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Enceladus’s long-lived plume of ice grains and water vapor makes accessing oceanic material readily achievable from orbit (around Saturn or Enceladus) and from the moon’s surface. In preparation for the National Academies of Sciences, Engineering and Medicine 2023–2032 Planetary Science and Astrobiology Decadal Survey, we investigated four architectures capable of collecting and analyzing plume material from orbit and/or on the surface to address the most pressing questions at Enceladus: Is the subsurface ocean inhabited? Why, or why not? Trades specific to these four architectures were studied to allow an evaluation of the science return with respect to investment. The team found that Orbilander, a mission concept that would first orbit and then land on Enceladus, represented the best balance. Orbilander was thus studied at a higher fidelity, including a more detailed science operations plan during both orbital and landed phases, landing site characterization and selection analyses, and landing procedures. The Orbilander mission concept demonstrates that scientifically compelling but resource-conscious Flagship-class missions can be executed in the next decade to search for life at Enceladus.

surface of Mercury has been mapped in the 400–1145 nm wavelength range by the Mercury Atmospheric and Surface Composition Spectrometer (MASCS) instrument during orbital observations by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. Under the hypothesis that surface compositional information can be efficiently derived from spectral reflectance measurements with the use of machine learning techniques, we have conducted unsupervised hierarchical clustering analyses to identify and characterize spectral units from MASCS observations. We apply our analysis on the latest MESENGER data delivery to PDS including the new spectral photometric correction , finding result consistent with our previous analysis based on our custom photometric effect removal. The input is a global hyperspectral data cube image of normalized MASCS visible (VIS) detector spectra, from the first Earth year of the orbital mission. Data coverage varies from region to region, but global maps at 1 degree/pixel can be obtained with a high signal-to-noise ratio (SNR). The resultant hyperspectral map was then visually inspected to search for anomalies that originated mainly in regions of low coverage or from high levels of spectral variation within a single pixel. Our approach consist of several steps: 1. Data cleaning step: remove data artifact. 2. Independent Component Analysis (ICA): features compression and undelyng signal demixing. 3. Manifold learning : embedding of data in a low dimensional space via UMAP. 4. Hierarchical clustering : creation of spectrally similar partition and projection on the surface with comparison to existing human generated classifications. We found the existence of two large and spectrally distinct regions, which we call the polar spectral unit (PSU) and the equatorial spectral unit (ESU). The spatial extent of the polar unit in the northern hemisphere generally correlates well with that of the northern volcanic plains. Further analysis indicates the presence of smaller sub-units that lie near the boundaries of these large regions and may be transitional areas of intermediate spectral characters.

The Thalassa mission concept was developed in response to the 2019 NASA Planetary Mission Concept Studies call. Using a multi-platform mission architecture, Thalassa seeks to address a single science goal: to determine the extent to which water has played a role in the geological evolution of Venus.

Based on lunar observations, we calibrated the observation geometry of the MERTIS instrument on board the BepiColombo spacecraft.

In October 2020, BepiColombo performed a flyby maneuver at the Moon. The Mercury Radiometer and Thermal Infrared Spectrometer (MERTIS) was among the few instruments that could observe the Moon. We report on first preliminary results.

The lunar infrared spectra (7-14 um) acquired by MERTIS on 10th April 2020 exhibit an unexpected maximum at 9 um. We formulate a new hypothesis and perform radiative transfer modeling to explain the unusual shape of the spectra.

A primary science goal of astrobiology is to understand the biological potential of Solar System bodies. Looking beyond Earth, four planetary bodies, namely Mars, Europa, Titan and Enceladus, offer numerous opportunities to investigate the chemical evolution and origin of life. These bodies may have biochemistry similar to that of life on Earth (Davila and McKay, 2014; Taubner et al., 2018; Taubner et al., 2020). In recent years, exploration strategies have been developed to pursue astrobiological objectives for these targets. Two key scientific objectives of current and planned space missions to these bodies are 1) to investigate the abundance and distribution of the organic compounds and biomolecules, as well as environmental conditions (causing alteration, degradation and even complete destruction of these compounds such as irradiation, mineralogy etc.), as these are crucial in the search of biosignatures; and 2) to identify evidence of ancient biota and to determine whether indigenous organisms currently exist anywhere on the surface and subsurface of these planetary bodies.

We present results of spectral unmixing analyses of labradorite-enstatite-glass mineral mixtures using a non-linear unmixing model.

Two lunar soils: basalt and anorthosite, three glasses: synthetic glass, basalt glass, and obsidian measured in emissivity at 140°C. Soil with 20 µm glass on top was measured too, then heated to 900°C for four hours and then again measured in emissivity.

BepiColombo spacecraft is performing 9 flybys: among them, the Earth/Moon flyby on April 10, 2020, and the Venus flyby on October 15, 2020 (second Venus flyby around August 10, 2021). Among the few instruments that can operate is MERTIS.

The plume of Enceladus provides access to fresh material from a habitable, subsurface ocean. We summarize in this white paper the evidence for Enceladus’ ocean and its habitability, identify constraints and outstanding questions on the detectability of life within Enceladus, and recommend a return to Enceladus beginning in the coming decade.

MERTIS will observe Mercury's surface at 500 m scale and combines a spectrometer and a radiometer covering the 7-14 µm and 7-40 µm ranges. MERTIS observed the Moon in April 2020 and Venus in October 2020, and its archival data are stored in PDS4 format.

Using five band orbital emissivity measurements in the 1 micron region has tremendous potential to provide global maps of Venus surface rock types. Combining this with 480°C laboratory measurement will poise Venus science for a dramatic improvement in understanding of surface geology and the formation and internal processes of Earth’s twin planet.

Venus Corona and Tessera Explorer (VeCaTEx) would use an aerobot to descend repeatedly beneath the dense clouds for imaging targeted area of the surface in the near infrared to address six of the prime investigations prioritized by VEXAG. The technologies needed could be matured during the next decade.

In situ information on the surface composition of Venus is based on measurements of a small number of landing sites. In the laboratory, we measured the emissivity of a range of igneous rocks at temperatures up to 480°C. We show that high-temperature laboratory spectra of basalts are consistent with the only existing multispectral data from the surface of Venus obtained by the photometers on the Venera 9 and 10 landers. We derive the FeO abundances for these landing sites of 12.2 and 9.5 weight %, respectively. From orbit, Venus’ surface is only observable on the nightside through small spectral windows near 1 μm where the CO2 atmosphere is largely transparent. The new laboratory data show that different rock types can be distinguished using only a small set of spectral bands. Therefore, future orbital spectral observations can provide a much-needed global composition map.

The dual spacecraft mission BepiColombo is the first joint mission between the European Space Agency (ESA) and the Japanese Aerospace Exploration Agency (JAXA) to explore the planet Mercury. BepiColombo was launched from Kourou (French Guiana) on October 20th, 2018, in its packed configuration including two spacecraft, a transfer module, and a sunshield. BepiColombo cruise trajectory is a long journey into the inner heliosphere, and it includes one flyby of the Earth (in April 2020), two of Venus (in October 2020 and August 2021), and six of Mercury (starting from 2021), before orbit insertion in December 2025. A big part of the mission instruments will be fully operational during the mission cruise phase, allowing unprecedented investigation of the different environments that will encounter during the 7-years long cruise. The present paper reviews all the planetary flybys and some interesting cruise configurations. Additional scientific research that will emerge in the coming years is also discussed, including the instruments that can contribute. Open Access funding provided by Istituto Nazionale di Astrofisica within the CRUI-CARE Agreement. Peerreview

Understanding Venus will benefit from a dedicated effort through an international program of missions that are coordinated and offering opportunities for coooperation. The recent discovery of phosphene in the Venus clouds and possibility of life will increase the exploration missions and cooperation and coordination will be very benefical.

International audience; More than 85% of the 23 investigations developed by VEXAG are largely accomplished via a NF mission centered on a variable-altitude balloon (aerobot) supported by a science/comm orbiter. Circling Venus >15 times over ~90 days, the aerobot repeatedly visits 52-62 km alts as it semi-continuously samples a host of environmental & surface parameters.

Experimental facilities dedicated to recreating the conditions on the surface of Venus are critical for advancing scientific understanding of the planet and developing the technologies needed to continue Venus exploration. These facilities should be supported and enhanced in the next decade to maximize our efforts to understand this key planet.

Primary author: Suzanne Smrekar Jet Propulsion Laboratory/California Institute of Technology, Pasadena CA ; Co-authors: Jeff Andrews-Hanna (U.AZ), Doris Breuer (DLR Berlin), Paul Byrne (NCSU), Debra Buczkowski (JHU/APL), Bruce Campbell (Nat. Air Space Museum), A. Davaille (CNRS/U. Paris-Saclay), Darby Dyar (Mt. Holyoke/PSI), G. Di Achille (INAF/Astro Obs. Teramo), Caleb Fassett (Marshall), Martha Gilmore (Wesleyan), Robert Grimm (SWRI), Jorn Helbert (DLR Berlin), Scott Hensley (JPL), Robert Herrick (U. Alaska), Luciano Iess (U.Roma), Lauren Jozwiak (JHU/APL), Tiffany Katiaria (JPL), Marco Mastrogiuseppe (U. Roma), Erwan Mazarico (Goddard), Nils Mueller (DLR Berlin), Daniel Nunes (JPL), Joseph O'Rourke (ASU); Patrick McGovern (LPI), Maria Raguso (Caltech), Joann Stock (Caltech), Constantine Tsang (SwRI), Thomas Widemann (Obs. Paris), Jennifer Whitten (Tulane), Thomas Widemann (LESIA), Howard Zebker (Stanford)

Instrument description The VenSpec-U instrument is a dual channel UV spectral imager (low and high spectral resolution channels, “LR” and “HR” hereafter), part of the VenSpec spectrometer suite on board the proposed Venus orbiter EnVision. Each channel consists of an entrance baffle, an objective composed of two lenses and a stop diaphragm, and a spectrometer composed of a slit and a toroidal holographic grating. It also includes s shortpass filter to reject the wavelengths above the higher limit of both channel bands and a zero-order trap to avoid straylight due to internal reflexions of the grating zero-order. The optical layout is presented in Figure 1. Both LR and HR slits are parallel and the optical layout is such that both channels have the same instantaneous field of view (FoV), allowing simultaneous observations and calibrations. Each slit image is then spectrally dispersed by its respective toroidal holographic grating and is formed on a shared CMOS back-side illuminated detector. Figure 1: VenSpec-U optical layout overview, with the HR and LR channels respectively on the left and on the right. The narrow-slit axis of the detector contains the spectral information, whereas the long-slit axis contains the spatial information along the 22.5° FoV of each slit. The spectra of LR and HR channels are dispersed one above the other on the focal plane. The remaining spatial direction is provided through orbital scrolling (“pushbroom” strategy). Binning on the spatial axis is performed on the detector. The detector will be controlled such that the integration time and the binning scheme is adjusted independently (and simultaneously) for each channel giving high flexibility and providing parameters for the optimisation of each acquisition. Instrument Performance the HR channel (210-240 nm) at 0.2 nm spectral resolution and spatial sampling not coarser than 36 km (12 km target) should reach a SNR of at least 100; the LR channel (190-380 nm) at 2 nm spectral resolution and spatial sampling not coarser than 6 km (3 km target) should reach a SNR of at least 200. According to our forward model based on HST-STIS [Jessup et al., 2015] and SPICAV-UV heritage [Marcq et al., 2020], this shall be sufficient to measure the targeted species (SO, SO2, UV absorber) with a relative accuracy better than 25%. These measurements shall allow to characterize variability of Venus cloud top on temporal scales ranging from hours to years and spatial scales ranging from a few kilometers to planetary scale in relation to the climate and/or present day volcanic activity of Venus. Bibliography K. L. Jessup et al., Coordinated Hubble Space Telescope and Venus Express Observations of Venus’ upper cloud deck, Icarus 258, 2015 E. Marcq et al., Climatology of SO2 and UV absorber at Venus’ cloud top from SPICAV-UV nadir dataset, Icarus 335, 2020

The Io Volcano Observer (IVO) [1] is a NASA Discovery mission currently under Phase A study [2]. Its primary goal is a thorough investigation of Io (e.g., [3]), the innermost of Jupiter's Galilean moons and the most volcanically active body in the Solar system. The strategy consists of the observation of Io mainly during ten targeted flybys [4] between August 2033 and April 2037. At this time, IVO will orbit Jupiter on highly eccentric orbits with periods between 78 and 260 days, a minimum Jupiter altitude of ~340000 km, apoapsis distances between 10 and 23 million kilometers, and an orbit inclination of ~45°. Among the remote-sensing and field-and-particle instruments, there are also a narrow-angle camera (NAC; clear aperture of ~15 cm; pixel field-of-view of 10 µrad) and an infrared mapping instrument (TMAP). The irregular moons of Jupiter [5] are a group of Solar system objects which is poorly studied. With 71 currently known objects ranging in size from ~150 x 120 km (Himalia) down to ~2 km, they are the largest sub-group of Jovian moons with respect to quantity. Irregular moons are believed to be remnants from catastrophic collisions of progenitor objects suspected to have been trapped by Jupiter in the early history of the Solar system. Many details and characteristics, including their region of origin and their relationship to other small bodies, are not known [6]. The first irregular-moon inventory by a spacecraft orbiting the host planet was successfully performed within the Saturn system by the Cassini spacecraft [7] [8]. Especially in the second half of the mission, approximately one or two days per orbit were used to observe Saturn's irregular moons, resulting in more than 200 observations of these objects. Since Saturn's irregulars were between 4 and >30 million kilometers away from Cassini (except for the targeted Phoebe flyby in June 2004), the objects appear smaller than a pixel in the imaging data. From photometric time series observations, lightcurves were extracted. These lightcurves allowed determination of 24 previously unknown rotation periods and 13 pole solutions, shape models, and phase curves. No such inventory has been done so far at Jupiter, Uranus, or Neptune systems. Irregular moons are difficult to observe from Earth using small and mid-sized telescopes because of their small sizes (most diameters are below 10 km) and thus faint appearance (most are darker than 23rd magnitude). In addition, there is a significant straylight problem from bright Jupiter. Furthermore, since they are quite numerous, thorough inventories are not possible because there are not enough large telescopes available. With a spacecraft like Cassini or IVO orbiting close to these objects, the situation improves fundamentally. No large telescopes are needed anymore because the objects appear much brighter, and because the angular distances to the planet are large. In addition, the long orbits of IVO offer plenty of uninterrupted observation time over many hours and days. In addition, a large phase-angle range as well as out-of-orbit plane observations are possible, adding crucial information that is not possible to achieve from Earth. Similar to the campaign with Cassini at Saturn, the major scientific goal of IVO's observations of irregular moons is to determine fundamental physical properties such as rotation periods, pole directions, sizes, and brightnesses as a function of illumination conditions (phase curves), as well as to provide constraints on object shapes (convex-shape models). This campaign would address many of the fundamental research goals formulated for small Solar system bodies by NASA's Small Bodies Assessment Group [9] [10]. These goals include the role of the irregulars in Solar system formation and dynamical evolution; a more complete understanding of the census, architecture, physical properties (size, shape, mass, density, porosity, spin rate, etc.), surfaces, surface alteration processes, and nature of interiors, as well as relationships to other bodies, events, and processes. With IVO, fundamental remote-sensing data can be obtained to move closer to achieving these goals. Since IVO's orbits are very long, this mission provides an ideal platform for a detailed survey campaign of these intriguing bodies. Performing coordinated observations with other missions (like ESA's JUICE), or combining observations with laboratory measurements (as proposed in the IVO mission as well) will improve the overall value and interpretation of the collected data. Fig. 1: Range (red line) and phase angle (green) of Jupiter as seen from IVO during the orbit tour. Fig. 2: Range, phase angle, and apparent magnitude of Jovian irregular moon Sinope (J9; ø ~ 35 km) as seen from IVO. This plot illustrates the potential of IVO observations of irregular moons. Sinope is the irregular moons where IVO comes closest in the current orbit tour. On 27 Dec 2033, the minimum distance will be 690000 km. In the IVO-NAC, the size of Sinope will be ~6 pxl at this time. References: [1] https://ivo.lpl.arizona.edu/ [2] https://www.nasa.gov/press-release/nasa-selects-four-possible-missions-to-study-the-secrets-of-the-solar-system [3] McEwen, A.S., de Kleer, K., Park, R. (2019): Does Io Have a Magma Ocean? eos.org. https://eos.org/features/does-io-have-a-magma-ocean [4] https://youtu.be/7AO4CDwIXv0 [5] https://sites.google.com/carnegiescience.edu/sheppard/moons/jupitermoons [6] Nicholson, P.D., Ćuk, M., Sheppard, S.S., Nesvorný, D., Johnson, T.V. (2008): Irregular satellites of the giant planets. In: The Solar System Beyond Neptune (Barucci, M.A. et al., eds.), Space Science Series, The University of Arizona Press, 411-424. [7] Denk, T., Mottola, S., Tosi, F., Bottke, W.F., Hamilton, D.P. (2018): The Irregular Satellites of Saturn. In: Enceladus and the Icy Moons of Saturn (Schenk, P.M., Clark, R.N., Howett, C.J.A., Verbiscer, A.J., Waite, J.H., editors), Space Science Series, The University of Arizona Press, 409-434. doi:10.2458/azu_uapress_9780816537075-ch020. [8] Denk, T., Mottola, S. (2019): Studies of Irregular Satellites: I. Lightcurves and Rotation Periods of 25 Saturnian Moons from Cassini Observations. Icarus 322, 80-103. doi:10.1016/j.icarus.2018.12.040. [9] SBAG (2016): Goals and Objectives for the Exploration and Investigation of the Solar System’s Small Bodies. Version 1, 04 Mar 2016, 41 pp. https://www.lpi.usra.edu/sbag/goals/SBAG_GoalsDoc_ver.1.2.2016.pdf [10] SBAG (2020): Goals and Objectives for the Exploration and Investigation of the Solar System's Small Bodies. Version 2, 19 Feb 2020, 47 pp. https://www.lpi.usra.edu/sbag/goals/SBAG_Goals_Document_2020.pdf

ESA’s ExoMars program comprises two missions including the Trace Gas Orbiter (TGO), launched in 2016, and a rover and surface platform, to be launched in 2022. The main scientific objectives of the program are to investigate the Martian environment and climate and search for past or present signs of life. For this purpose, a suite of three infrared spectrometers for remote sensing (Atmospheric Chemistry Suite, ACS) is in use on TGO. One of these instruments is a Fourier transform spectrometer, TIRVIM (Thermal IR V-shape Interferometer Mounting in honor of Vassili Ivanovich Moroz), operating in nadir, limb or solar occultation mode between 1.7 and 17 μm. On ExoMars22’s surface platform the spectrometer FAST (Fourier for Atmospheric Species and Temperature) will study the atmosphere and surface at the landing site in the same wavelength range as TIRVIM on TGO. This paper presents the objectives of TIRVIM and FAST. It summarizes selected results of the determination of temperature profiles and dust content in the lower atmosphere of Mars based on radiative transfer modeling of TIRVIM data. Synergetic analyses of TIRVIM spectra and InSight (NASA) in situ measurements of temperature and pressure at InSight’s landing site in Elysium Planitia enable improvements of procedures to retrieve parameters from TIRVIM observations. First results on surface temperature obtained from these different data sets together with the measurements to be expected in the future from FAST offer a unique opportunity to compare in situ and IR remote sensing measurements.

Feldspars are major components of terrestrial planetary surfaces. For future space application and the setup of a comprehensive reference database, Na- and K-rich alkali feldspars, NaAlSi3O8 – KAlSi3O8, have been investigated by infrared reflectance spectroscopy. We related the feldspar spectra to the chemical composition and state of Al,Si order/disorder. The infrared measurements were analyzed with respect to band shifts and peak shapes using the autocorrelation function. Natural samples served as starting materials. Some samples were treated by the alkali exchange method to produce pure end-members, which were then heated to generate various states of Al,Si disorder. X-ray diffraction (XRD) methods served to determine the Al,Si distribution. Our autocorrelation allowed to differentiate between the compositional and the order/disorder influences seen in the spectra in the wavelength range between 7 μm up to 14 μm (1429 cm− 1 to 714 cm− 1). Space missions often analyze the surfaces of planetary bodies using remote sensing. Therefore, our results are essential to characterize and distinguish alkali feldspars on the surfaces of terrestrial planetary bodies like Mercury., Deutsches Zentrum für Luft- und Raumfahrt https://doi.org/10.13039/501100002946

Unravelling how long life can persist under extreme dryness and what kind of environmental extremes can be faced by dried microorganisms, is relevant to understand Mars habitability and to search for life on planets with transient liquid water availability. Since trehalose and sucrose stabilize dried anhydrobiotes, an in silico survey of the genome of the desert cyanobacterium Chroococcidiopsis sp. CCMEE 029 was performed to identify pathways for trehalose and sucrose biosynthesis. The expression of the identified genes was induced in response to desiccation and trehalose and sucrose accumulation was detected in dried cells. This adaptation strategy enabled viability and biomarker permanence under extreme dryness and Mars-like UV flux. Chroococcidiopsis survivors were scored in 7-year dried biofilms mixed with phyllosilicatic Mars regolith simulant and exposed to 5.5 x 103 kJ/m2 of a Mars-like UV flux. No survivors occurred after exposure to 5.5 x 105 kJ/m2, although in dead cells, photosynthetic pigments and nucleic acids, both DNA and RNA, were still detectable. This suggested that dried biofilms mixed with phyllosilicatic Martian regolith simulant are suitable candidates to identify biosignatures embedded in planetary analogue minerals as planned in the future BioSigN (BioSignatures and habitable Niches) space mission to be performed outside the International Space Station.

In this chapter, the key technologies and the instrumentation required for the subsurface exploration of ocean worlds are discussed. The focus is laid on Jupiter’s moon Europa and Saturn’s moon Enceladus because they have the highest potential for such missions in the near future. The exploration of their oceans requires landing on the surface, penetrating the thick ice shell with an ice-penetrating probe, and probably diving with an underwater vehicle through dozens of kilometers of water to the ocean floor, to have the chance to find life, if it exists. Technologically, such missions are extremely challenging. The required key technologies include power generation, communications, pressure resistance, radiation hardness, corrosion protection, navigation, miniaturization, autonomy, and sterilization and cleaning. Simpler mission concepts involve impactors and penetrators or – in the case of Enceladus – plume-fly-through missions.

Outer membrane vesicles (OMVs), produced by nonpathogenic Gram-negative bacteria, have potentially useful biotechnological applications in extraterrestrial extreme environments. However, their biological effects under the impact of various stressors have to be elucidated for safety reasons. In the spaceflight experiment, model biofilm kombucha microbial community (KMC) samples, in which Komagataeibacter intermedius was a dominant community-member, were exposed under simulated Martian factors (i.e., pressure, atmosphere, and UV-illumination) outside the International Space Station (ISS) for 1.5 years. In this study, we have determined that OMVs from post-flight K. intermedius displayed changes in membrane composition, depending on the location of the samples and some other factors. Membrane lipids such as sterols, fatty acids (FAs), and phospholipids (PLs) were modulated under the Mars-like stressors, and saturated FAs, as well as both short-chain saturated and trans FAs, appeared in the membranes of OMVs shed by both post-UV-illuminated and "dark" bacteria. The relative content of zwitterionic and anionic PLs changed, producing a change in surface properties of outer membranes, thereby resulting in a loss of interaction capability with polynucleotides. The changed composition of membranes promoted a bigger OMV size, which correlated with changes of OMV fitness. Biochemical characterization of the membrane-associated enzymes revealed an increase in their activity (DNAse, dehydrogenase) compared to wild type. Other functional membrane-associated capabilities of OMVs (e.g., proton accumulation, interaction with linear DNA, or synaptosomes) were also altered after exposure to the spaceflight stressors. Despite alterations in membranes, vesicles did not acquire endotoxicity, cytotoxicity, and neurotoxicity. Altogether, our results show that OMVs, originating from rationally selected nonpathogenic Gram-negative bacteria, can be considered as candidates in the design of postbiotics or edible mucosal vaccines for in situ production in extreme environment. Furthermore, these OMVs could also be used as promising delivery vectors for applications in Astromedicine.

For planetary sciences, the main archives to archived access to mission data are ESA's Planetary Science Archive (PSA) and the Planetary Data System (PSA) nodes in the USA. Along with recent and upcoming planetary missions the amount of different data (remote sensing/in-situ data, derived products) increases constantly and serves as basis for scientific research resulting in derived scientific data and information. Within missions to Mercury (BepiColombo), the Outer Solar System moons (JUICE), and asteroids (NASA`s DAWN), one way of scientific analysis, the systematic mapping of surfaces, has received new impulses, also in Europe. These systematic surface analyses are based on the numeric and visual comparison and combination of different remote sensing data sets, such as optical image data, spectral-/hyperspectral sensor data, radar images, and/or derived products like digital terrain models. The analyses mainly results in map figures, data, and profiles/diagrams, and serves for describing research investigations within scientific publications.

The Mercury Radiometer and Thermal Infrared Spectrometer (MERTIS) is part of the ESA BepiColombo Mercury Planetary Orbiter (MPO) payload and consists of a push-broom IR-spectrometer (-TIS) and a radiometer (-TIR) [1]. MERTIS-TIS and -TIR make use of the same optics, electronics, and inflight calibration components [2, 3]. MERTIS-TIS operates at wavelengths of 7-14 µm, has 78 spectral channels, and a spectral resolution of λ/∆λ=78-156. The radiometer operates between 7 and 40 µm with 2 spectral channels. Depending on surface characteristics, MERTIS spectral resolution is adapted to optimize the S/R ratio. Thus, the instrument is capable of resolving weak spectral bands with less than 1% contrast. During the long cruise to Mercury, and before its arrival on December 5th 2025, BepiColombo will perform 9 flybys: among them, the Earth/Moon flyby on April 10 th 2020. Due to the flight configuration, not all the instruments onboard BepiColombo are able to operate during cruise and flybys. Among the instruments that can operate is MERTIS. The MERTIS imaging spectrometer will provide the first hyperspectral observation of the Moon in the thermal infrared (TIR) wavelength range from space. At the Planetary Spectroscopy Laboratory (PSL) of DLR in Berlin, a spectral library for lunar analog rocks in the TIR spectral range, measured under simulated Moon surface conditions, has been built to help the interpretation of MERTIS’ Moon spectra.

IntroductionShock-induced changes in planetary materials related to impacts or planetary collisions are known to be capable of altering their optical properties. One such example is observed in ordinary chondrite meteorites. The highly shocked silicate-rich ordinary chondrite material is optically darkened and its typical S-complex-like asteroid spectrum is altered toward a darker, featureless spectrum resembling the C/X complex asteroids. Thus, one can hypothesize that a significant portion of the ordinary chondrite material may be hidden within the observed C/X asteroid population.The exact pressure-temperature conditions of the shock-induced darkening are, however, not well constrained and due to this gap in knowledge, it is not possible to correctly assess the significance of the shock darkening within the asteroid population. In order to address this shortcoming, we experimentally investigate the gradual changes in the chondrite material optical properties together with the associated mineral and textural features as a function of the shock pressure. For this purpose, we use a Chelyabinsk meteorite (LL5 chondrite), which is subjected to a spherical shock experiment. The spherical shock experiment geometry allows for a gradual increase in the shock pressure within a single spherically shaped sample from 15 GPa at its rim toward hundreds of gigapascals in the center.ResultsFour distinct zones were observed with an increasing shock load (Fig. 1). We number the zones in the direction of increasing shock from the outside toward the center as zones I–IV The optical changes in zone I are minimal up to ~50 GPa. In the region of ~50–60 GPa corresponding to zone II, shock darkening occurs due to the troilite melt infusion into silicates. This process abruptly ceases at pressures of ~60 GPa in zone III due to an onset of silicate melting and immiscibility of troilite and silicate melts. Silicate melt coats residual silicate grains and prevents troilite from further penetration into cracks. At pressures higher than ~150 GPa (zone IV), complete recrystallization occurs and is associated with a second-stage shock darkening due to fine troilite-metal eutectic grains.The order of the spectral curves in the UV-VIS-NIR (ultraviolet – visible – near-infrared) region follows the visual brightness in which zone I is the brightest, followed by zones III and II, and zone IV is the darkest one (Fig. 2). The MIR reflectance (Fig. 3) follows the same albedo order as UV-VIS-NIR up to the primary Christiansen feature at 8.7 µm. At higher wavelengths in the Si-O reststrahlen bands region, the reflectance order changes with zones II and III, which are brighter than zones I and IV. The comparison of the powdered sample spectra to the one obtained from the rough saw-cut surface reveals the following trends. The overall reflectance of the powdered sample is an order of magnitude lower compared to the rough surface one. The reststrahlen bands in both samples show similar positions at approximately 9.1, 9.5–9.6, 10.3, 10.8, 11.3, and 11.8–12 µm. They are dominated by olivine with possible presence of orthopyroxene. The amplitudes of the reststrahlen bands are higher in the rough surface sample. The transparency feature at 12.7 µm is only observed in the powdered sample. The primary Christiansen feature at 8.7 µm is more pronounced in the powdered sample, while the secondary one at 15.6 µm is of a low amplitude in both samples.ConclusionsThe important finding is the presence of the two distinct shock darkening mechanisms in ordinary chondrite material with characteristic material fabric and distinct pressure regions. These two regions are separated by a pressure interval where no darkening occurs. Thus, the volume of the darkened material produced during asteroid collisions may be somewhat lower than assumed from a continuous darkening process. While the darkening mainly affects the UV-VIS-NIR region and 1 and 2-µm silicate absorption bands, it does not significantly affect the silicate spectral features in the MIR region. These are more affected by material roughness. MIR observations have the potential to identify darkened ordinary chondrite material with an otherwise featureless UV-VIS-NIR spectrum.

MERTIS will observe Mercury's surface with IR grating spectrometer and a radiometer. PDS4 Data will be in FITS and ASCII, for machine and human interaction.

We present a spectral database for reflectance and emissivity of rocks for the interpretation of in situ/remote measurements for lunar and planetary missions.

The project aims to a prototypical system for structured storage and visualization of planetary data compiled and developed within planetary institutions.

We studied the effect of graphite on reflectance and emissivity spectra of pure minerals, chosen among a list of mercury analogues, when mixed with 5% graphite.

A primary objective of the TREX SSERVI team (trex.psi.edu) is to study dust in distributed laboratories and apply the knowledge gained to interpreting surface characteristics of the Moon, asteroids, martian moons, and other airless bodies to ultimately increase the safety of crewed missions to these surfaces. The focus of this abstract is spectroscopy of fine particulate (

BIOLEX is a concept designed for in situ science on the Moon or in its orbit. As heritage of the polar and space experiment BIOMEX (Biology and Mars Experiment) on the ISS it is a more developed concept. Measurement operations on an exposure platform as well as within a micro-greenhouse device are part of this concept. The goal is to investigate the use of lunar resources as well as to analyse the stability of biomolecules as potential biosignatures serving as reference for future space exploration missions to Mars and the icy ocean moons in the outer solar system. Astrobiological exploration of the solar system is a priority research area such as emphasized by the European Astrobiology Roadmap (AstRoMap). It is focusing on several research topics, such as "Habitability" and on "Biomarkers for the detection of life". Therefore, "space platforms and laboratories", such as the EXPOSE setup installed outside the ISS, are essential to gain more knowledge on space- and planetary environments, which might be an essential basis for improvement of the robotic and human interplanetary exploration (Moon, Mars, Encedalus, Titan and Europa). In reference to these exposure platforms a new generation of hardware is needed to be installed in the lunar orbit or directly on the Moon. The BIOLEX is representing by its LOGOS (Lunar Organisms, Geo-microbiology and Organics Space Experiment) cubes such a concept combining the life detection topics with topics relevant to autonomous life supporting systems. A combination of a sample exposure device and a microhabitat for plants and microorganisms could address a tremendous number of questions from astrobiology and life sciences. The main scientific objectives for the use of BIOLEX-LOGOS cubes are: (i) in situ measurements by spectroscopy methods (such as Raman, IR, UV/VISspectroscopy) for analysis of biosignatures and their stability what is relevant for support of future life detection missions on Mars and the icy moons in the outer solar system); (ii) in situ measurements of environmental conditions (radiation, pressure/vacuum, temperature, pH, humidity) in micro-modules or compartments in reference to planned micro-habitat experiments placed on the Moon or incorporated on an exposure facility in orbit; (iii) in situ measurements of microorganisms’ activity in micro-modules / compartments in reference to planned microhabitat experiments placed on the moon or incorporated in the exposure facility in orbit. In reference to these scientific ideas the Moon is an excellent platform to operate different space experiments which will be of relevance for astrobiology, life sciences and human space missions. BIOLEX tries to fulfil a large number of scientific investigations in reference to these disciplines. The lunar environment is much harsher compared to Mars; and tests on biomolecules in this environment could provide information on their stability and therefore on the value to be used as reference for future space missions to Mars or the icy ocean moons in the outer solar system. Resources of the Moon such as the regolith or the freely available radiation on the surface could be tested by using them in a micro-greenhouse. Within this greenhouse different filters could test the optimal spectra range of the radiation.

The imaging spectrometer MERTIS (Mercury Radiometer and Thermal Infrared Spectrometer) is part of the payload of ESA/JAXA’s BepiColombo mission, launched in 2018 [1,2]. The instrument consists of an IR-spectrometer and radiometer, which will observe the surface in the wavelength range of 7–14µm and 7–40μm, respectively. In preparation of the mission, we are investigating Mercury analog minerals at the IRIS (Infrared and Raman for Interplanetary Spectroscopy) laboratory of the Institut für Planetologie at the Westfälische Wilhelms-Universität Münster. We study typical rock-forming minerals, e.g., pyroxenes, olivines, and feldspars, as well as mineral mixtures.Here we present results of a deconvolution model used to quantify mineral specific abundances of mineral mixtures [4,5]. Planetary surfaces are composed of a variety of different minerals, therefore the obtained spectral data reflects a mixture of these minerals. In order to quantify the mineral abundances a non-linear unmixing model is necessary. Our model is based on the Hapke reflectance theory [6-8] and is applied to data obtained at the IRIS laboratory [9]. Results of olivine and pyroxene mixtures, as well as grain size mixtures, will be presented at the meeting.We used olivine (Fo91) from Dreiser Weiher, Germany, and pyroxene (En87) from Bamble, Norway and a range of mineral mixtures for IR measurements. Samples are sieved in grain size fractions of The pure pyroxene and olivine spectra clearly show characteristic Christiansen features and Reststrahlen bands for all applied geometries and increasing phase angles result in decreased intensities. The reflectance increases from pyroxene and pyroxene-rich mixtures to olivine and olivine-rich mixtures. Moreover, the olivine-rich mixtures exhibit more olivine reflectance features, compared to pyroxene-rich mixtures [11].Our studies of pyroxene grain size analysis focus on pyroxene mixtures of 50%fine/50%coarse and 30%fine/70%coarse material. Generally, the intensities increase with increasing grain sizes. The transparency feature is evident for small grain sizes and the 50%fine/50%coarse mixture.At IRIS laboratory, we will further investigate planetary analog material and their mineral mixtures applying various analytical techniques. With these data we are establishing a database that will enable the correct interpretation of MERTIS results. This work has been funded by DLR grant 50 QW 1701 in the framework of the BepiColombo mission. [1] Hiesinger H. et al. (2010) PSS58, 144-165. [2] Benkhoff J. et al. (2010) PSS58, 2-20. [3] Grumpe A. et al (2017) Icarus299, 1-14. [4] Rommel D. et al. (2017) Icarus284, 126-149. [5] Hapke B. (1981), JGR86(B4), 3039-3054. [6] Hapke B. (2002), Icarus157, 523-534. [7] Hapke B. (2012), 2ndCambr. Univ. Press., NY. [8] Bauch, K.E. et al. (2019) LPSC L, Abstract#2521. [9] Weber I. et al. (2019) LPSC L, Abstract#2326. [10] Weber, I. et al. (2020) LPSC LI, Abstract#1889.