KEYWORDS: Equipment, Calibration, Short wave infrared radiation, Design and modelling, Signal to noise ratio, Modulation transfer functions, Thermography, Tunable filters, Optical filters, Telescopes
The Land Surface Temperature Monitoring (LSTM), part of the expansion missions of the Copernicus programme, aims at providing data for land surface temperature and evapotranspiration at unprecedented spatio-temporal resolution, with the main objective of providing valuable data for improved water management at individual European field scale. This paper gives an overview of the instrument main requirements flowing down from the mission objectives, and the instrument design selected to fulfill them. The technical challenges are described as well as the key performances.
KEYWORDS: Equipment, Signal to noise ratio, Calibration, Short wave infrared radiation, Modulation transfer functions, Design and modelling, Astronomical imaging, Thermography, Tunable filters, Telescopes
The Land Surface Temperature Monitoring (LSTM), part of the expansion missions of the Copernicus programme, aims at providing data for land surface temperature and evapotranspiration at unprecedented spatio-temporal resolution, with the main objective of providing valuable data for improved water management at individual European field scale. This paper gives an overview of the instrument main requirements flowing down from the mission objectives, and the instrument design selected to fulfill them. The technical challenges are described as well as the preliminary predicted performances.
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Silicon nitride is a ceramic material that has very interesting stability properties for space telescopes. Indeed, the objective for telescopes is chiefly stability and with its high strength and stiffness and low CTE, Silicon Nitride is well suited for complex space structures. Thales Alenia Space has demonstrated the ability of Si3N4 to address those needs and requirements for complex designs such as tubes, brackets, brazed supports and bars. All these structures have been tested, qualified and flight proven. In addition, deep characterization of the material strength has been performed. Now that this material has been demonstrated as suitable for telescope structures, several R&D activities are pursued, from production via additive manufacturing to suitability for optical parts. This paper shows an overview of past, on-going and foreseen developments for the Silicon Nitride technology.
Silicon nitride is a ceramic material that has very interesting properties for space applications, especially for optical
instruments and telescopes. Indeed, the objective for such structures is chiefly stability to ensure performance, associated
with low mass and high stiffness to sustain launch loads. With its high strength and stiffness and low CTE, Silicon
Nitride is therefore extremely well suited for stable Space structures.
Thales Alenia Space has been using Silicon Nitride for more than a decade, and in that framework has evaluated the
ability of the material to address those needs and requirements for complex designs such as tubes, brackets, brazed
supports, beams and light-weighted plates. All these structures have been tested, qualified and are now flight proven.
In order to improve knowledge and mastering of strength properties, a characterization campaign of the material is under
way in a GSTP funded by CNES and driven by ESA. This paper describes the design of this test campaign, the choices
for the sample types and dimensions, and prediction of the expected results. In addition to the mechanical strength
testing, X-ray tomography has been implemented in order to detect flaws beforehand and to investigate the ability to
predict failure from the extracted information. This will be especially useful since verification (in particular proof tests
that are commonly used on ceramics for Space applications) is based on the relationship between strength and flaws. It is
expected that by improving this knowledge a more straightforward verification process can be derived.
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