Introduction

The two microphones onboard the Perseverance rover have now been operating for more than three years on the surface of Mars. They have provided the first sound recordings at the Martian surface and the most extensive acoustic dataset recorded on another planet.  The Martian microphones have recorded sound waves, and more generally signals, from a wide variety of sources. Given the novelty of this dataset, we felt the need for a catalogue of Martian sounds. This catalogue contains a description of every type of sound both from an individual and a statistical perspective. This allows us to highlight the particular characteristics of each of the sources that can be retrieved from recording their sounds, including possible variations over time for recurring recordings. Using this catalogue, we also discuss scientific applications for each of the sound sources, highlighting how useful microphone data are to survey the Martian environment. Finally, the catalogue serves as a starting point for newcomers by demonstrating how to use the acoustic data and explaining which features of the recordings are already well understood and identifying others that are still open to investigation.

The Martian microphones

Two microphones are operated onboard the Perseverance rover. The SuperCam Microphone [1], located on the mast unit, operates in two modes, the MIC only mode where up to 167 s of sound at 25 kHz can be recorded, and the MIC+LIBS mode that record the shots of the LIBS instrument. More than 24 hours of recording have been acquired in the first mode and more than 6000 LIBS sequences have been recorded in the second one. The EDLCam microphone [2], located on the side of the rover body, can record for longer period of times at 48 kHz. More than 12 hours of recordings, mainly rover sound, have been acquired.

Both microphones are subject to operational constraints that shape the resulting dataset.

Environment sound sources

While not being strictly speaking a sound, the signal coming from the interaction between the wind and the microphone is always present on the recording at different levels. This allows the microphone to act as a high frequency wind sensor [3]. The spectra of the wind recording contain information about atmospheric turbulence near the Martian surface [4], which can be studied at different times of year and day thanks to the regular coverage offered by the microphone’s dataset.

The microphone-derived wind signal has been used to resolve the properties of a dust devil that was recorded during a rare direct encounter with the rover. During this event [5] the sound of the dust grains carried by the vortex impacting on the rover were also recorded, allowing an estimation of their number density.

Artificial sound sources

Sound recording around every LIBS shot contains information about the sound wave travel times and energy that can be used to study the temperature fluctuation [6] and the atmospheric turbulence [7]. This is made possible through the speed of sound and the scintillation measurements at different times of year thanks to the almost daily coverage in LIBS sound recording. Other artificial sounds such as the Ingenuity helicopter [8] or the operation of different parts of the rover (driving, drilling, abrading, MOXIE compressor [9], pumping of the heat rejection system fluid) were also recorded. These data were used to study the acoustic properties of the Martian atmosphere [10] and to monitor the health of the rover systems.

Conclusion

After three years at the Martian surface, Perseverance has sent back to Earth a rich dataset of acoustic recordings that has already yielded numerous scientific results. As it continues its journey at the surface of Mars, we expect that the microphones will bring greater detail to the established results as well as leading to new discoveries. Moreover, lessons learned on this mission will be useful for future acoustic experiments on other planetary bodies [11, 12].

[1] Mimoun et al. (2023) Space Science Reviews, 219 [2] Maki et al. (2020) Space Science Reviews [3] Stott et al. (2023) JGR : Planets [4] Stott et al. (2024) 10th International Mars Conference [5] Murdoch et al. (2022) Nat. Commun. [6] Chide et al. (2022) GRL [7] Chide et al. (2024) J. Acoust. Soc. Am. 155, 420–435.  [8] Lorenz et al. (2023) Planetary and Space Sciences 230.  [9] Hecht et al. (2021) Space Science Review [10] Chide et al. (2023) Earth and Planetary Science Letters 615 [11] Barnes et al. (2021) The Planetary Science Journal,2,4 [12] Gillier et al. (2024) IPPW

How to cite: Gillier, M., Mimoun, D., Stott, A. E., Murdoch, N., Maurice, S., Chide, B., Jacob, X., Maki, J. N., Lorenz, R. D., and Hecht, M. H.: A catalogue of Martian sound, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-1183, https://doi.org/10.5194/epsc2024-1183, 2024.

Introduction

Mars’ feeble atmosphere and lack of a magnetosphere imply that the surface is exposed to ionizing radiation particles from solar winds as well as Galactic Cosmic Rays (GCRs). Thus, Martian radiation dose exposure is consequential for long-term human and robotic exploration. As such, it is critical to develop a rigorous and holistic understanding of the radiation surface environment using in-situ measurements acquired over large areas. Team Tumbleweed aims to revolutionise Mars exploration by offering a platform capable of navigating harsh terrain at lower costs and reduced mission risk. A swarm-based architecture, consisting of wind-driven Tumbleweed rovers, could open new doors for planetary science. Namely, a suite of miniaturized instruments hosted by this swarm would provide higher spatio-temporal resolutions for the characterisation of ionizing radiation and water equivalent hydrogen mapping at the near-surface level.

Problem Statement

Remote sensing measurements obtained from individual orbital instruments suffer from a lack of spatial and temporal resolution. For instance, the temporal resolution provided by orbiters is unable to satisfactorily capture time-dependent variations in quantities such as radiation exposure and particle spectra, resulting from episodic and cyclical events. 

Regarding spatial resolution, in the case of neutron spectrometers, this severely hampers the identification of mission-relevant water-ice deposits, as current spatial resolution provides data only at a resolution of 60 to 200 km (3600 km^2 per pixel, at best) from an altitude of 400 km (Malakhov et al., 2020).  As such, there are no high-resolution hydrogen or radiation exposure maps for Mars. Thus, ground truth measurements from the surface are indispensable. 

To date, investigations hosted on individual rovers have provided invaluable first measurements. However, forming a more complete understanding of Martian science necessitates investigations supported by infrastructures that can provide high spatio-temporal resolution and global scale coverage. In-situ measurements would not only provide higher spatial and temporal resolutions, but would also provide ground truth data for the corroboration of remote measurements made by orbiters. This calls for a diversification of exploration concepts and platforms to achieve maximum scientific return while reducing mission risk and cost.

Proposed Solution

Our proposed solution is a low-cost mission involving a swarm of wind-driven, box-kite-styled Tumbleweed rovers (Cohen et al., 2023).

To maximize the science return of each rover in the Tumbleweed swarm, we developed a methodology using scoring modifiers to assess instrument suitability based on mission goals. These were optimized against mass, volume and power constraints. This led to the following pre-selection of instruments:

• Hand-lens style imager
• Stereoscopic camera
• Radiation spectrometer/particle camera
• Neutron spectrometer
• Electric field sensor
• Wind sensor
• Dust sensor
• Pressure sensor
• Temperature sensor
• Soil pH sensor
• Relative humidity sensor
• Triaxial flux gate magnetometer

Exploring the synergies amongst our pre-selected list of instruments, we arrived at the opportunity to use radiation-focused instrumentation to simultaneously achieve high-resolution mapping of hydrogen in the near-surface environment.

Near-surface level water equivalent hydrogen (WEH) thermalizes neutrons when GCRs and Solar Particle Events finally interact with matter. Consequently, measuring the flux of epithermal neutrons is the best approach towards estimating hydrogen content in the Martian subsurface (Mitrofanov et al., 2022).

Hydrogen mapping at a high-spatial resolution is an essential factor in the definition of future human missions, and settlement, on Mars. As the atmosphere is composed of mostly carbon dioxide (95.32%), with WEH available a human mission would have access not only to water but to the products of the Sabatier reaction and subsequent water electrolysis (methane, water, hydrogen, oxygen), thus enabling ISRU and the production of Methalox, the rocket propellent that would be used for a safe return. 

Beyond hydrogen mapping, measuring cosmic rays may provide clues towards our comprehension of reality. Cosmic Ray Ensembles (CRE), for example, may exhibit large scale spatio-temporal correlations that would enable novel ways to study the properties of space-time, the nature of dark matter and the Lorentz invariance violation, empowering the scientific community in the research of these fundamental questions (Alvarez Castillo et al., 2023).

Additionally, our rovers would provide unprecedented data on Space Weather with the swarm architecture enabling multi-point measurements in the Martian planetary plasma system, illuminating the processes by which plasma interacts with the surface of celestial bodies lacking significant atmospheres. This would drive forward not only our understanding of atmospheric loss on Mars, but also deepen our understanding of its radiation environment and its dependence on the long-term solar cycle variation, altered during Coronal Mass Ejection events that shield the planet from GCRs (Holmstrom et al., 2024), for instance.

Combined hydrogen and radiation environment mapping are enabled by our current instrumentation pre-selection and magnified in scale by our mission architecture, potentially yielding a high-resolution spatio-temporal scouting of Mars. This, in turn, would allow a complete understanding of future possibilities for long-duration human missions to the Red Planet. Regions characterized by low radiation exposure and elevated concentration of sub-surface WEH would contribute towards identifying ideal candidate sites for future crewed missions.

Conclusion

The Tumbleweed Mission, featuring radiation and neutron spectrometers aboard a distributed network of spacecraft, holds the potential to revolutionize our understanding of Martian radiation environments and advance human exploration efforts by mapping hydrogen on the Red Planet. 

The Tumbleweed swarm would not only corroborate orbit-based measurements but also would provide invaluable information on the near-surface environment and their respective differences. Compared to orbital measurements, the Tumbleweed swarm can probe deeper into phenomena such as the effect of dust storms on ionizing radiation and the effect of diurnal and seasonal cycles. Furthermore, a Marswide network of radiation/cosmic-ray detectors would become a unique tool to study astrophysical phenomena, space weather and geophysics.

How to cite: Kingsnorth, J., Shanbhag, A., Balsemão, M., Bounova, G., Pikulić, L., Bonanno, L., Mikulskytė, O., and Rothenbuchner, J.: Scouting Ahead of Human Footsteps: The Role of the Tumbleweed Rover in Providing High-resolution Radiation and Water Mapping on Mars, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-790, https://doi.org/10.5194/epsc2024-790, 2024.

Introduction:  The JAXA Martian Moons Exploration (MMX) mission [1] will deploy the French-German IDEFIX rover (Fig. 1) to the surface of Phobos [2]. The IDEFIX rover will attempt wheeled-locomotion on a low-gravity surface for the first time thus providing a unique opportunity to study the surface properties of Phobos and the behaviour of regolith on small-bodies.

Figure 1 (left) The MMX IDEFIX rover (image credit: JAXA). (right) A WheelCam (image credit: CNES)

The WheelCams:  The IDEFIX rover includes two WheelCams, placed on the underside of the rover and each aimed at a different rover wheel [3]. The WheelCam image sensors are panchromatic and consist of a 2048 by 2048 array. The optics provide a field of view of 32.5° and a pixel resolution of approximately 100 μm at the centre of the image. The WheelCams are also equipped with LEDs to illuminate the scene; white LEDs to be used while driving, and three colour LEDs (590, 720 and 880 nm) to allow for multispectral imaging. The WheelCams can be operated in both an imaging and a movie mode. Typical movie frame rates are expected to be 1 image per mm moved for the front WheelCam, 1 image per cm moved for the rear WheelCam (the anticipated rover speed is ~0.1-4 mm/s).

Science Objectives of the WheelCams: The WheelCam images will be used to characterize the general grain properties of the regolith (size distribution, morphological parameters [3]), within the limits of the resolution. The WheelCam images will also be used to determine the adhesive properties of regolith particles stuck to the rover wheels and the depth of the wheel sinkage, which is closely linked to the load bearing strength [4] and friction angle of the regolith [5].  The linear and angular velocities of the wheel will be calculated from the WheelCam images in order to provide measurements of the traction and slippage of the wheel. In addition to providing important information about the performance of the locomotion, this also provides the shearing characteristics of the regolith [6,7]. Topographical reconstruction of the rover tracks, talus and tailings behind the wheels [8] will provide additional constraints on the physical properties of the regolith.  Finally, using the coloured LEDs it will be possible to study the mineralogical composition of the regolith from reflectance and albedo measurements, and to asses space weathering by comparing inside and outside of the rover tracks.

Preparing for the WheelCam analyses: In anticipation of the MMX mission, we have developed the MMX WheelCam testbed (Fig. 2, [9]) that recreates the scene that the WheelCams will observe during the mission (Fig. 3). The main objective of the testbed is to develop the image processing tools for the WheelCams. The testbed is instrumented with multiple sensors allowing measurements to be made of the sinkage of the wheel into the soil, and the slippage (essentially the loss of traction) of the wheel. The testbed also includes the MMX rover wheel, camera baffles, the LEDs and blackout panels to perform trials in representative lighting conditions. 

Figure 2. Two different views of the MMX WheelCam testbed at ISAE-SUPAERO.

Figure 3. WheelCam approximate field of views, as generated by the WheelCam testbed. (left) Front WheelCam perspective. (right) Rear WheelCam perspective.

We also perform Discrete Element Method simulations [10] in order to understand the influence of the low gravity environment on sinking and driving behaviour (Fig. 4; [11, 12]]. This is essential to ensure an accurate determination of the regolith properties from the wheel – surface interactions.

Figure 4. Snapshot from a rolling simulation where gravity is 0.006 m/s² and the rotational velocity is 0.65 rad/s [11,12].

Conclusions: This presentation will discuss the expected science return from the MMX IDEFIX rover WheelCams and provide a status of the preparatory activities and image processing pipelines under development.

Acknowledgments: We acknowledge CNES funding.

References: [1] Kuramoto, K. et al. EPS (2022), [2] Michel et al., EPS (2022), [3] Robin, C. et al., Nat. Comm. 2024, [4] Bigot, Lombardo et al. [5] Sullivan et al., JGR-Planets (2011), [6] Maimone, M. et al. J. Field Robotics (2007), [7] Reina, G. et al. IEEE/ASME Trans. On Mechatronics (2006), [8] Amsili, A. et al. EPSC 2024, [9] Passoni, L. et al., LPSC (2021), [10] Sunday, C. et al., MNRAS (2020), [11] Sunday, C., et al. EPSC (2022), [12] Sunday, C. PhD Thesis, ISAE-SUPAERO (2022).

How to cite: Murdoch, N., Sunday, C., Amsili, A., Tardivel, S., Robin, C., Vivet, D., Delton, P., Smith, J., Tur-Garcia, T., LaLucaa, V., Theret, N., Bertrand, J., Baroukh, J., Vernazza, P., Groussin, O., Jorda, L., Biele, J., Miyamoto, H., Ulamec, S., and Michel, P. and the MMX Rover Locomotion Team: The science goals of the IDEFIX rover WheelCams, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-1185, https://doi.org/10.5194/epsc2024-1185, 2024.

Multi-spacecraft missions after 2000 (Cluster II, THEMIS, Van Allen Probes, and MMS) have revolutionized our understanding of the causes, patterns and variability of a wide array of plasma phenomena in the terrestrial magnetospheric environment. ESCAPADE is a twin-spacecraft Mars mission concept that will similarly revolutionize our understanding of how solar wind momentum and energy flow throughout Mars’ magnetosphere to drive ion and sputtering escape, two processes that have helped shape Mars’ climate evolution over solar system history.

ESCAPADE will measure magnetic field strength and topology, ion plasma distributions as well as suprathermal electron flows and thermal electron and ion densities, from precessing elliptical 150 x ~8500 km orbits. ESCAPADE are small spacecraft (<200 kg dry mass) built by Rocket Lab USA, following ballistic Hohmann transfers to Mars. Our strategically-designed 1-year, 2-part scientific campaign of temporally and spatially-separated multipoint measurements in different regions of Mars’ diverse plasma environment, will allow us to untangle spatial from temporal variability and unravel the cause-and-effect of solar wind control of ion and sputtering escape for the first time.

ESCAPADE is a Category 3 Class D Tailored small satellite mission selected under the SIMPLEX-2 program and funded by NASA’s Heliophysics division, with a PI-managed cost cap of <$60 million. UC Berkeley Space Sciences Laboratory provides project management, systems engineering, mission assurance, deployable booms, ion and electron electrostatic analyzers, and mission and science operations. NASA Goddard provides magnetometers. Embry Riddle Aeronautical University provides Langmuir probes. Advanced Space provides mission design. Designing, developing, and operating two spacecraft at Mars for this budget necessarily entails a combination of high heritage instrumentation, streamlined processes, and a higher risk tolerance than is common for many scientific missions. ESCAPADE is due to launch on Blue Origin’s New Glenn launch vehicle in late 2024. This presentation will focus on science topics, mission data products, lessons learned by NASA and the ESCAPADE team, and development/launch updates.

How to cite: Xu, S., Lillis, R., Curry, S., Hara, T., Curtis, D., Taylor, E., and Courtade, S. and the ESCAPADE Team: ESCAPADE Update: unraveling cause and effect in Mars’ hybrid magnetosphere, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-133, https://doi.org/10.5194/epsc2024-133, 2024.

Introduction: Quantifying and mapping the precise amount of water ice in the subsurface of the Moon has proven challenging using only remote sensing data. However, this knowledge is crucial for planning long-term exploration missions that rely on the utilization of potential water reserves. Higher-resolution data and ground truth can be obtained by in situ measurements. Rover missions, such as NASA’s VIPER [1], promise to be highly valuable assets for lunar exploration as their mobility allows to analyse the lateral distribution of volatiles at much higher resolution than presently possible. Additionally, ESA’s upcoming PROSPECT mission [2] on a stationary lander will analyse the vertical distribution of water up to 1 m depth.

To somewhat remedy mass constraints and life-time limitations while still enabling scientific measurements, electric permittivity sensors can be utilized: Permittivity sensors measure the electric permittivity (and conductivity) in a low-frequency band, and are lightweight, have low impact on technical system budgets, and can acquire measurements quickly. Thereby, the soil’s porosity and water ice content can be deduced. As a drawback, the measurement depth of these sensors is limited to a few centimetres of measuring depth, on the same order of magnitude as the electrode size. Missions such as Cassini-Huygens [3] and Rosetta [4] have successfully demonstrated the concept and PROSPECT will feature a permittivity sensor integrated into its drill to characterize the vertical distribution of the lunar sub-surface at its landing position [2].

To combine the strengths of both rover mobility and permittivity sensor characteristics, small permittivity sensors can be attached to various surfaces, including rover wheels. At TUM, we currently develop such instrument arrangements, called patch electrodes, which will be used to identify and map the lateral abundance and state of lunar water ice at the lunar poles.

Background: Electrical permittivity is a measure of the electric polarizability of a dielectric and thus describes its ability to store energy in an electric field. Any mixture of materials between two electrodes and their respective relative permittivity influences the system’s electric capacitance. In the context of planetary exploration, this phenomenon can be exploited as the relative (static) permittivity of vacuum (=1), dry regolith (~5–8), and water ice (~80–100) differ significantly in both magnitude and behavior in the frequency domain over temperature [6]. Here, especially low temperatures are of interest [7].

Measuring the capacitance of a calibrated system thus allows for the deduction of the material’s bulk effective electric permittivity. The composition is subsequently calculated using simulations of the electric field’s geometry and mixing rules linking the effective permittivity to the volume shares and individual relative permittivity, for example Looyenga’s rule [8]. Figure 1 shows the expected effective relative static permittivity at a temperature of -20 °C for the three-component mixture of water ice, regolith, and vacuum and Looyenga’s mixing law. Under the assumption of known bulk density, the mass of volatiles in the sample can be determined by regression of the differences between multiple frequencies.

Experimental Setup: For the investigations under cryogenic conditions, a pulse tube cooled facility was used. It enables cooling a small sample (~10 cm³) to temperatures below -150 °C.

Figure 1: Expected effective relative permittivity for the investigated mixture. Stars indicate the investigated mixtures. Adapted from [9].

Possible compositions of samples are indicated in Figure 1 with star markers. White lines depict two different regolith volume shares and two different ice-to-vacuum ratios. The values for investigated regolith samples are selected to represent loosely poured regolith and compacted regolith, while binary water/air mixtures represent loose and compacted snow. Additionally, calibration without the container was performed before and after the campaign to characterize the instrument background/noise.

Sample temperatures ranged from -150 °C to 0 °C and were measured on the sample container and on the electrode using thin Type-K thermocouples. Multiple repetitions were performed for all setups. The measurements were taken with a commercial microcontroller (Teensy 4.1) on a custom front-end electronics board and processed using Discrete Fourier Transformation as described in [9].

Figure 2: Capacitances derived from measurements with the patch permittivity sensor for (A) pure water, (B) JSC-1A regolith, (C) air and (D) a mixture of JSC-1A with 10 % water by weight.

Preliminary Results: Figure 2 shows the bulk capacitance over frequency derived from Fourier analysis evaluated from measurements with the setup for temperatures between -40 °C to 0 °C in approximately 10 °C intervals. The samples were distilled water, dried JSC-1A (moisture content < 0.1 %), air, and a mixture of dry simulant with 10 % by weight of distilled water. The base excitation frequency of 6.25 Hz and the 20 kHz sampling frequency were chosen based on experience from previous studies.

The capacitances for JSC-1A and air follow the expected trend of an approximately constant relative permittivity over frequency and show a good signal-to-noise ratio (> 10, not shown) up to around 500 kHz. The mixture exhibits a capacitance ranging between its individual constituents, which qualitatively matches the expected mixing law. The magnitude and frequency behaviour of the measurements amongst each other shows the technique’s robustness and repeatability and are similar to published data [5,7]. The capacitancesre also in the expected range based on numerical simulations (pF).

Outlook: Further improvements both to the instrument as well as to the experimental setup are foreseen in the near future. The signal-to-noise ratio can be increased at higher frequencies with a software-based increase in base excitation frequency. A shift to lower frequencies may yield a better resolution at the spectrums lower end. Other regolith simulants (e.g. NU-LHT-2M or EAC-1) will also be investigated to gain confidence in the mixing laws. The results from this study will directly feed into the investigation of the sensor’s sensitivity, accuracy, and detection limits, as well as its applicability for further exploration missions.

References: [1] Colaprete et al. (2021) NESF & ELS 2021 [2]  Trautner R. et al (2024), Front. Space Tech. [3] Fulchignoni, M. et al. (2002) Space Sci. Rev. [4] Seidensticker, K. J. et al. (2007) Space Sci. Rev. [5] Nurge, M. A. (2012) Planet. Space Sci. [6] Sihvola, A. (2000) Subsurface Sensing Tech. and Appl. [7] Trautner R. et al. (2021) Meas. Sci. Technol [8] Looyenga (1965) Physica [9] Gscheidle C. et al (2024), Front. Space Tech.

How to cite: Gscheidle, C. and Reiss, P.: Investigation of Hydrated Regolith Simulant with Patch Permittivity Sensors for Planetary Exploration under Cryogenic Conditions, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-559, https://doi.org/10.5194/epsc2024-559, 2024.

Introduction:  In December 2020, China’s Chang’E-5 (CE-5) mission successfully landed in the northeastern part of Oceanus Procellarum on the Moon and achieved its goal of collecting lunar surface samples[1]. Chang’E-6 (CE-6) is China’s second lunar sample return mission following the CE-5 mission, and were launched on 3^rd May 2024 . The CE-6 landing zone has been selected to lie within the lunar farside South Pole–Aitken (SPA) basin in the southern part of the Apollo basin[2]. Both CE-5 and CE-6 missions are equipped with the Lunar Mineralogical Spectrometer (LMS) to conduct surface spectral scanning to obtain the mineralogical infromation of the sampling area. The LMS can acquire hyperspectral data from 480 nm to 3200 nm[3]. Due to in-orbit working time and condition limitations, LMS could not complete whole sampling area scanning using hyperspectral detection mode and has to adopt multispectral detection mode. In this study, we mainly introduced the design of band selection for the LMS multispectral detection mode.

Designed LMS multi-bands for CE-5 mission:  Remote sensing data reveals that the spectra of the CE-5 landing area exhibit longer-wavelengths ~1 μm and 2 μm absorptions, indicating that the CE-5 mare basalts are primarily composed of high-Ca pyroxene (HCP). Spectra of CE-5 landing area also show a much weaker 2 μm absorption relative to their 1 μm absorption, resembling the spectral characteristics of olivine[5]. In addition, CE-5 landing area contains a large amount of ejected materials from surrounding regions, including basaltic materials dominated by low-Ca pyroxene (LCP) from western old IM basaltic regions and materials dominated by plagioclase from the eastern highlands. Products associated with volcanic activity such as volcanic glass and ilmenite are also likely to contribute to the material in CE-5 landing area. Considering the spectral features of these mineral/glass and taking into account wavelength positions that can be used to estimate Fe, Ti and maturity as well as OH^-/H₂O, we finally selected 20 bands combination for CE-5 LMS (Table 1).

Optimization of multi-bands for CE-6 mission: The pyroxene composition of CE-6 landing area has changed significantly, ranging from Mg-rich LCP to Fe, Ca-rich HCP[2]. Spectral interpretation of pyroxene compositions of CE-6 landing area will greatly influence the analysis of the origin of the returned samples (mantle or lower crust). Therefore, for CE-6 mission, we increased the number of the selected bands around ~1 μm and 2 μm absorption to more accurately dipict the variation of absorption center of lunar soils resulting from the changing composition of pyroxene. Besides, to better characterize OH^-/H₂O absorption, we optimized the positions and increased the number of bands for 2200 nm-3200 nm regions (Table 1).

 Evaluation on displaying spectral features:

In general, the designed multi-bands can well display the hyperspectral features (measured by RELAB) of mineral/glass separated from lunar soils. LCP exhibits a shorter-wavelength absorption ~2000 nm, consistent with its hyperspectral data. HCP shows a flattening between ~2000 nm and ~2200 nm, indicating that its absorption center should be located between these two bands. The multispectral data allows for the effective display of olivine’s broader 1 μm absorption, and the hyperspectral features of the three types of lunar volcanic glasses are also well reproduced, particularly the longward 1 μm and shortward 2 μm wide absorptions. Compared to the multi-bands spectra of CE-5, the designed bands combination for CE-6 seems to be more efficient in reflecting the absorptions around ~2 μm and ~2.8 μm because of the optimization and increased number of bands selected for these two spectral regions.

References: [1] Li C. et al. (2022) NSR, 9, 2, nwab188. [2] Zeng X. et al. (2023) Nature Astronomy, 7, 1188-1197. [3] He Z. (2019) J. Appl. Remote Sens, 13(2). [4] Liu D. et al. (2002) Nature Communictions,13, 5965. [5] Staid M. I. et al. (2011) J. Geophys. Res. Planets, 116, E6.

Figure 1. Comparison between hyperspectral and multispectral data of minerals and glasses composing lunar soils. The multispectra were obtained by re-sampling the hyperspectra according to the spectral response function of CE-5 LMS multispectral detection mode.

Figure 2. Comparison between hyperspectral and multispectral data of minerals and glasses composing lunar soils. The multispectra were obtained by re-sampling the hyperspectra according to the spectral response function of CE-6 LMS multispectral detection mode.

Table 1  Designed LMS multi-bands

How to cite: Liu, D., Liu, B., Liu, J., Zhang, H., Su, Y., Zhu, X., and Li, C.: Bands Selection for Multispectral Detection Mode of Lunar Mineralogical Spectrometer of China’s Chang’E-5 and Chang’E-6 Missions, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-349, https://doi.org/10.5194/epsc2024-349, 2024.

The space environment is known to be populated by highly energetic particles that may be hazardous for the health of missions and impact planetary environments. The effects of these particles are commonly known as Space Weather. Monitoring interplanetary Space Weather in the Solar System is currently a challenging but essential activity that requires a good knowledge of the Sun and solar wind conditions, the local space environments (including solar wind-magnetosphere-ionosphere coupling), and the interaction of each spacecraft with its local environment. Consequently, understanding the chain of processes that control Space Weather at any planet or spacecraft on various time scales is important to accurately forecast and prevent hazardous conditions for a mission, and ultimately humans, throughout the Solar System.

These energetic particles originate from three main sources: (1) Galactic Cosmic Rays (GCRs), a low flux of protons (90%), heavy ions, and to some extent electrons, with energies up to 10E21 eV, arriving from outside of the Solar System; (2) Solar Energetic Particles (SEPs), sporadic and unpredictable bursts of electrons, protons, and heavy ions, travelling much faster than the space plasma, accelerated in Solar Flares and Coronal Mass Ejections; and (3) planetary trapped particles, a dynamic population of protons and electrons trapped around planetary magnetospheres first discovered at Earth by Van Allen. Solar activity is responsible for transient and long-term variation of the radiation environment. These three components of radiation in space combine into a hazardous environment for both manned and unmanned missions and are responsible for several processes in planetary bodies. Therefore, it is important to monitor and comprehend the dynamics of energetic particles in space.

BepiColombo and JUICE are two planetary missions from the European Space Agency that are currently travelling to their final destinations, i.e., Mercury and the Jovian system, respectively. Both of them have very long cruises within the Solar System. For BepiColombo, the journey is of 7 years (2018-2025) and for JUICE of 8 years (2023-2031). These long trips provide not only exceptional measurements for cross-calibration of instrumentation, but also for unique science opportunities including  collaborations with other solar missions, such as Parker Solar Probe and Solar Orbiter that are characterising the plasma environment within the Solar System. Additionally, JUICE and BepiColombo can also act as upstream solar wind monitors for other planets such as Venus,  Earth, Mars and Jupiter.

BepiColombo has a large suite of instruments dedicated to plasma and solar physics, most of them operating on regular basis during the cruise phase, such as the Solar Intensity X-Ray and Particle Spectrometer (SIXS), the BepiColombo Environmental Radiation Monitor (BERM), the Solar Particle Monitor (SPM), and the BepiColombo Planetary Magnetometer (MPO-MAG). Some instruments are operated on specific solar wind campaigns. In the case of JUICE, only the RADiation hard Electron Monitor (RADEM) is in continuous operation, the other instruments operate twice per year for a health check, during planetary swingbys, and potentially for longer periods in the second part of the cruise, once JUICE is further away from the Sun, and closer to its final destination.

In this work, we report on the solar energetic particle observations detected by both missions and the interplanetary magnetic fields (for the case of BepiColombo only), and how this unique opportunity for cruise observations is significantly helping the planetary and heliophysics communities to characterise Space Weather in the inner Solar System.

How to cite: Sanchez-Cano, B., Pinto, M., Witasse, O., Gonçalves, P., Hajdas, W., Galli, A., Santos, F., Gomes, A., Bunce, E., Rodríguez-García, L., Vainio, R., Murakami, G., Lehtolainen, A., Kilpua, E., Heyner, D., Oleynik, P., Grande, M., and Benkhoff, J.: Space Weather monitoring with BepiColombo and JUICE during their cruise phases, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-549, https://doi.org/10.5194/epsc2024-549, 2024.

The National Oceanic and Atmospheric Administration (NOAA) Space Weather Follow-On (SWFO) program includes a suite of in situ plasma instrumentation on the SWFO-L1 spacecraft along with compact coronagraphs (CCOR) on both SWFO-L1 and the GOES-U geostationary weather satellite. GOES-U is currently slated to launch in June 2024 and SWFO-L1 is slated to launch in April 2025. Here we provide an overview of the spacecraft and missions along with their instrumentation and products. The GOES-U CCOR-1 will be the first coronagraph flown for operational space weather monitoring. The SWFO-L1 in situ instruments include the Solar Wind Plasma Sensor (SWiPS), SupraThermal Ion Sensor (STIS), and a pair of fluxgate magnetometers (MAG). The in situ measurements for the plasma and interplanetary magnetic field (IMF) will be critical for driving NOAA’s magnetospheric and ionospheric models in real time. The suprathermal ion and electron measurements will be useful for early forecasts of arrival of geoeffective structures such as CMEs and interplanetary shocks. NOAA’s National Environmental Satellite, Data, and Information Service (NESDIS) will provide tracking and control along with data acquisition for the observations. The Space Weather Prediction Center (SWPC) will perform the real-time processing, product generation, and dissemination. The National Centers for Environmental Information (NCEI), part of NESDIS, will curate the data products for non-real-time (retrospective) users to browse and access via a comprehensive API and the upcoming Space Weather Portal. The SWFO Program will complement existing and planned observations from other satellites currently in NOAA’s satellite fleet along with satellites of partner domestic and international partner organizations.

How to cite: M Hill, S., Vassiliadis, D., Redmon, R., and Johnson, J.: NOAA’s Space Weather Follow-On (SWFO) Program, Europlanet Science Congress 2024, Berlin, Germany, 8–13 Sep 2024, EPSC2024-552, https://doi.org/10.5194/epsc2024-552, 2024.