As part of its contribution to Earth observation from space, ALCATEL SPACE designed, built and tested the High Resolution cameras for the European intelligence satellites HELIOS I and II. Through these programmes, ALCATEL SPACE enjoys an international reputation. Its capability and experience in High Resolution instrumentation is recognised by the most customers.Coming after the SPOT program, it was decided to go ahead with the PLEIADES HR program. PLEIADES HR is the optical high resolution component of a larger optical and radar multi-sensors system : ORFEO, which is developed in cooperation between France and Italy for dual Civilian and Defense use. ALCATEL SPACE has been entrusted by CNES with the development of the high resolution camera of the Earth observation satellites PLEIADES HR.The first optical satellite of the PLEIADES HR constellation will be launched in mid-2008, the second will follow in 2009. To minimize the development costs, a mini satellite approach has been selected, leading to a compact concept for the camera design.The paper describes the design and performance budgets of this novel high resolution and large field of view optical instrument with emphasis on the technological features.This new generation of camera represents a breakthrough in comparison with the previous SPOT cameras owing to a significant step in on-ground resolution, which approaches the capabilities of aerial photography.Recent advances in detector technology, optical fabrication and electronics make it possible for the PLEIADES HR camera to achieve their image quality performance goals while staying within weight and size restrictions normally considered suitable only for much lower performance systems.This camera design delivers superior performance using an innovative low power, low mass, scalable architecture, which provides a versatile approach for a variety of imaging requirements and allows for a wide number of possibilities of accommodation with a minisatellite class platform.

Coming after the SPOT satellites series, PLEIADES-HR is a CNES optical high resolution satellite dedicated to Earth observation, part of a larger optical and radar multi-sensors system, ORFEO, which is developed in cooperation between France and Italy for dual Civilian and Defense use. The development of the two PLEIADES-HR cameras was entrusted by CNES to Thales Alenia Space. This new generation of instrument represents a breakthrough in comparison with the previous SPOT instruments owing to a significant step in on-ground resolution, which approaches the capabilities of aerial photography. The PLEIADES-HR instrument program benefits from Thales Alenia Space long and successful heritage in Earth observation from space. The proposed solution benefits from an extensive use of existing products, Cannes Space Optics Centre facilities, unique in Europe, dedicated to High Resolution instruments. The optical camera provides wide field panchromatic images supplemented by 4 multispectral channels with narrow spectral bands. The optical concept is based on a four mirrors Korsch telescope. Crucial improvements in detector technology, optical fabrication and electronics make it possible for the PLEIADES-HR instrument to achieve the image quality requirements while respecting the drastic limitations of mass and volume imposed by the satellite agility needs and small launchers compatibility. The two flight telescopes were integrated, aligned and tested. After the integration phase, the alignment, mainly based on interferometric measurements in vacuum chamber, was successfully achieved within high accuracy requirements. The wave front measurements show outstanding performances, confirmed, after the integration of the PFM Detection Unit, by MTF measurements on the Proto-Flight Model Instrument. Delivery of the proto flight model occurred mi-2008. The FM2 Instrument delivery is planned Q2-2009. The first optical satellite launch of the PLEIADES-HR constellation is foreseen beginning-2010, the second will follow beginning-2011.

2020 has been a key year in the MeteoSat Third Generation (MTG), with the integration and tests of the Flexible Combined Imager (FCI) proto-flight model(PFM). The FCI is the imaging instrument of the MeteoSat Third Generation mission, whose first satellite MTG-I1 will be launched in the second half of 2022. Its large spectral coverage, its fast and flexible scanning, associated with demanding radiometric and optical performances will allow a step forward in Europe weather nowcasting.In 2018, three complementary development models were successfully integrated and tested. The Engineering Model validated the optical and radiometric performances of the detection chain. The Structural and Thermal Model qualified the robustness of the design against launch and in-orbit environments and validated the consistency with the thermal and microvibration mathematical model predictions. The Avionic Test Bench with the software which reached a very good level of maturity, validated the control, command and data handling of the instrument.The completion of these developments enabled to successfully hold the instrument Critical Design Review (CDR) end 2018.In 2019, the two main components of the instrument, namely the telescope assembly and the detection control electronics assembly (DCEA) successfully passed the acceptance tests and have been delivered.The article will present first an overview of the instrument design and the main outcomes of the development models. Then, it will discuss the up-to-date status of the FCI PFM development. Finally, it will introduce the overall planning for the four FCI models to be delivered to the MTG-I satellite series. This work has been performed under an ESA contract to Thales Alenia Space-France.

Meteosat Third Generation is the next ESA Program of Earth Observation dedicated to accurate prediction of meteorological phenomena and climate monitoring. The satellites will be operating from the Geostationary orbit using a 3-axes stabilized platform. The main instrument is called the Flexible Combined Imager (FCI), currently under development by Thales Alenia Space France, the PFM being integrated and tested in our Cannes facilities. This instrument will provide full images of the Earth every 10 minutes in 16 spectral channels between 0.44 and 13.3 µm, with a ground resolution ranging from 0.5 km to 2 km. The FCI is composed of a Korsch telescope developed by OHB, followed by an assembly of lenses and detectors called the Spectral Separation and Detection Assembly (SSDA) which is integrated by Thales Alenia Space. Both the telescope and SSDA have been separately tested as sub-systems before being integrated. This article will describe the principle and results of the optical tests performed on these sub-systems. In particular the telescope WFE, focal length and line of sight have been proved to be compliant to the respective success criteria. Concerning the SSDA, we will present the results of MTF measurements, co-registration between spectral channels and polarization, which were also all found compliant to their respective success criterion. Stray-light for both the telescope and SSDA has been characterized on-ground in order to provide the input necessary for the development of image correction algorithms. During the first half of 2020, these two successfully tested sub-systems were integrated together to build the FCI PFM, which will undergo optical vacuum testing at the timeframe of beginning 2021 before being delivered to the satellite.

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