The pre-launch characterization of SIMBIO-SYS/VIHI imaging spectrometer for the BepiColombo mission to Mercury. I. Linearity, radiometry, and geometry calibrations

Before integration aboard European Space Agency BepiColombo mission to Mercury, the visible and near infrared hyperspectral imager underwent an intensive calibration campaign. We report in Paper I about the radiometric and linearity responses of the instrument including the optical setups used to perform them. Paper II [F. Altieri et al., Rev. Sci. Instrum. 88, 094503 (2017)] will describe complementary spectral response calibration. The responsivity is used to calculate the expected instrumental signal-to-noise ratio for typical observation scenarios of the BepiColombo mission around Mercury. A description is provided of the internal calibration unit that will be used to verify the relative response during the instrument's lifetime. The instrumental spatial response functions as measured along and across the spectrometer's slit direction were determined by means of spatial scans performed with illuminated test slits placed at the focus of a collimator. The dedicated optical setup used for these measurements is described together with the methods used to derive the instrumental spatial responses at different positions within the 3 . 5 ° field of view and at different wavelengths in the 0.4-2.0 μm spectral range. Finally, instrument imaging capabilities and Modulated Transfer Function are tested by using a standard mask as a target

The spectral imaging facility: Setup characterization

The SPectral IMager (SPIM) facility is a laboratory visible infrared spectrometer developed to support space borne observations of rocky bodies of the solar system. Currently, this laboratory setup is used to support the DAWN mission, which is in its journey towards the asteroid 1-Ceres, and to support the 2018 Exo-Mars mission in the spectral investigation of the Martian subsurface. The main part of this setup is an imaging spectrometer that is a spare of the DAWN visible infrared spectrometer. The spectrometer has been assembled and calibrated at Selex ES and then installed in the facility developed at the INAF-IAPS laboratory in Rome. The goal of SPIM is to collect data to build spectral libraries for the interpretation of the space borne and in situ hyperspectral measurements of planetary materials. Given its very high spatial resolution combined with the imaging capability, this instrument can also help in the detailed study of minerals and rocks. In this paper, the instrument setup is first described, and then a series of test measurements, aimed to the characterization of the main subsystems, are reported. In particular, laboratory tests have been performed concerning (i) the radiation sources, (ii) the reference targets, and (iii) linearity of detector response; the instrumental imaging artifacts have also been investigated. <P /

The Ma_MISS/ExoMars 2020 spectrometer: on ground instrument calibration

The Ma_MISS FM spectrometer for ExoMars 2020 mission to Mars has been successfully calibrated, before integration in the FM Drill. Both spectral and radiometric calibration, together with validation measurements performed on rocks slabs, have demonstrated the capabilities of the instrument

SIMBIO-SYS Near Earth Commissioning Phase: a step forward toward Mercury

On December 2018, the Near Earth Commissioning Phase (NECP) has been place forSIMBIO-SYS (Spectrometers and Imagers for MPO BepiColombo Integrated Observatory - SYStem), the suite part of the scientific payload of the BepiColombo ESA-JAXA mission. SIMBIO-SYS is composed of three channels: the high resolution camera (HRIC), the stereo camera (STC) and the Vis/NIR spectrometer (VIHI) . During the NECP the three channels have been operated properly. For the three channels were checked the operativity and the performance. The commanded operations allowed to verify all the instrument functionalities demonstrating that all SIMBIO-SYS channels and subsystems work nominally. During this phase we also validated the Ground Segment Equipment (GSE) and the data analysis tools developed by the team

Preliminary LSF and MTF determination for the stereo camera of the BepiColombo mission

In the context of a stereo-camera, measuring the image quality allows to define the accuracy of the 3D reconstruction. In fact, depending on the precision of the camera position data, on the kind of reconstruction algorithm, and on the adopted camera model, it determines the vertical accuracy of the reconstructed terrain model. Aim of this work is to describe the results and the method implemented to determine the Line Spread Function (LSF) of the Stereoscopic Channel (STC) of the SIMBIOSYS imaging system for the BepiColombo mission. BepiColombo is the cornerstone mission n.5 of the European Space Agency dedicated to the exploration of the innermost planet of the Solar System, Mercury, and it is expected to be launched in 2016. STC is a double push-frame single-detector camera composed by two identical sub-channels looking at \ub121\ub0 wrt the nadir direction. STC has been designed so to have many optical elements common to both sub-channels. Also the image focal plane is common to the sub-channels and this permits the use of a single detector for the acquisition of the two images, i.e. one for each viewing direction. Considering the novelty of the design, conceived to sustain a harsh environment and to be as compact as possible, the STC unit is very complex. To obtain the most accurate 3D reconstruction of the Mercury surface, a camera model as precise as possible is needed, and an ad-hoc calibration set-up has been designed to calibrate the instrument both from the usual geometrical and radiometrical points of view and more specifically for the instrument stereo capability. In this context LSF estimation was performed with a new method applying a particular oversampling approach for the curve fitting to determine at first the entire calibration system transfer function and at the end the optical properties of the single instrument

Venus Observations by VIRTIS on ESA/Venus Express mission

International audienc

Venus Observations by VIRTIS on ESA/Venus Express mission

International audienc