ABSTRACT
Near-infrared spectroscopy has become a well-known remote sensing technique for the surface characterization of planetary objects. Among them, Mars was observed in the past by three imaging spectrometers from orbit. The Infrared Spectrometer/SuperCam instrument performs near-infrared spectroscopy from the martian surface for the first time, with a 1.15 mrad field of view, in the 1.3 µm-2.6 µm range, enabling the identification of a variety of mafic and altered minerals. Before integration aboard the rover, the spectrometer underwent a calibration campaign. Here, we report the radiometric and linearity responses of the instrument, including the optical and thermal setups used to perform them over its nominal range of operations, in terms of instrument detector temperatures and spectral range. These responses were constrained by accuracy requirements (20% in absolute radiometry, 1% in relative). The derived instrument transfer function fits within these requirements (<15% in absolute and <0.8% in relative) and shall be used to calculate the expected instrumental signal-to-noise ratio for typical observation scenarios of mineral mixtures expected to be found in the Jezero crater, and ultimately to retrieve the spectral properties of the regions of interest observed by the rover.
ABSTRACT
Ionometric determinations indicate that nitrate accumulation does not reach very high levels in pears, apples, cherries and peaches. The examination of samples taken from various experimental plots has shown some variations in nitrate contents of fruits, in relation with the uptake by trees of nitrogen, magnesium and calcium. Other factors liable to affect the nitrate content of fruits have also been examined: maturation level of fruits, application of a growth retardant, types of cultivars. Because of their low nitrate content, the fruits here studied are representative of a class of products well suited to human food requirements.
