For Space Activities, more and more Corner Cubes, used as solution for retro reflection of light (telemetry and positioning), are emerging worldwide in different projects. Depending on the application, they can be massive or hollow Corner Cubes. For corners as well as for any kind of space optics, it usual that use of light/lightened components is always a baseline for purpose of mass reduction payloads. But other parameters, such as the system stability under severe environment, are also major issues, especially for the corner cube systems which require generally very tight angular accuracies.
For the particular case of the hollow corner cube, an alternative solution to the usual cementing of the 3 reflective surfaces, has been developed with success in collaboration with CNES to guarantee a better stability and fulfill the weight requirements.. Another important parameter is the dihedral angles that have a great influence on the wavefront error. Two technologies can be considered, either a Corner Cubes array assembled in a very stable housing, or the irreversible adherence technology used for assembling the three parts of a cube. This latter technology enables in particular not having to use cement. The poster will point out the conceptual design, the manufacturing and control key-aspects of such corner cube assemblies as well as the technologies used for their assembling.
The Infrared Atmospheric Sounding Interferometer New Generation (IASI-NG) is a key payload element of the second generation of European meteorological polar-orbit satellites (METOP-SG) dedicated to operational meteorology, oceanography, atmospheric chemistry, and climate monitoring. IASI-NG is designed with a very high level of accuracy being dedicated to operational meteorology, climate monitoring, characterization of atmospheric composition related to climate, atmospheric chemistry and environment. The performance objective is mainly a spectral resolution and a radiometric error divided by two compared with the IASI first generation ones.
The measurement technique is based on wide field passive Fourier Transform Spectrometer (operating in the 3.5 - 15.5 μm spectral range) based on an innovative Mertz compensated interferometer to manage the so-called self-apodization effect and the associated spectral resolution degradation.
We will present an overview of the instrument architecture and ongoing instrument development.
The Infrared Atmospheric Sounder Interferometer (IASI) is a Fourier Transform Spectrometer (FTS) working in the [3.6μm, 15.5μm] range, dedicated to Numerical Weather Prediction (NWP), atmospheric chemistry and climate monitoring. The second flight model (2 out of 3) is now in orbit and operational, as a payload of the MetOp-B satellite. A new generation of instrument (IASI-NG) to continue the IASI mission with increased performances is currently investigated by the French Space Agency (CNES). The performance objective is mainly a spectral resolution and a radiometric error divided by two compared with the IASI ones. Many different concepts of FTS were studied to try to fulfill these challenging requirements. This paper presents the different envisaged optical architecture and associated trade off. The major issue of the concept is to manage the so-called self-apodization of the interferogram and the associated degradation of the spectral resolution induced by the wider Field of View (FoV) and the longer Optical Path Difference (OPD). Increasing these two quantities have very constraining consequences on the optical architecture. Another critical point is the control of straylight which is quite severe and which has been taken into account early in the optical design. To assess the performances of the interferometer, different optical models were built combining analytical approach with ray tracing technics. We will describe the impacts of the demanding spectral requirements on the optical components and our analyses based on these models will be presented.