interferometric arrays, we propose an interferometer configuration which allows a better coverage of the spatial frequency plane. This setup requires large sub-apertures, which can be built more easily with a diffractive Fresnel plates than with large mirrors. We compare a dense array of 9 Fresnel sub-apertures, which gives a snapshot field-resolution ratio of 400, versus a sparse array of 150 small apertures, which yields a field-resolution ratio of 150.
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.