Monitoring water quality in large dams is becoming a necessity for protecting stored water from various forms of pollution. This process requires analysis of several samples on a weekly or monthly basis. Our study aims to determine the relationship between water quality parameters (WQP) and digital data from the Sentinel-2 satellite to estimate and map the WQP in the Bin El Ouidane Reservoir. The in situ sampling was carried out in the Bin El Ouidane Reservoir (Azilal Province), followed by analysis of physicochemical parameters in the laboratory. These measurement results were compared with the reflectance in each sampling location to investigate the correlations between bands and laboratory chemical analysis results. The correlation results showed that all studied parameters have an R greater than 0.52, and they can be transformed to predictive models by stepwise regression. The accuracy of our proposed models was tested using the Oum Er-Rbia Hydraulic Basin Agency data, and the results showed that only three parameters yield admissible verification results (Chlorophyll A, dissolved Oxygen and Nitrate). Those models were then used in geographic information system software to produce a thematic map of each parameter over the entire surface of the reservoir. As a conclusion, the Sentinel-2 images could help indicate the eutrophication stage in the Bin El Ouidane Reservoir, which is a major risk in major Moroccan reservoirs.

/pdf/evaluating-the-potential-of-sentinel-2-satellite-images-for-4ysj4ne6me.pdf

Evaluating the potential of Sentinel-2 satellite images for water quality characterization of artificial reservoirs: The Bin El Ouidane Reservoir case study (Morocco)

ARIEL (the Atmospheric Remote-sensing Infrared Exoplanet Large-survey) is one of the three candidates for the next
ESA medium-class science mission (M4) expected to be launched in 2026. This mission will be devoted to observing
spectroscopically in the infrared a large population of warm and hot transiting exoplanets (temperatures from ~500 K to
~3000 K) in our nearby Galactic neighborhood, opening a new discovery space in the field of extrasolar planets and
enabling the understanding of the physics and chemistry of these far away worlds. The three candidate missions for M4
are now in a Phase A study which will run until mid-2017 at which point one mission will be selected for
implementation.
ARIEL is based on a 1-m class telescope feeding both a moderate resolution spectrometer covering the wavelengths
from 1.95 to 7.8 microns, and a four channel photometer (which also acts as a Fine Guidance Sensor) with bands
between 0.55 and 1.65 microns. During its 3.5 years of operation from an L2 orbit, ARIEL will continuously observe
exoplanets transiting their host star.

An integrated payload design for the Atmospheric Remote-sensing Infrared Exoplanet Large-survey (ARIEL)

Infrared image sensor developments supported by the European Space Agency

In this paper, the flexibility of long-wavelength Type-II InAs/GaSb superlattice (Ga-containing SL) is explored and investigated from the growth to the device performance. First, several samples with different SL period composition and thickness are grown by molecular beam epitaxy. Nearly strain-compensated SLs on GaSb exhibiting an energy band gap between 105 to 169 meV at 77K are obtained. Second, from electronic band structure calculation, material parameters are extracted and compared for the different grown SLs. Finally, two p-i-n device structures with different SL periods are grown and their electrical performance compared. Our investigation shows that an alternative SL design could potentially be used to improve the device performance of diffusion-limited devices for long-wavelength infrared detection.

/pdf/flexibility-of-ga-containing-type-ii-superlattice-for-long-6qsr06ie3o.pdf

Flexibility of Ga-containing Type-II superlattice for long-wavelength infrared detection

The Payload Technology Validation section in the Future Missions office of ESA's Science directorate at ESTEC provides testing support to present and future missions at different stages in their lifetime, from early technology developments to mission operation validation. In this framework, a test setup to characterize near-infrared (NIR) detectors has been created. In the context of the Astronomy Large Format Array for the near-infrared ("ALFA-N") technology development program, detectors from different suppliers are tested. We report on the characterization progress of the ALFA-N detectors, for which a series of rigorous tests have been performed on two different detectors; one provided by CEA/Leti-CEA/IRFU-SOFRADIR, France and the other by SELEX- UK/ATC, UK. Experimental techniques, the test bench and methods are presented. The conversion gain of two different detectors is measured using the photon transfer curve method. For a Leti LPE detector the persistence effect has been probed across a range of illumination levels to reveal a sharp linear increase of persistence below full-well and a plateauing beyond saturation. The same detector has been proton irradiated which has resulted in no significant dark current increase.

Large format array NIR detectors for future ESA astronomy missions: characterization and comparison

We report on the present and future detector development activities for the European Space Agency Science Programme. The development of European technology in that field is a key mission enabler for the program, which requires TRL6 (ISO scale) by end of the definition phase, so called "mission adoption". This is particularly true for Astronomy and fundamental physics type missions. Current activities are in particular targeting large format and p-channel CCD, NIR and MWIR, LWIR wavelength ranges as well as related ASIC controller. For the longer term future mission plan (so called M4, M5 and L2 missions, M3 being PLATO and L1 JUICE), the extreme ends of the spectrum will be addressed. An overview of the detector status for the Earth Observation program is given in appendix, as most of the technologies are directly applicable to some extent to science missions, in particular for Planetary missions. The specific validation activities in place in the future mission preparation office in support to the space science program will be eventually briefly detailed.

European Space Agency detector development for space science: present and future activities

The European Space Agency has a very strong interest in the performance enhancement of detector arrays for future scientific and astronomy missions. Improvements in Visible and Infrared wavelengths are of particular interest and the Agency undertakes a programme of continuous development aimed at enhancing the capability of detectors in these wavebands. This paper presents the status of these detector technology development activities.

The status of European Space Agency supported detector developments

For future near infrared astronomy missions, ESA is developing a complete detection and conversion chain (photon to SpaceWire chain system): 
Large Format Array (aLFA-N) based on MCT type detectors. 
aLFA-C (Astronomy Large Format Array Controller): a versatile cryogenic detector controller. An aLFA-C prototype was developed by Caeleste (Belgium) under ESA contract (400106260400). To validate independently the performances of the aLFA-C prototype and consolidate the definition of the follow-on activity, a dedicated test bench has been designed and developed in ESTEC/ESA within the Payload Technology Validation group. This paper presents the test setup and the performance validation of the first prototype of this controller at room and cryogenic temperature. Test setup and software needed to test the HAWAII-2RG and aLFA-N detectors with the aLFA-C prototype at cryogenic temperature will be also presented.

Large format array controller (aLFA-C): tests and characterisation at ESA

Detectors play a crucial role for the instrument design and the achievable instrument performance. The wavebands of interest for remote sensing are the visible and the infrared. Therefore, the European Space Agency has a strong interest in the performance enhancement of detector arrays in those spectral ranges. The Agency follows a continuous development strategy to enhance the capabilities for future Earth observation and astronomy missions. This paper presents the technical and planning status of these detector technology development activities.

https://www.spiedigitallibrary.org/conference-proceedings-of-spie/11180/111803R/Detector-development-activities-supported-by-the-European-Space-Agency/10.1117/12.2536054.pdf

Nick Nelms

Papers

European Space Agency detector development for space science: present and future activities

The status of European Space Agency supported detector developments

Large format array controller (aLFA-C): tests and characterisation at ESA

Detector development activities supported by the European Space Agency