On the NASA 2020 rover mission to Jezero crater, the remote determination of the texture, mineralogy and chemistry of rocks is essential to quickly and thoroughly characterize an area and to optimize the selection of samples for return to Earth. As part of the Perseverance payload, SuperCam is a suite of five techniques that provide critical and complementary observations via Laser-Induced Breakdown Spectroscopy (LIBS), Time-Resolved Raman and Luminescence (TRR/L), visible and near-infrared spectroscopy (VISIR), high-resolution color imaging (RMI), and acoustic recording (MIC). SuperCam operates at remote distances, primarily 2–7 m, while providing data at sub-mm to mm scales. We report on SuperCam’s science objectives in the context of the Mars 2020 mission goals and ways the different techniques can address these questions. The instrument is made up of three separate subsystems: the Mast Unit is designed and built in France; the Body Unit is provided by the United States; the calibration target holder is contributed by Spain, and the targets themselves by the entire science team. This publication focuses on the design, development, and tests of the Mast Unit; companion papers describe the other units. The goal of this work is to provide an understanding of the technical choices made, the constraints that were imposed, and ultimately the validated performance of the flight model as it leaves Earth, and it will serve as the foundation for Mars operations and future processing of the data.

The microchannel plate (MCP) has been used for decades as a photon, electron and atoms detector in most of the space instruments dedicated for X-rays, energetic neutral atoms and charged particle imaging. The deep-space missions, as near-future ESA Jupiter Icy moon Explorer (JUICE) mission, expect very low temperature conditions on the destination orbit. Since instruments are usually calibrated on the ground under the “room” temperature, it is very important to know the variation of the detectors’ properties with temperature. The resistance and the gain of MCP detectors, dedicated for the Jovian Energetic Neutrals and Ions (JENI) sensor as part of the Particle Environment Package (PEP) instrument onboard JUICE, were measured as a function of temperature at INTRASPEC TECHNOLOGIES, Toulouse, France over the temperature range of − 50 to + 50 °C and at the CALIPSO-3 facility of the Institut de Recherche en Astrophysique et Planétologie (IRAP), Toulouse, France over the temperature range of − 25 to + 25 °C using samples from PHOTONIS France and PHOTONIS USA. Depending on how the resistance of an MCP detector behaves with temperature, it is possible to properly size a high voltage source or, conversely, to choose a glass technology according to the resistance range required for the MCP detector or their minimum operational bias strip current in relation to the extracted current due to the particle counts. Moreover, since the environment of Jupiter is very severe, the sensors of the PEP package instrument onboard JUICE will operate in the presence of high-energy particles which represent a noise source for them despite the shielding of the instrument against radiation. In particular, the background radiation in the Jovian environment represents a crucial issue for the JENI MCP detectors whose gain can be degraded prematurely if too much of charge is extracted from them. Our measurements show that the gain variation of JENI MCP detectors depends on their characteristics, which is an important result that can be used to optimize their gain performance and lifetime. We also show that the resistance of the JENI MCP detectors increases when the temperature decreases and is influenced by the MCP-resistive heating.

Space-based instruments for detection of photons, plasma, and energetic neutral atom imaging include electron multiplier detectors that are subject to increased transient noise, long-term degradation, and even potential failure due to the substantial fluxes of high-energy particles that penetrate the instrument in the space environment. The most commonly used electron multiplier detectors are multi-channel plates (MCP). These detectors are sensitive not only to the incident energetic charged particles themselves but also to the final end-product energy deposited by energetic electrons, ions, and X-rays/gammas. The resulting radiation-induced background noise can potentially contaminate the science signal. This issue constitutes undoubtedly one of the main challenges together with the radiation hardness of the electronics for particle instruments onboard future missions to Jupiter like the European Space Agency (ESA) Jupiter ICy moon Explorer (JUICE), and requires dedicated and innovative radiation mitigation techniques (e.g., multiple coincidence, anti-coincidence) far beyond the simple passive shielding techniques commonly used to protect electronics and other subsystems against total ionizing dose (TID). The accurate response (i.e., efficiency) of MCP detectors against high-energy particles is, however, not well known, with limited estimates available in the literature. This makes it complicated in particular to reliably predict the signal–noise ratio (SNR) of the instrument, and, hence, ensure that the instrument will return useful scientific data when operated in the Jovian magnetosphere. We describe and report in the present paper the results of an experiment in which we measured the response of Photonis MCP detectors to 300–1500 keV electrons and 500 keV photons (gamma rays) using a Van de Graff electron gun available at ONERA, Toulouse, France. The efficiency of the tested MCP for high-energy electrons is about 20–30% below 100 keV and is reduced to 10% for electron energies greater than 100 keV. The efficiency of the tested MCP for the gamma radiation of 500 keV energy is approximately 0.1%.

The Jupiter Icy moon Explorer (JUICE) is a long-life ESA mission to be working in extremely harsh space environment. The energetic neutral atoms imager (JENI), designed as a Time-of-Flight (TOF) spectrometer, contains microchannel plate (MCP) detectors to register start and stop secondary electrons produced by incident neutrals atoms. Due to rather severe mass and power constraints this spectrometer uses a single MCP assembly to detect both Start and Stop electrons, to define their detection time and then calculate an incident particle velocity. Thus one MCP is divided in several sectors. One of them is dedicated to detect Start electrons and another sector is detecting Stop electrons. Since the load of the Start sector can be higher than the load of the Stop sector by a factor of 10, it is important to know how does the MCP sectoral gain (Differential Gain) change during the MCP lifetime. Since the JUICE mission is a long-time mission it is important to be sure the MCP gain changes evenly along the active surface. To characterize the MCP overall gain uniformity we have combined the gain uniformity measurement and differential gain stability measurement into a single experiment of the MCP aging. A differential gain stability test has been performed on a representative MCP assembly using a uniform UV light source. The differential UV exposure has been achieved using an attenuation mask provided ~10% exposure of a majority of the MCP surface and full exposure of a small area. Differential gain versus the MCP bias voltage has been characterized every 0.5 C/cm2 of the charge extracted out of the MCP. We have shown the spatial gain variations and the differential degradation of the MCP sectors are acceptable for JENI experiment.

The microchannel plate (MCP) has been used for decades as a photon, electron and atoms detector in most of the space instruments dedicated for X-rays, energetic neutral atoms, and charged particle imaging. The deep-space missions, as near-future ESA Jupiter Icy moon Explorer (JUICE) mission, expect very low temperature conditions on the destination orbit. Since instruments are usually calibrated on the ground under the "room" temperature, it is very important to know the variation of the detectors properties with temperature. The resistance and the gain of the MCP detectors, dedicated for the JENI (PEP package) instrument onboard of JUICE, were measured as a function of temperature at INTRASPEC TECHNOLOGIES, Toulouse, France for the temperature range -50 to +50 degrees C and at the CALIPSO-3 facility of the Institut de Recherche en Astrophysique et Planetologie (IRAP), Toulouse, France for the temperature range -25 to +25 degrees C using samples from PHOTONIS France and PHOTONIS USA. It is also important to know how the resistance of the MCP detector behaves with temperature either to properly size the high-voltage source or, conversely, to choose a technology according to the size of the MCP detector and the maximum current that the high-voltage source can supply. Since the environment of Jupiter is very severe, the instruments will operate in the presence of high-energy particles that will induce background noise on the MCP detectors due to the shielding of the instruments against radiation. Therefore, the background noise in the Jovian environment represents a crucial issue for the MCP detectors whose gain can be degraded prematurely if too much charge is extracted from them due to the induced particles. Ours measurements show that the resistance of the MCP detector increases when the temperature decreases and is influenced by its self-heating, whereas the gain behavior depends on the technology of the MCPs. This is an important result which can be used to optimize the gain performance and the lifetime of the MCP detector. These experimental tests were funded by the French Space Agency CNES.

Bepi Colombo is a joint mission between ESA and JAXA that is scheduled for launch in 2014 and arrival at Mercury in 2020. A comprehensive set of particle sensors will be flown onboard the two probes that form Bepi Colombo. These sensors will allow a detailed investigation of the structure and dynamics of the charged particle environment at Mercury. Onboard the Mercury Magnetospheric Orbiter (MMO) the Mercury Electron Analyzers (MEA) sensors constitute the experiment dedicated to fast electron measurements between 3 and 25,500 eV. They consist of two top-hat electrostatic analyzers for angle-energy analysis followed by microchannel plate multipliers and collecting anodes. A notable and new feature of MEA is that the transmission factor of each analyzer can be varied in-flight electronically by a factor reaching up to 100, thus allowing to largely increasing the dynamical range of the experiment. This capability is of importance at Mercury where large changes of electron fluxes are expected from the solar wind to the various regions of the Mercury magnetosphere. While the first models are being delivered to JAXA, an engineering model has been tested and proven to fulfill the expectations about geometrical factor reduction and energy-angular transmission characteristics. Taking advantage of the spacecraft rotation with a 4s period, MEA will provide fast three-dimensional distribution functions of magnetospheric electrons, from energies of the solar wind and exospheric populations (a few eVs) up to the plasma sheet energy range (some tens of keV). The use of two sensors viewing perpendicular planes allows reaching a ¼ spin period time resolution, i.e., 1s, to obtain a full 3D distribution.