The MAJIS (Moons And Jupiter Imaging Spectrometer) instrument on board the ESA JUICE (JUpiter ICy moon Explorer) mission is an imaging spectrometer operating in the visible and near-infrared spectral range from 0.50 to 5.55 μm in two spectral channels with a boundary at 2.3 μm and spectral samplings for the VISNIR and IR channels better than 4 nm/band and 7 nm/band, respectively. The IFOV is 150 μrad over a total of 400 pixels. As already amply demonstrated by the past and present operative planetary space missions, an imaging spectrometer of this type can span a wide range of scientific objectives, from the surface through the atmosphere and exosphere. MAJIS is then perfectly suitable for a comprehensive study of the icy satellites, with particular emphasis on Ganymede, the Jupiter atmosphere, including its aurorae and the spectral characterization of the whole Jupiter system, including the ring system, small inner moons, and targets of opportunity whenever feasible. The accurate measurement of radiance from the different targets, in some case particularly faint due to strong absorption features, requires a very sensitive cryogenic instrument operating in a severe radiation environment. In this respect MAJIS is the state-of-the-art imaging spectrometer devoted to these objectives in the outer Solar System and its passive cooling system without cryocoolers makes it potentially robust for a long-life mission as JUICE is. In this paper we report the scientific objectives, discuss the design of the instrument including its complex on-board pipeline, highlight the achieved performance, and address the observation plan with the relevant instrument modes.

MAJIS (Moons And Jupiter Imaging Spectrometer) is the VIS-IR imaging spectrometer of the ESA/JUICE mission that will explore the Jovian system. It covers the spectral range 0.5 to 2.35 μm and 2.26 to 5.56 μm using two channels. The MAJIS Optical Head (OH) consists in a TMA telescope shared between the two channels, as well as a slit and collimator, then a dichroic filter that splits the light between the channels, each one being equipped with its own grating and focusing lens. The same type of detector is used for both spectrometers (apart from the order sorting filter), being a 400 pixels × 508 spectels with 36 µm pitch. We will present the characterization of the OH performed at Leonardo Company at cold operational temperatures (from 110K to 150K). The test set-up with a specific emphasis of the Optical Ground Support Equipment (OGSE) used during that characterization campaign will be shortly described. Then, the main performances (spatial, spectral) of the OH will be presented and a comparison with the requirements will be provided.

•We describe the in detail the activities of planning and commanding for JIRAM.•We describe the observation strategy to construct robust observation timelines.•We describe the timing of JIRAM science observation.

In the frame of the Sentinel-5 mission, Leonardo is developing the Short-Wave Infrared Spectrometer (SWIR-SS), part of the UVNS instrument foreseen to be embarked on board of the MetOP-SG satellite. S5 instrument objective is to monitor the composition of Earth atmosphere by taking measurements of trace gases and aerosols impacting air quality and climate, providing daily coverage of Earth atmosphere at an unprecedented resolution. SWIR-SS baseline architecture is a pushbroom imaging spectrometer with two channels, [1589 divided by 1676] nm and [2304 divided by 2386] nm, with a spectral resolution of less than 0.25 mu At the object space is located a Slit-Homogenizer, a special component which guides the optical path across the slit in order to mitigate radiometric errors arising from scene heterogeneity. Its behaviour introduces an astigmatism which is corrected at collimator level by making use of a cylindrical lens. Light is then guided towards the dispersers and is focused onto the detector by the cameras lens. Pupil anamorphism, smile and keystone due to dispersers, immersed gratings, are corrected by using a prism and combining the distortion/lateral color of collimator and focusing cameras in both optical channels. A low pass filter at the dichroic splits the wavelengths, while, for each channel, two successive coatings on front and back faces of the prisms select the band and mitigate out-of-band straylight. The design has the purpose to keep the alignment of each subsystem simple, as no aberration compensations have been foreseen between collimator and focusing camera. It shows robustness, stability vs temperature and high optical quality.

The SPectral IMaging (SPIM) facility is a laboratory imaging VIS-IR spectrometer, operative in the INAF/IAPS laboratory in Rome. The facility is used as a laboratory support for the DAWN mission (to the asteroids Vesta and Cerere) and for the 2018 ExoMars mission (to Mars). This imaging spectrometer, which is the spare of the VIR spectrometer [1] on-board the DAWN spacecraft, is operative in the 0.22-5.1 spectral range. It is characterized by high spatial (38 μm) and spectral (2 nm in the VIS channel, 12 nm in the IR channel) resolution. The high spectral performances, combined with the high spatial resolution imaging capability of this instrument allow a very accurate laboratory investigation and characterization of numerous types of mineral and rock samples, both in powder and in slab form, and also of extraterrestrial samples down to a few tens of micrometers in size (such as for example Interplanetary Dust Particles).

The Dawn spectrometer (VIR) is a hyperspectral spectrometer with imaging capability. The design fully accomplishes Dawn’s scientific and measurement objectives. Determination of the mineral composition of surface materials in their geologic context is a primary Dawn objective. The nature of the solid compounds of the asteroid (silicates, oxides, salts, organics and ices) can be identified by visual and infrared spectroscopy using high spatial resolution imaging to map the heterogeneity of asteroid surfaces and high spectral resolution spectroscopy to determine the composition unambiguously. The VIR Spectrometer—covering the range from the near UV (0.25 μm) to the near IR (5.0 μm) and having moderate to high spectral resolution and imaging capabilities—is the appropriate instrument for the determination of the asteroid global and local properties. VIR combines two data channels in one compact instrument. The visible channel covers 0.25–1.05 μm and the infrared channel covers 1–5.0 μm. VIR is inherited from the VIRTIS mapping spectrometer (Coradini et al. in Planet. Space Sci. 46:1291–1304, 1998; Reininger et al. in Proc. SPIE 2819:66–77, 1996) on board the ESA Rosetta mission. It will be operated for more than 2 years and spend more than 10 years in space.

Introduction: Dawn is a NASA PI mission ( PI Christopher Russel of UCLA) of “Discovery” class[1], [2]. Dawn is also an international mission since NASA is supported by ASI ( Italian Space Agency) and DLR (German Space Agency) that are respectively in charge of providing the VIR spectrometers and the two cameras. Dawn Mission will be the first mission visiting the dwarf planet closer top the Earth, Ceres. Moreover Dawn will visit Vesta, that is also a very special body, being one of the few asteroids of the main belt that are supposed undergo to a differentiation. Therefore Vesta is an important example of intermediated objects that possibly undergo to a pristine differentiation, might be due to the decay of short lived radioactive elements. Only in situ observation will be able to disentangle the real nature of Vesta and Ceres. Dawn mission is perfectly suited to do that, thanks to its payload that will permit to study the geology (thanks to FC, the cameras), the geochemistry (thanks to the Grand, gamma spectrometer) and mineralogy (thanks to VIRMS, the imaging spectrometer). Here we will describe the VIR-MS characteristics. VIR-MS is an imaging spectrometer coupling high spectra and spatial resolution in the Visible (0.25-1 micrometer) and IR (0.95-5 micrometers) ranges. We have developed a spectrometer able to cover both Visible and IR regions of the spectrum combining these two spectral ranges in one instrument because diagnostic minerals have absorption bands in the Visible and NIR regions. We will describe VIR and its expected performances in terms of understanding both Vesta and Ceres. The Vir instrument. VIR will permit to study the mineralogical composition of the Ceres and Vesta surface, coupling high spectra and spatial resolution. Moreover VIR will help in understanding if the similarity between reflectance spectra of Vesta and HED meteorites and vestoids, possibly fragments of Vesta. To achieve these goals it is important to have a good spectral coverage: in fact diagnostic minerals show absorption bands in the Visible and NIR regions. Determination of the mineral composition of surface materials in their geologic context is a primary Dawn objective. The nature of the solid compounds of the asteroids (silicates, oxides, salts and ices) can be identified by visual and infrared spectroscopy using high spatial resolution imaging to map the heterogeneity of asteroid surfaces and high spectral resolution spectroscopy to determine the composition unambiguously. Medium resolution spectral images in the visible and infrared ranges allow us to have information on the mineralogical composition of the asteroid surface. Spectral resolution added to spatial resolution is needed to have important information on surface geology, so that will be possible the identification of mineralogical provinces, obtaining compositional maps. Such maps will provide information on the relationship between global and local spectral characteristics. Calibration Procedure. Vir instrument has a complex internal calibration unit consisting in two spectral lamps that were calibrated on ground [3]. The two lamps can be turned on independently to test the performances of the instrument in the Vis and IR range. During the first activities of the commissioning the internal calibration unit has been used in order to check the performances of the instrument. In the figures 1a and 1b below we show the data acquired in flight: high spatial and high spectral profile of the calibration procedure. Each calibration session is constituted by 7 steps. At step 4 the IR calibration lamp is switched on and 5 frames acquired. At the next step the IR lamp is switched off, and the VIS calibration lamp is switched on. In this way it is possible to check the integrity of both the detectors.

The Italian drill “DEEDRI” is going to be the lander based sample acquisition system for the Mars Surveyor Program of the Mars Sample Return mission. DEEDRI is capable to collect core/sand sample of the martian soil down to 50 cm in depth. The MA_MISS experiment belongs to the DEEDRI system and it will be dedicated to observe the wall of the excavated hole in terms of infrared spectral reflectance in the range 0.8–2.8 μm. The spectral sampling is about 20 nm while the spatial sampling is 100 μm over the target. The optical window of MA_MISS is placed very close to the drill tip so that the target view to be observed can span from the soil down to 50 cm. The proximity optics and electronics of MA_MISS have to be very miniaturized since they will be collocated inside the drill tool in a very limited volume of about 25 mm in diameter. On the other side the main electronics will be on the lander and it will communicate through an interface based on slip rings devices. MA_MISS can acquire in different observation modes. The images are scanned by moving the DEEDRI itself. One image ring is built up by acquiring contiguous images of the MA_MISS slit. The study of the Martian subsurface will provide important constraints on the nature, timing and duration of alteration and sedimentation processes on Mars, as well as on the complex interactions between the surface and the atmosphere. This study will permit to infer the history of erosion, transport and deposition of loose material. Alteration processes can dominate the mineralogy of the Martian surface: it will be essential to study the mineralogy of deeper layers, where a more limited alteration took place. MA_MISS can provide very important scientific return from the subsurface of Mars along with a selection criteria for the samples collection.