The BepiColombo Mercury Imaging X-Ray Spectrometer: Science Goals, Instrument Performance and Operations

Abstract

The Mercury Imaging X-ray Spectrometer is a highly novel instrument that is designed to map Mercury’s elemental composition from orbit at two angular resolutions. By observing the fluorescence X-rays generated when solar-coronal X-rays and charged particles interact with the surface regolith, MIXS will be able to measure the atomic composition of the upper ∼10-20 μm of Mercury’s surface on the day-side. Through precipitating particles on the night-side, MIXS will also determine the dynamic interaction of the planet’s surface with the surrounding space environment. MIXS is composed of two complementary elements: MIXS-C is a collimated instrument which will achieve global coverage at a similar spatial resolution to that achieved (in the northern hemisphere only – i.e. ∼ 50 – 100 km) by MESSENGER; MIXS-T is the first ever X-ray telescope to be sent to another planet and will, during periods of high solar activity (or intense precipitation of charged particles), reveal the X-ray flux from Mercury at better than 10 km resolution. The design, performance, scientific goals and operations plans of the instrument are discussed, including the initial results from commissioning in space.

The Distribution of Peak‐Ring Basins on Mercury and Their Correlation With the High‐Mg/Si Terrane

“…To complete the analysis reported here, additional data need to be acquired to ascertain whether the statistical correlations can really be used to inform the origin of the HMT. The key data set to enable this work will come from MIXS once BepiColombo enters its science phase (Bunce et al., 2020). MIXS‐C will give more sensitive abundances at resolutions comparable to the best achieved by MESSENGER during its main science mission, MIXS‐T will provide imaging resolutions which will enable analysis of large crater features in regions illuminated by bright solar flares.…”

“…Among the 16 instruments shared across two spacecraft is the Mercury Imaging X‐ray Spectrometer (MIXS) on board the Mercury Planetary Orbiter (MPO). The MIXS instrument represents the first time a true‐imaging X‐ray spectrometer has been sent to another planet and it is expected to offer unprecedented insights into the surface elemental composition of Mercury (Bunce et al., 2020; Fraser et al., 2010). This instrument will follow on from the successful MErcury Surface, Space ENvironment, Geochemistry and Ranging (MESSENGER) mission (Solomon & Anderson, 2018) which has posed a number of questions of great scientific importance for follow up by BepiColombo.…”

The lifecycle of hollows on Mercury: An evaluation of candidate volatile phases and a novel model of formation

“…Additionally, the SIMBIO-SYS suite will have a moderate-resolution visible and nearinfrared hyperspectral imager (VIHI) with a spectral range of 400 -2000 nm, and with a spectral resolution of 6.25 nm/pixel. Hyperspectral images of hollow rims and floors could confirm the presence of sulfides within hollows (Helbert et al, 2013;Thomas et al, 2016;Lucchetti et al, 2018;Pajola et al, 2021) and the Mercury Imaging X-Ray Spectrometer (MIXS) will map S abundance across the planet (Bunce et al, 2020). Lastly, if the pore spaces of some sections of hollow floors and rims are mineralized, these units may have a higher thermal inertia than surrounding materials, which could be measured with the MERTIS instrument on BepiColombo (Hiesinger et al, 2020).…”

DEPFET Active Pixel Sensors

“…A further mitigation is the choice of a low operating temperature. The novel DEPFET detector concept was for the first time used in space for the Mercury Imaging X-ray Spectrometer (MIXS) on BepiColombo, a satellite for the exploration of planet Mercury [4] realised as joint mission of ESA and JAXA. The purpose of the MIXS instrument is the analysis of the elemental composition of the planet's surface by imaging X-ray spectroscopy of the fluorescence lines [16].…”