In October 2023, a spectrograph has been permanently installed at the Skibotn Observatory (Norway) in order to regularly monitor the auroral spectrum between ~ 400 and 700 nm with a time resolution of 30 seconds. Using a 300 lines/mm grating and a slit of 100 nm width, the wavelength resolution is approximately of 0.3 nm. The instrument is pointing field-aligned.The characteristics of the instrument will be provided as well as examples of spectra obtained during quiet, moderate and strong geomagnetic conditions. A relative flux calibration is currently under way and will be discussed as well. This will allow the computation of line ratios or a comparison with synthetic spectra obtained using kinetic transport codes such as e.g. Transsolo. Both approaches will provide an estimate of the precipitating fluxes (for electrons but also possibly for protons).Later on we aim to provide a database of low resolution auroral spectra accessible to the community, which will nicely complement data obtained with the new EISCAT_3D radar located a few kilometers from the observatory and data from the other optical instruments located at the observatory itself. We will also consider the possibility to obtain higher resolution spectra using a 1800 lines/mm grating during specific requested campaigns.This project is a joint collaboration between BIRA-IASB (Belgium), IPAG (France) and UiT (Norway).

VenSpec is a spectrometer suite on board ESA's EnVision mission to planet Venus, due for launch in November 2031. VenSpec consists of three spectrometers, VenSpec-M, VenSpec-U and VenSpec-H. VenSpec-H stands for Venus Spectrometer with High resolution. It operates in the near-infrared wavelength range between 1.15 and 2.5 mu m and it aims at mapping the near surface atmosphere during the night and the atmosphere above the cloud deck during the day. More specific, VenSpec-H will measure gases related to volcanism and surface changes on Venus. It will perform its measurements by means of nadir observations. In this paper an overview is given of the main design requirements, followed by a description of the design activities performed during the feasibility study (phase A) and the preliminary definition (phase B1) of the instrument, including mathematical modeling and analysis, and prototyping. Focus is put on the optical working principle of the instrument, where an echelle grating, used as diffractive element, is combined with an inventive combination of filters for spectral band selection. The design and development of VenSpec-H is done in a consortium under Belgian management and with important contributions from Belgian, Swiss, Spanish, and Dutch research institutes, universities, and industrial partners.

Onboard the EnVision spacecraft, there will be a suite of three spectrometers, VenSpec. One of these is called VenSpec-H where the H stands for high spectral resolution. Its scientific objectives consist of measuring variations of minor species' abundances in the atmosphere of Venus. H2O, SO2, CO, and OCS will be measured to characterize the potentially ongoing volcanic activity. These observations will allow us to understand both the importance of volatiles in volcanic activity on Venus and their effect on cloud maintenance and dynamics. VenSpec-H will measure these molecules in nadir viewing geometry, in infrared transparency windows of Venus' nightside to probe the troposphere, and in infrared spectral ranges on the dayside to measure the mesosphere. The scientific requirements enabling our scientific objectives will be demonstrated. The molecular vertical profiles, the aerosols' model, and the CO2 continuum contribution were established based on the literature for the different spectral windows. This enabled us to determine the spectral bands, their bandwidth, and the resolving power necessary for our purposes. Along the way, we identified possible improvements and science avenues. Some of them impact the instrument design, such as the need for polarimetric measurements. Others are related to remaining uncertainties in the model and laboratory measurements that will complement the investigation. This has been presented as a poster at the SPIE Optical Engineering + Applications Conference in August 2024 in San Diego, California, United States.

In this work, we analyzed simultaneous observations of solar particles and solar electromagnetic ultraviolet (UV) radiation during solar events from January 2024 to May 2024. Measurement campaigns to study the effects of space radiation on the terrestrial atmosphere were conducted in the framework of the project BIOSPHERE. We show the results of the campaign in Brussels from 1 January 2024 to 31 March 2024, during which several solar energetic particle (SEP) events were observed by the spacecraft GOES and OMNI, together with two big geomagnetic storms in March 2024 and May 2024 associated with solar eruptions. The last two events combine the arrival of a SEP event with a geomagnetic storm. On 11 May 2024, the biggest geomagnetic storm for the last 20 years was observed. These events enabled us to identify effects due to UV, solar particles, and geomagnetic storms. The impact of these events on the terrestrial radiation belts, illustrated by satellite observations like PROBA-V/EPT and on the atmospheric ozone using AURA/MLS is demonstrated. For the measurement campaign, muon and neutron monitors showed a Forbush decrease only during the geomagnetic storm at the end of March 2024 and in May 2024. Complemented by a simulation of radiation effects on the ionization rate of the atmosphere as a function of the altitude, the extensive range of different observations available during this measurement campaign demonstrated that SEP and geomagnetic storms due to solar eruptions had very different effects on the terrestrial atmosphere. The geomagnetic storms mainly modified the energetic electrons trapped in the space environment of the Earth and affected the ionization of the atmosphere above 60 km. They also modified the cosmic ray injections, mainly at high latitudes, creating Forbush decrease for the most intense ones. SEP events injected energetic protons in the atmosphere that could penetrate deeper in the atmosphere because they had more energy than the electrons. They could impact ozone, mainly at high altitude in the thermosphere. Solar activity variation associated with the rotation of the solar active regions in 27 days modulated UV. The measurements of these electromagnetic and particle radiations are crucial because they have important health implications.

The MAR (Modèle Atmosphérique Régional) is a regional climate model used for weather forecasting and climate studies over several continents, including polar regions. To simulate how solar radiation and Earth's infrared radiation propagate through the atmosphere and drive climate, MAR uses the Morcrette radiation scheme. Last updated in the 2000s, this scheme is no longer maintained and lacks the flexibility to add new capabilities, such as computing high-resolution spectral fluxes. This paper presents version 3.14 of MAR, an update that allows MAR to run with ecRad, the latest radiation scheme provided by the European Centre for Medium-Range Weather Forecasts (ECMWF). Operational in the ECMWF's Integrated Forecasting System (IFS) since 2017, ecRad was designed with modularity in mind and is still in active development. We evaluate the updated MAR by comparing its outputs over 2011–2020 for Belgium to gridded data provided by the Royal Meteorological Institute of Belgium (RMIB) and by the EUMETSAT Satellite Application Facility on Land Surface Analysis. Several sensitivity experiments have been carried out to find the configuration achieving the most balanced radiative budget, as well as to demonstrate that the updated MAR is better equipped to achieve such a balance. Moreover, a MAR simulation running ecRad with high-resolution ecCKD gas-optics models has been conducted to produce spectral shortwave fluxes, which are compared to ground-based spectral measurements captured by the Royal Belgian Institute for Space Aeronomy at Uccle (Belgium; 50.797° N, 4.357° E) in the 280–500 nm range from 2017 to 2020. Finally, as a first application of spectral shortwave fluxes computed by MAR running with ecRad, a method for predicting UV indices is described and evaluated.

This poster contribution will highlight recent advancements in the European Partnership on Metrology (EPM) project BIOSPHERE (https://euramet-biosphere.eu/), which focuses on developing innovative tools, methodologies, and a metrological framework to assess the mutual impact of cosmic rays and biologically active UV radiation on the Earth’s biosphere. Both electron precipitations of extraterrestrial origin and energetic bursts of protons released from the Sun during coronal mass ejections have the potential to affect lower stratosphere ionization and fuel catalytic cycles responsible for ozone depletion. Since the ozone layer serves as the planet’s primary defense against harmful solar UV radiation, its degradation leads to an increased influx of biologically active UV radiation, with far-reaching consequences for human health, terrestrial and marine ecosystems, and global biogeochemical cycles. While the role of solar UV radiation in ionizing chlorine-containing anthropogenic molecules and driving ozone depletion is well established, the influence of cosmic rays remains poorly understood. Bridging this knowledge gap demands a concerted, interdisciplinary effort, integrating metrology, cutting-edge satellite observations, advanced ground-based remote sensing, and in situ measurements with expertise in atmospheric chemistry, radiation physics, environmental science, and biology. To assess the impact of these extraterrestrial radiation fields on the biosphere, the EPM project BIOSPHERE aims to provide traceable metrological data on cosmic ray fluxes, solar UV radiation at the Earth's surface and the total ozone column, which are crucial for assessing the role of cosmic rays in atmospheric dynamics. For this purpose, dedicated instruments have been developed and characterized to determine the dependence of secondary cosmic rays on primary cosmic rays (galactic cosmic rays, solar particle events) and atmospheric parameters. For the first time, fundamental data on the interaction of low-energy cosmic ray-induced electrons with relevant atmospheric gases of both natural and anthropogenic origin will be determined. This project also investigates - for the first time - the mutual effects of combined radiation fields (protons/gamma rays and solar UVB radiation) on human skin and blood cell lines in simulated extreme exposures, some of which mimic the effects of large solar particle events associated with ozone depletion and resulting ground-level enhancements. In this contribution, key results will be presented, including how overlying atmosphere affects cosmic radiation fluxes measured at ground level, how solar particle events and geomagnetic storms affect stratospheric and mesospheric ozone concentrations, and the overall ionization of the atmosphere. Further, this research will explore the complex interactions between solar radiation and cosmic radiation at the cellular level, emphasizing how these radiations can work in concert to affect human cell biology, including cell viability, stress responses, DNA damage, and ultimately genomic instability in skin fibroblasts, lymphocytes, monocytes, and keratinocytes. These results will pave the way and promote a better understanding of the complex ionization landscape in the atmosphere and radiation environment on Earth, and its potential impact on the ozone shield and human health. They will also aid in the discovery of biological targets that will allow the development of a therapeutic strategy aimed at mitigating the harmful effects of combined radiation exposure.

Past and present Mars orbiters have been able to provide great information on Mars surface and atmosphere, focusing mostly on targeted high resolution measurements but lacking continuous global coverage. However, Mars atmospheric phenomena (clouds and dust storms in particular) and space weather environment require continuous, simultaneous, global observations to fully understand the dynamic variability and extension of meteorological and environmental conditions at Mars [Montabone, 2021]. In the next decade, spacecrafts monitoring Mars will embark on a new generation of instruments.In a collaboration between the Royal Belgian Institute for Space Aeronomy (BIRA-IASB) and the Lambda-X company, an instrument for future Martian orbiter missions, MIDIM is being developed. The “Mars Imager for Dust and Ice clouds Monitoring” will be a multispectral band UV imager able to monitor dust and ice clouds.Dust and ice clouds are key compounds in the Martian climate as they modulate the dynamical and thermal structure of the atmosphere. They absorb and scatter sunlight, which can result in local warming or cooling of the atmosphere. A constant monitoring of aerosols around Mars would help us to assess the physical processes that control the onset, growth and decay of dust storms, the interannual variability of global dust storms, the global budget of dust and its evolution over time, as these processes are not yet fully understood in the martian atmosphere [Kahre, 2024]. The impact on the water ice cycle also needs to be better constrained.The MIDIM imager will have an extended field of view covering a large portion of Mars, depending on the orbit of the spacecraft. It will be suited for high altitude or stationary orbits. The instrument design will be partly based on the heritage of the NOMAD/UVIS instrument [Patel et al., 2017] on board ExoMars Trace Gas Orbiter, using the same CCD camera, as well as in state-of-the-art CubeSat compatible optical design solutions [Schifano 2022]The NOMAD/UVIS dataset is used in this work to assess the science requirements related to the objectives of this instrument [Willame et al. in prep, Willame et al. 2017] In the poster, we will present our progress about the design and preliminary studies of the MIDIM development. ReferencesKahre (2024), Dust on Mars. Oxford Research Encyclopedia of Planetary Science, Oxford University Press, article id. 119.Montabone (2021), A Paradigm Shift in Mars Meteorology. EPSC 2021, 625.Patel MR et al. (2017) NOMAD spectrometer on the ExoMars trace gas orbiter mission: part 2—design, manufacturing, and testing of the ultraviolet and visible channel. Appl Opt, AO 56:2771–2782Schifano L. et al. (2022) Freeform Wide Field-of-View Spaceborne Imaging Telescope: From Design to Demonstrator. Sensors 2022, 22, 8233.Willame et al. in prep. Dust and ice cloud retrieval from NOMAD/UVIS.Willame et al. (2017). Retrieving cloud, dust and ozone abundances in the Martian atmosphere using SPICAM/UV nadir spectra Planet. Space Sci., 2017. 142: p. 9-25.

The MAJIS (Moons and Jupiter Imaging Spectrometer) instrument is an imaging spectrometer on-board the JUICE (JUpiter ICy moons Explorer) spacecraft. MAJIS covers the spectral range from 0.5 to 5.54 mu m with two channels [visible-near infrared (VISNIR) and IR]. A comprehensive campaign of on-ground MAJIS calibration was conducted in August and September 2021 in the IAS (Institut d'Astrophysique Spatiale, CNRS/Universit & eacute; Paris-Saclay) facilities. In this article, we present the results relevant for the radiometric calibration of MAJIS. Due to the specific characteristics of the MAJIS detectors (H1RG from Teledyne), an extensive detector characterization campaign was implemented for both the VISNIR and IR detectors before integration so as to validate readout procedures providing precision and accuracy. The characterization also provided critical information on linearity and operability as a function of the integration time and operating temperature. The radiometric calibration of the integrated MAJIS instrument focused on the determination of the instrument transfer function in terms of DN output per unit of radiance for each MAJIS data element as a function of its position in the field of view of MAJIS and its central wavelength. The radiometric calibration of the VISNIR channel required a specific procedure due to stray light at short wavelengths. Observations of an internal calibration source during calibration and after launch (April 14, 2023) showed that there were minor changes in both the VISNIR and IR channels. The instrument transfer functions to be used in flight have been updated on this basis.

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.

The European Partnership on Metrology (EPM) joint research project BIOSPHERE aims to develop the necessary instrumentation, methods, and measurement infrastructure to assess how the increasing ionization of the atmosphere, caused by extraterrestrial radiation fields (cosmic rays and solar UV radiation) and amplified by anthropogenic emissions, affects the human and ecological health of our planet.Both electron precipitations of extraterrestrial origin and energetic bursts of protons released from the sun during solar flares or coronal mass ejections have the potential to affect lower stratosphere ionization and interfere with catalytic ozone depletion reactions. This can lead to an increase of the biologically active UV radiation flux, with significant implication for ecosystems, plants and human health, like cancers and cellular dysfunctions. To estimate the impact of these extraterrestrial radiation fields on the biosphere, the EPM project BIOSPHERE will provide traceable metrological data on cosmic ray fluxes, UV solar radiation at the earth surface, and the total ozone column which are key to assessing the role of cosmic rays in the atmospheric dynamics. For this purpose, dedicated instrumentation for determining the dependence of secondary cosmic rays (SCRs) on primary cosmic rays (galactic cosmic rays, solar particle events) and atmospheric parameters (e.g., temperature, density and aerosol concentration) has been developed and characterized. This instrumentation measures the SCR flux rate during measurement campaigns, side-by-side with spectra of UV solar radiation at ground level and total atmospheric ozone, with the aim of identifying and correlating changes of extraterrestrial cosmic radiation (revealed with SCR fluxes increased) with changes in atmospheric parameters (ground-based UV radiation, total ozone column). As the cosmic ray flux measured at ground level is influenced by the overlying atmosphere, a metrological methodology is currently being developed to correlate SCR flux rates with temperature and pressure. This method will also help to quantify the rates of ionizing particles in the lower stratosphere that can interfere with catalytic ozone depletion reactions. Traceable measurements of cosmic ray fluxes, UV radiation spectrum and ozone column are being carried out in measurement campaigns at four European sites. We will present here the instrumentation developed, the instrumental methodologies and the results of the first two campaigns.

The European Partnership on Metrology (EPM) joint research project BIOSPHERE investigates how the increasing ionization of the atmosphere, caused by extraterrestrial radiation fields (cosmic rays and solar UV radiation) and amplified by anthropogenic emissions, affects the human and ecological health of our planet. One main aspect is how these extraterrestrial radiation fields impact the stratospheric ozone (enforced depletion), resulting in an increase of Ultraviolet (UV) radiation on the ground.To assess the influence of extraterrestrial radiation fields on atmospheric parameters and on solar UV radiation on the Earth surface, BIOSPHERE organizes four measurement campaigns with colocated SCR (Secondary Cosmic Rays) measurements (revealing the cosmic rays events) and solar UV radiation measurements, in GHI (global horizontal irradiance) and DNI (direct-sun normalized irradiance) geometries of observation. From the DNI UV radiation measurements we extract some atmospheric parameters: the total ozone column (TOC) in dobson units (DU) and the aerosol optical depth (AOD) for the UV wavelength range (290 nm - 400 nm).The measurement campaigns took place at Athens (near urban site) in summer, in Brussels (urban site) in winter, in Milesovka (Czech Republic, rural mountain site) in spring/summer and will take place in Lindenberg (North-East Germany, rural flatland site) in autumn.In addition to the correlation study confronting SCR measurements to TOC, AOD and UV measurements, we focus here on the quality of the UV radiation and atmospheric parameters’ measurements during the first campaigns: UV radiation (GHI) and especially the UV index from spectroradiometers (array spectrometers: Gigahertz-Optik BTS2048-UV-S-WP, Bentham DTMc300 double monochromators) are compared to measurements from UVB pyranometers and a multi-channel filters radiometer (GUV-511 from BIOSPHERICAL Inc.) on the same site. TOC and AOD measurements done with UV DNI spectral measurements with an array spectrometer (Gigahertz-Optik BTS-Solar based on BTS2048-UV-S-WP) are compared to Brewer and photometer measurements done on geographically close sites. This survey analyzes the measurement differences, considering the instrumentation itself, the measurement retrieval procedures, and the spatial heterogeneity of the atmospheric parameters when the measurements that are compared to each other are not done at the same site.

Uvsq-Sat NG is a French 6U CubeSat (10 × 20 × 30 cm) of the International Satellite Program in Research and Education (INSPIRE) designed primarily for observing greenhouse gases (GHG) such as CO2 and CH4, measuring the Earth’s radiation budget (ERB), and monitoring solar spectral irradiance (SSI) at the top-of-atmosphere (TOA). It epitomizes an advancement in CubeSat technology, showcasing its enhanced capabilities for comprehensive Earth observation. Scheduled for launch in 2025, the satellite carries a compact and miniaturized near-infrared (NIR) spectrometer capable of performing observations in both nadir and solar directions within the wavelength range of 1100 to 2000 nm, with a spectral resolution of 7 nm and a 0.15° field of view. This study outlines the preflight calibration process of the Uvsq-Sat NG NIR spectrometer (UNIS), with a focus on the spectral response function and the absolute calibration of the instrument. The absolute scale of the UNIS spectrometer was accurately calibrated with a quartz-halogen lamp featuring a coiled-coil tungsten filament, certified by the National Institute of Standards and Technology (NIST) as a standard of spectral irradiance. Furthermore, this study details the ground-based measurements of direct SSI through atmospheric NIR windows conducted with the UNIS spectrometer. The measurements were obtained at the Pommier site (45.54°N, 0.83°W) in Charentes–Maritimes (France) on 9 May 2024. The objective of these measurements was to verify the absolute calibration of the UNIS spectrometer conducted in the laboratory and to provide an extraterrestrial solar spectrum using the Langley-plot technique. By extrapolating the data to AirMass Zero (AM0), we obtained high-precision results that show excellent agreement with SOLAR-HRS and TSIS-1 HSRS solar spectra. At 1.6 μm, the SSI was determined to be 238.59 ± 3.39 mW.m−2.nm−1 (k = 2). These results demonstrate the accuracy and reliability of the UNIS spectrometer for both SSI observations and GHG measurements, providing a solid foundation for future orbital data collection and analysis.

EnVision is ESA's upcoming mission to Venus with a launch scheduled in 2031. One of the payloads on board is the VenSpec suite,(1) containing three spectrometer channels, one of which is VenSpec-H. VenSpec-H (Venus Spectrometer with High resolution) performs absorption measurements in the atmosphere of Venus in four near-infrared spectral bands. VenSpec-H is developed under Belgian management and builds on heritage from instruments on Venus-Express and TGO. Techniques used in these precursor instruments are improved and complemented with new technologies to comply with the scientific goals of the EnVision mission. The operating wavelength range (1.15 - 2.5 mu m) imposes stringent temperature requirements on the instrument to make nightside measurements below the Venus clouds possible. Most importantly, the spectrometer's optical components are held in a separate cold section inside the instrument, cooled down to -45 degrees C, to remove thermal background from the signal. To avoid heat dissipation close to the spectrometer optics, the electronic boards are kept in a separate box. Besides that, some mechanisms, placed in the warmer part of the instrument at the entrance or exit of the cold section, had to be developed: a turn window unit to protect the interior of the instrument during the aerobraking phase of the mission, a filter wheel mechanism to select the spectral bands of interest, and an integrated detector-cooler-assembly to register the spectra. Some passive optical elements in the spectrometer had low technological readiness at the start of the project. One of them is a freeform corrector plate, used to compensate for aberrations introduced in the system by a parabolic mirror. This device is developed by the Brussels Photonics lab of VUB (Brussels) using a supply chain with shape adaptive corrective polishing and dedicated metrology. Another is the echelle grating, used to disperse the incoming light into its spectral components, which is built by AMOS. Both devices are highlighted in this article.

INSPIRE-SAT 7 is a French 2-Unit CubeSat primarily designed for Earth and Sun observations. This mission is part of the International Satellite Program in Research and Education (INSPIRE). This satellite will be deployed in Low Earth Orbit (LEO) in 2023 as the first step of the so-called ‘Terra-F’ constellation that will provide spatio-temporal resolution for Earth Energy Imbalance (EEI) measurements. This new scientific and technological pathfinder CubeSat mission (INSPIRE-SAT 7) is equipped with various channels on all sides. Among them: the Total Solar Irradiance Sensor (TSIS) payload, the Ultra-Violet Sensor (UVS) using a new generation of solar blind detectors designed to monitor the integrated Solar Spectral Irradiance (SSI) in the Hertzberg continuum, and the Earth Radiative Sensor (ERS) payload, designed to measure some Earth’s Radiative budget (ERB) components such as the outgoing short and long wave radiation at the top-of-the atmosphere for climate change studies. The Belgian Radiometry Characterization Laboratory (B.RCLab) of the Royal Belgian Institute for Space Aeronomy (BIRA-IASB) is the partner responsible for the pre-flight absolute calibration and radiometric characterization of INSPIRE-SAT7 TSIS and UVS payloads. In this work we will first describe the INSPIRE-SAT7 concept, design, scientific and operational objectives. We will then present B.RCLab facilities along with its radiometric characterization benches, including the absolute calibration capabilities and its traceability. Finally, the main results of the INSPIRE-SAT7 pre-flight calibration campaign, which took place in November 2022, will be presented. These results allowed to calculate the sensors on-orbit calibration coefficients that are crucial to perform traceable absolute EEI measurements. A radiometric comprehensive uncertainty budget will be presented along the sensors’ calibration coefficients.

When developing new astronomical instruments, there is a need to perform the characterization of their individual components, especially the detectors, to ensure that their performances comply with the scientific objectives of the instrument. A visible-near infrared (VIS-NIR) facility was developed for the absolute and relative radiometric characterization of space-based detectors at the Royal Belgian Institute for Space Aeronomy (BIRA-IASB). The facility operates from 0.4 to 2.65 mu m in an ISO-5 environment. It offers a tunable monochromatic flux with a high level of straylight rejection (10 (- 8)) and 2% uniformity, over a four-decade range of intensity with adjustable bandwidth. Latency measurements are also possible. Thermalization is offered within a precision of 7 mK between 50 K and 382 K. The ultimate vacuum level of the detector chamber is below 10( - 6) mbar. A robust security system avoids both reaching temperatures outside the operational range of the detector and its electronics, and contamination due to vacuum loss. The facility was already used to characterize the VIS-NIR detectors of the Moons And Jupiter Imaging Spectrometer (MAJIS), one of the instruments on board the Jupiter ICy Moons Explorer (JUICE). The versatility provided by the VIS-NIR facility allows its use for the characterization of other astronomical detectors.(c) The Authors.

The JUICE (JUpiter ICy moons Explorer) mission by ESA aims to explore the emergence of habitable worlds around gas giants and the Jupiter system as an archetype of gas giants. MAJIS (Moons and Jupiter Imaging Spectrometer) is the visible to near-infrared imaging spectrometer onboard JUICE which will characterize the surfaces and exospheres of the icy moons and perform monitoring of the Jupiter atmosphere. The launch is scheduled for 2023 with the first MAJIS observations inside the Jovian system occurring more than 8 years later. The MAJIS optical head is equipped with two Teledyne H1RG detectors, one for each of the two spectrometer channels (VIS-NIR and IR). This paper describes the characterization of the VIS-NIR Focal Plane Unit. These detectors will be operated in a non-standard way, allowing near/full-frame retrieval over short integration times (<< 1 sec) while maintaining good noise performance. After a quick description of the characterization strategy that was designed to evaluate the performances of the VIS-NIR detector according to the MAJIS operational specifications, the paper will address the data analyses and the main results of the characterization campaign. The major performance parameters such as dark current, linearity, noise, quantum efficiency, and operability will be presented and compared with the requirements.

We present measurement protocols of performances, test and calibrations of new compact solid-state photodetectors based on β-Ga2O3 oxides, and optimized for the UVC. They present reduced dark currents, permitting room temperature operation suppressing need for a cooling system (mass and power savings) and avoiding cold surfaces that traps environmental contamination. Detectors' response peak around 215-220 nm with a bandpass of 30 nm, allowing to observe the UVC wavelength band responsible of ozone creation in the stratosphere (Herzberg continuum, 200-242 nm) and to achieve solar-blindness for wavelengths above 250 nm. Other key assets of β-Ga2O3 detectors are their radiation hard properties (longer lifetime), and possible sensitivity (several hundreds mA/W at -5 V) that allows operation at lower voltages (reduced power), a key asset for Space applications. These detectors, evaluated, tested and calibrated, will be integrated on the INSPIRE-7 nanosatellite to be launched in 2023.

INSPIRE-SAT 7 is a French 2-Unit CubeSat (11.5 × 11.5 × 22.7 cm) primarily designed for Earth and Sun observation. INSPIRE-SAT 7 is one of the missions of the International Satellite Program in Research and Education (INSPIRE). Twice the size of a 4 × 4 Rubik’s Cube and weighing about 3 kg, INSPIRE-SAT 7 will be deployed in Low Earth Orbit (LEO) in 2023 to join its sister satellite, UVSQ-SAT. INSPIRE-SAT 7 represents one of the in-orbit demonstrators needed to test how two Earth observation CubeSats in orbit can be utilized to set up a satellite constellation. This new scientific and technological pathfinder CubeSat mission (INSPIRE-SAT 7) uses a multitude of miniaturized sensors on all sides of the CubeSat to measure the Earth’s energy budget components at the top-of-the-atmosphere for climate change studies. INSPIRE-SAT 7 contains also a High-Frequency (HF) payload that will receive HF signals from a ground-based HF transmitter to probe the ionosphere for space weather studies. Finally, this CubeSat is equipped with several technological demonstrators (total solar irradiance sensors, UV sensors to measure solar spectral irradiance, a new Light Fidelity (Li-Fi) wireless communication system, a new versatile telecommunication system suitable for CubeSat). After introducing the objectives of the INSPIRE-SAT 7 mission, we present the satellite definition and the mission concept of operations. We also briefly show the observations made by the UVSQ-SAT CubeSat, and assess how two CubeSats in orbit could improve the information content of their Earth’s energy budget measurements. We conclude by reporting on the potential of future missions enabled by CubeSat constellations.

Recent solar physics missions have shown the definite role of waves and magnetic fields deep in the inner corona, at the chromosphere-corona interface, where dramatic and physically dominant changes occur. HiRISE (High Resolution Imaging and Spectroscopy Explorer), the ambitious new generation ultra-high resolution, interferometric, and coronagraphic, solar physics mission, proposed in response to the ESA Voyage 2050 Call, would address these issues and provide the best-ever and most complete solar observatory, capable of ultra-high spatial, spectral, and temporal resolution observations of the solar atmosphere, from the photosphere to the corona, and of new insights of the solar interior from the core to the photosphere. HiRISE, at the L1 Lagrangian point, would provide meter class FUV imaging and spectro-imaging, EUV and XUV imaging and spectroscopy, magnetic fields measurements, and ambitious and comprehensive coronagraphy by a remote external occulter (two satellites formation flying 375 m apart, with a coronagraph on a chaser satellite). This major and state-of-the-art payload would allow us to characterize temperatures, densities, and velocities in the solar upper chromosphere, transition zone, and inner corona with, in particular, 2D very high resolution multi-spectral imaging-spectroscopy, and, direct coronal magnetic field measurement, thus providing a unique set of tools to understand the structure and onset of coronal heating. HiRISE’s objectives are natural complements to the Parker Solar Probe and Solar Orbiter-type missions. We present the science case for HiRISE which will address: i) the fine structure of the chromosphere-corona interface by 2D spectroscopy in FUV at very high resolution; ii) coronal heating roots in the inner corona by ambitious externally-occulted coronagraphy; iii) resolved and global helioseismology thanks to continuity and stability of observing at the L1 Lagrange point; and iv) solar variability and space climate with, in addition, a global comprehensive view of UV variability.