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Spectral and radiometric requirements of optical filters for space applications are always more demanding. Multispectral bandpass filters require very steep edges, a high accuracy in the central wavelength position, a high average transmittance as well as a very good level of blocking outside of the bandpass region.Realization of such filters implies to design the layer stacks in a way that reduces sensitivity to the production deviations and to be able to properly control the coating conditions in the machine.In order to optimize the design, a pre-production error analysis can be performed, to assess the weight of each layer in the global filter properties and therefore modify the design until a good stability level is achieved. We discuss different insitu optical monitoring strategies and process conditions depending on the coating technology. The realization phase needs a precise control of the coating machine such as well-characterized deposited materials, stable deposition rates, a reliable layer thickness monitoring system in addition to a good coating uniformity over all the coating positions inside the machine.We present design strategies and means of pre-production error analysis for typical multispectral bandpass specifications as well as transmittance curves.

Since the end of 1970s, EADS-SODERN has developed a series of detection units positioned in the focal plane of earth observation instruments and mounted on the French civil and military satellites like SPOT and HELIOS. Those detection units, designed for a push broom operating mode, have been progressively adapted to match the technical evolutions of the programmes.With PLEIADES High Resolution optical satellite CNES is proposing a completely new concept which has the capability to acquire the wide-swath of 20 km at nadir with panchromatic and multispectral imagery and a panchromatic mode resolution of 0.7 m at nadir. Within the industrial structure of this new programme, EADS SODERN is responsible for the development of the Focal Plane Assembly (FPA). This FPA, which is one of the most significant parts performing the imaging function, offers a wide variety of new technologies. This paper describes the design and performance budgets of this new FPA:o The mechanical support and thermal control with the Silicon Carbide (SiC) structure allows evacuating the detectors dissipation while maintaining stable the detection lines. o The folding mirrors are used to achieve the required limitation of panchromatic / multispectral distance with the constraint of detectors package size. o The spectral selection is made by strip filters place very close in front of the detectors.

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