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The STereo Imaging Channel (STC) is one of the three channels of the SIMBIO-SYS instrument on board the BepiColombo ESA spacecraft. The design of the camera consists in a double wide-angle camera with two sub-channels looking at ±20° with respect to the nadir direction. Each sub-channel can acquire three quasi-contiguous areas of the Mercury surface in different colours determined by the filters mounted on the detector. The filters are divided in two categories: 4 broad band filters (20 nm of bandwidth and centred at 420, 550, 750 and 920 nm respectively) necessary to the chemical analysis of the Hermean surface; 2 panchromatic (PAN) filters with 200 nm of bandwidth and centred at 600 nm, designed for the stereo acquisition. The nominal Field of View (FoV) of each sub-channel is 5:38°x4:8°. The in-flight stellar calibration will be performed during the nominal mission using stellar fields images. To effectively plan this calibration activity, two analyses have been performed: the first one consists in simulating the observation of stars having different apparent magnitude to derive the best integration time needed to reach a specific Signal to Noise Ratio. Considering the characteristics of the STC camera and of its CMOS detector, the threshold magnitude needed for a star to be detectable will also be determined. The second part consists in selecting the stellar fields from the ESA GAIA archive and Tycho stellar catalogue that contain a pre-defined minimum number of stars required to perform the in-flight geometrical calibration. This selection have been performed taking into account stars brighter than the threshold defined in the first part.

The visible infrared thermal imaging spectrometer (VIRTIS) is one of the principal payloads to be launched in 2003 on ESA's Rosetta spacecraft. Its primary scientific objective s are to map the surface of the comet Wirtanen, monitor its temperature, and identify the solids and gaseous species on the nucleus and in the coma. VIRTIS will also collet data on two asteroids, one of which has been identified as Mimistrobell. The data is collected remotely using a mapping spectrometer co-boresighted with a high spectral resolution spectrometer. The mapper consists of a Shafer telescope matched to an Offner grating spectrometer capable of gathering high spatial, medium spectral resolution image cubes in the 0.25 to 5 micrometers waveband. The high spectral resolution spectrometer uses an echelle grating and a cross dispersing prism to achieve resolving powers of 1200 to 300 in the 1.9 to 5 micrometers band. Both sub-systems are passively cooled to 130 K and use two Sterling cycle coolers to enable two HgCdTe detector arrays to operate at 70 K. The mapper also uses a silicon back-side illuminated detector array to cover the ultra-violet to near-infrared optical band.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.