Poster presentations and abstracts

How to cite: Taheran, M., Duffard, R., Maier, P., Colin, A., Pahler, A., Bougueroua, S., Conti, L., Mueller, T., Lockowandt, C., Ortiz, J. L., Ångerman, M., Hanke, L., Janson, O., and Stelzer, B.: The STUDIO UV astronomy mission: a step towards a european ballon observatory, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-429, https://doi.org/10.5194/epsc2020-429, 2020.

How to cite: Phillips, C., Howell, S., Pappalardo, R., Senske, D., Korth, H., Kampmeier, J., Craft, K., Klima, R., and Leonard, E. and the Europa Clipper Science Team: Europa Clipper: Mission Status and Update, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-498, https://doi.org/10.5194/epsc2020-498, 2020.

Introduction

Planetary Radio Interferometry and Doppler Experiment (PRIDE) will exploit the signal recording and processing technology developed originally for Very Long Baseline interferometric (VLBI). The essence of PRIDE is in observing the spacecraft radio signal with a network of Earth-based radio telescopes. The PRIDE technique developed at the Joint Institute for VLBI ERIC (JIVE) together with its partners was used for several experiments with several ESA planetary science missions. It has been chosen by ESA as one of the eleven experiments of the Jupiter Icy Moons Explorer (JUICE), the first Large-class mission in the ESA’s Cosmic Vision 2015–2025 program. The mission is scheduled for launch in 2022.

Figure 1: A typical PRIDE Experiment  

1. PRIDE for JUICE Mission

PRIDE is a multidisciplinary component of the JUICE science suite. The main measured deliverables of PRIDE are lateral coordinates L(φ, θ) of spacecraft and the radial velocity of spacecraft. The former (main) measurable of PRIDE requires the phase-referencing VLBI observations (see Duev et al. [1]).  The latter employs the Doppler extraction technique described in [7,8]. Its prime deliverable will be used primarily for improvement of the Jovian system ephemerides in support to a variety of applications, ranging from gravimetry to geodynamics to fundamental physics. A typical PRIDE experiment is shown in Figure 1.

PRIDE observations are carried out by the ground segment when the spacecraft emits a radio signal for communication or radio science purposes. The methodology of PRIDE has been demonstrated with the ESA's Venus Express & Mars Express by Duev et al. 2012 [1], Molera Calvés et al. 2014 [2], Duev et al. 2016 [4], Molera Calvés et al. 2017 [8], Bocanegra et al. 2018 [7], Bocanegra et al. 2019 [8]. In addition to nominal science objectivities, the team is considering ad hoc observations around the Venus and Mars flybys during the cruise phase. A covariance analysis for a broad scope of the PRIDE measurable and Jovian system parameters have been performed to optimize the observation planning and the overall science impact of the JUICE mission (Dirkx. D et al. 2016 [4] & Dirkx. D et al. 2017 [5]).

2. Ongoing PRIDE observing projects

In 2020, we have begun a campaign to gather PRIDE tracking data of the InSight lander, with up to three tracking epochs scheduled for each of the three 2020 EVN sessions. The primary goal of these experiments is to serve as a preparatory activity for more intensive operations for ExoMars-LaRa [9].

The primary manner in which PRIDE will be able to contribute to the science objectives of LaRa is through the use of the Doppler data obtained by all receiving stations. As shown by the analysis of Bocanegra et al. 2018 [7], PRIDE Doppler data at X-band is similar, and in some cases, higher quality compared to regular closed-loop tracking data. One advantage of PRIDE lies in its diversity of receiving stations, making the data quality much less dependent on the meteorological or operational conditions at a single telescope.

Figure 2:  Frequency detections of Mars Insight (NASA) as seen from the University of Tasmania network of radio telescopes. The spacecraft signal was detected at the sky frequency of 8407.25 MHz and Doppler shift of 50 kHz along 70 minutes of tracking

Besides, we propose to merge the three-way Doppler data generated at each receiving station, to fully exploit the data encoded in all downlinks. This would allow an improved calibration of receiving station noise levels, as the noise incurred locally at the receiving ground station (including Earth tropospheric and ionospheric noise on the downlink) is independent for each station. We will use the InSight tracking data to test different practical approached to achieving this conceptual aim, and apply these ‘lessons learned’ to ExoMars-LaRa data analysis. In particular, we will apply the InSight tracking data to investigate different manners in which to weigh the data, considering the fact that the three-way Doppler noise generated at all receiving stations is highly correlated, and to investigate how inter-station biases and drifts can best be calibrated for. The results of the ongoing PRIDE observations of NASA's InSight probe will be reported elsewhere (Dirkx. D, Le Maistre. S, Dehant. V et al., in preparation).

References

How to cite: Pallichadath, V., Bahamon, T. B., Cimò, G., Dirkx, D., Duev, D., Gurvits, L., Calvés, G. M., and Vermeersen, B.: PRIDE: Ground-based VLBI observations for Spaceborne Probes , Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-647, https://doi.org/10.5194/epsc2020-647, 2020.

Different mass spectrometric approaches have been used to study the composition of ice and dust particles in space. Mass spectrometers onboard spacecraft such as Cassini, Rosetta and Giotto at Saturn, comet Churyumov-Gerasimenko and comet Halley respectively, have expanded our understanding of these planetary bodies by probing the composition of their dusty environments (Grün et al. 2019). The outstanding results from different space missions prove in situ mass spectrometry to be a reliable analytical tool with which to investigate the Solar System. Many of the mass spectrometers flown through the Solar System have used the impact ionisation technique, and an impact ionisation mass spectrometer, the Surface Dust Analyzer (SUDA), will be a part of NASA’s upcoming Europa-Clipper mission to Jupiter’s moon Europa. During the impact ionisation process, ice and dust grains impinging onto a detector’s solid target plate, at speeds above ≈ 1 km/s, generate a cloud of ions, neutrals and electrons (Srama et al. 2004; Auer & Sitte (1968)). The ions (cations in this work) are accelerated through a drift or reflectron region, towards a detector, from which time of flight mass spectra are generated (Friichtenicht et al. 1971).

Electrostatic accelerators are used to calibrate (Mocker et al. 2012) impact ionization mass spectrometers on Earth, accelerating micron and submicron cosmic dust analogue grains, typically metallic or with a conductive coating, to suitable velocities. As the controlled acceleration of µm-sized ice grains to these hypervelocities is not yet possible in the laboratory, an analogue experiment using Laser Induced Liquid Beam Ion Desorption (LILBID), is employed to simulate the impact ionisation process of ice grains in space (Klenner et al. 2019). In the LILBID process, a thin stream of an aqueous solution of, for example, organic compounds is exposed to laser irradiation in a vacuum. The dissolved compounds, together with the solvent matrix, are ionized and fragment when the matrix, in which charges are stochastically distributed, is dispersed (e.g. Wiederschein et al. 2015). By varying the laser power, as well the ion collection efficiency, it is possible to simulate the spectra which result from impact ionisation at varying impact speeds (Wiederschein et al. 2015, Klenner et al. 2019). The resulting cation time of flight mass spectra then contain mass spectral features corresponding to organic fragments and water cluster species. This technique has been successfully used (Postberg et al. 2009, 2018; Khawaja et al. 2019) to simulate the mass spectra produced when Cassini’s Cosmic Dust Analyzer (CDA) sampled salt- and organic-bearing ice grains emitted into space by Saturn’s moon Enceladus.

In this work we present a comparison between the mass spectral features of organic molecules generated by LILBID simulation of the impact ionisation mass spectra of organic-bearing ice grains, and the widely used standard technique of electron ionization (EI), the results of which can be found in existing databases, such as the National Institute of Standards and Technology (NIST) Chemistry WebBook.  In electron-ionisation (EI), the sample is directly exposed to a beam of high-energy electrons (≈ 70 eV) which converts neutral molecules into molecular ions (M⁺) with high internal energies. Owing to the generated energies, the structures of the molecular ions become unstable and break up, producing a characteristic population of fragment ions. We have compared the cationic fragments of isomeric carbonyl compounds measured with LILBID and with those from EI obtained from the NIST WebBook database. The tested compounds are divided into three pairs of aldehydes and ketones i.e., propanal & acetone, butanal & 2-butanone, hexanal & 2-hexanone, with 3, 4 and 6 carbon atoms, respectively. To compare the spectral features related to organic fragments, water-cluster features are excluded from the LILBID spectra. In most cases, both the LILBID and EI spectra of the compounds show typical cleavage patterns characteristic of carbonyls.

In ketones and aldehydes, for both LILBID and EI, we observe a correlation between the number of parent molecule carbon atoms and the relative intensities of particular cation fragments. We will present an in-depth comparison of the spectral features obtained from these techniques is currently, using LILBID spectra obtained for a mass spectral database applicable to the SUDA instrument on NASA’s Europa Clipper mission. The mass spectrometers (MASPEX & PEP-NIM) onboard Europa-Clipper, and ESA’s Jupiter Icy Moon Explorer (JUICE) spacecraft, respectively, will employ an EI (70 eV) technique, and the work presented here provides a valuable comparison and cross-calibration between the well-known EI and the more esoteric impact ionization techniques. Understanding the differences between the EI and impact-induced fragmentation and ionization behaviour of organics may also allow large existing libraries of EI spectra to be used to interpret the in situ impact ionization mass spectra of ice-free grains, such as those expected to be returned by JAXA’s Destiny+ mission to the unusual active asteroid 3200 Phaethon, progenitor of the Geminid meteor shower.

References

Grün, E., Krüger, H., & Srama, R. (2019) The dawn of dust astronomy, Space Sci Rev, 2015:46.

Srama, R. et al. (2004). The Cassini cosmic dust analyzer. Space Sci Rev, 114(1– 4), 465–518.

Auer, S., & Sitte, K., (1968). Detection technique for micrometeoroids using impact ionization. Earth and Planetary Sci Lett, 4,178–183

Friichtenicht, J. F., Roy, N. L., & Moede, L. W. (1971). Cosmic Dust Analyzer. Technical Report NASA2CR2140241.

Mocker, A. et al (2012). On the applicability of laser ionization for simulating hypervelocity impacts. Journal of Applied Physics, 112(10).

Klenner, F. (2019), Analogue spectra for impact ionization mass spectra of water ice grains obtained at different impact speeds in space, Rapid Communications in Mass Spectrometry, 33(22), 1751–1760.

Wiederschein, F. et al. (2015) Charge separation and isolation in strong water droplet impacts. Physical Chemistry Chemical Physics. PCCP, 17(10), 6858–64.

Postberg, F. et al. (2009) Sodium salts in E ring ice grains from an ocean below the surface of Enceladus. Nature, 459, 1–4.

Postberg, F. et al. (2018) Macromolecular organic compounds from the depths of Enceladus, Nature, 558(7711), pp. 564–568.

Khawaja, N. et al. (2019) Low-mass nitrogen-, oxygen-bearing, and aromatic compounds in Enceladean ice grains, Monthly Notices of the Royal Astronomical Society, 489(4), pp. 5231–5243.

How to cite: Khawaja, N., Hillier, J., Klenner, F., Nölle, L., and Postberg, F.: Comparative Study of Mass Spectrometry Techniques Relevant to Current and Future Space Missions, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-827, https://doi.org/10.5194/epsc2020-827, 2020.

Abstract

The Ganymede Laser Altimeter (GALA) is one of ten instruments selected for ESA’s Jupiter Icy Moons Explorer (JUICE) mission. We will present an overview on the scientific goals as well as on the status of the instrument development and performance analysis.

ESA’s JUICE mission will explore Jupiter, its magnetosphere and satellites first in orbit around Jupiter before going finally into polar orbit around Ganymede [1]. GALA is one of ten payloads on-board the spacecraft and is developed under responsibility of the DLR Institute of Planetary Research in collaboration with industry and institutes from Germany, Japan, Switzerland and Spain. Its major objectives are to measure the surface topography and the tidal deformation of the satellite.

JUICE (Jupiter Icy Moons Explorer) will be the first orbiter around a moon (other than Earth’s moon) in solar system exploration. Its launch is planned for May/June 2022 followed by an interplanetary cruise of 7.6 years. Jupiter orbit insertion will take place by the end of 2029. An orbit maneuver will bring the spacecraft into a 500-km circular orbit in which it will be staying for at least 132 days until end of nominal mission. The latter phase will be the main period for GALA taking data. In addition data will be taken at Europa, Ganymede, and Callisto at closest approaches of flybys in the Jupiter orbiting phase.

GALA has two main objectives: (1) by range measurements it shall obtain Ganymede’s topography on global, regional and local scales. This will reveal how surface features have formed and how they are connected with the shallow interior ice shell. Global shape measurements will tell us whether the satellite is in hydrostatic state with respect to rotational and tidal forces. (2) Obtaining range measurements distributed in time along the orbital cycle, tidal variations of surface elevations will be measured. The tidal amplitudes are indicative for the presence of a subsurface ocean and would (together with complementary measurements) constrain the ice-I shell thickness [2].

GALA is a single-beam altimeter: a laser pulse (at 1064 nm wavelength) is emitted by using an actively Q-switched Nd:YAG laser firing at 30 Hz in nominal operation. A small fraction of the pulse is guided through fiber optics onto the detector characterizing the outgoing pulse and time of emission. After about 3 msec the Lambertian reflection of the pulse from the surface is received by a aperture telescope and transferred to the detector, an Avalanche Photo Diode. The signal is digitized at a sampling rate of 200 MHz and transferred to the range finder module, which determines (a) the time of flight between the emission and receiving of the pulse (b) the pulse shape, in particular the pulse-width, and (c)  the energy of the received pulse. From the time of flight of the wave-package and the spacecraft position and attitude, the distance for each shot can be converted into height above a reference surface in post-processing of the data.

 (1)           (2)

(3)

Figure 1: (1) GALA Tranceiver, (2) Electronics Unit (ELU), (3) Laser Electronics Unit (LEU)

In 2019 the GALA EM (Engineering Model) was delivered to Airbus Defence and Space Toulouse and was successfully integrated into the JUICE EM and tested. The EM is used to test the functionality of GALA; it can be operated only under ambient conditions. Later it will be used as a ground reference model for checks for the Flight Model.

For the GALA  delivery in 2021 the different GALA flight model subsystems are currently  tested and integrated at  DLR, and at industries in Japan (Meisei) and Germany (Hensoldt Optronics). Flight hardware of the Power converter Module (PCM) and the Range Finder Module have been received from our partner institutes in Spain (IAA, CSIC) and  Switzerland (UBE). The main units of GALA are the TRU, the LEU and the ELU, see Figure 1. The TRU consists of the laser/detector system, including an Avalanche Photo Diode. ELU includes the main CPU, Data Processing Module, Range Finder Module for the analysis of the laser pulses and the Power Converter Module which provides the power. A detailed description of GALA can be found in [3]. All parts were tested in terms of functionality and performance, here in particular the detector.  Besides electrical testing a big part is the testing of the on-board software, the Application Software. Mainly it manages the commanding of the above mentioned parts, the memory management, FDIR (Fault Detection Isolation Recovery) and the interface (I/F) to the spacecraft (S/C). For I/F testing to the S/C a SIS (Spacecraft Interface Simulator) is used to check the GALA commanding and the data output.

After testing at DLR the above mentioned GALA parts will be assembled to the GALA PFM at Hensoldt Optronics Oberkochen. Here additional tests will take place like thermal vacuum tests, EMC and further functional testing, especially for the laser system, but also for the complete system before it will be delivered for final integration into the JUICE spacecraft in 2021.

[1] Grasset, O. and 17 colleagues (2013), JUpiter ICy moons Explorer (JUICE): an ESA mission to orbit Ganymede and to characterise the Jupiter system, Planet. Space Sci., 78, 1-21.

[2] Steinbrügge, G., A. Stark, H. Hussmann, F. Sohl, and J. Oberst (2015), Measuring tidal deformations by laser altimetry. A performance model for the Ganymede Laser Altimeter, Planet. Space Sci., 117, 184-191.

[3] Hussmann, H. and 38 colleagues 2019. The Ganymede Laser Altimeter (GALA): key objectives, instrument design, and performance. CEAS Space Journal (Special Issue on Space Lidar and Space Optics) 11, 381 – 390.

How to cite: Luedicke, F., Hussmann, H., Lingenauber, K., Kallenbach, R., Enya, K., Kobayashi, M., Thomas, N., and Touhara, K.: Exploring the icy moons of Jupiter: The Ganymede Laser Altimeter (GALA) for ESA’s JUICE Mission, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-1076, https://doi.org/10.5194/epsc2020-1076, 2020.

In-situ Mars exploration requires new promising instrumentation that will be capable of delivering highly accurate chemical information about soils and rocks present at the Martian surface. Specific attention is drawn to the instruments that are capable of identifying extinct or extant microbes within the bulk of various solid samples (Tulej et al., 2015; Westall et al., 2015; Wiesendanger et al., 2018). A miniature Laser Ablation/Ionization Mass Spectrometer (LIMS) developed at the University of Bern is among the valid candidates (Wurz et al., 2012). The size of the mass analyzer is only Ø 60 mm × 160 mm and thus capable of being deployed on a rover or lander platform. In this contribution, we will present data collected from a 1.88 Ga Gunflint sample using a deep UV fs laser system as ablation ion source. The gunflint chert sample contains a population of microfossils entombed in the silica matrix and was chosen as a Martian analogue. Using the high stability of the UV laser and consequent uniform ablation, we performed large-scale spectra collection (90’000) in two modes - chemical imaging and depth profiling. With the current setup, we achieved a diameter of the analytical spot of ~10 µm for the depth profiling and ~5 µm for the imaging. Our results reveal that our LIMS instrument can identify the location of the microfossil lamination area as well as single microfossils by chemical means. We show how single mass unit spectral decomposition and subsequent kernel clustering reveal masses and intensity regions unique to the microfossils and inorganic host, thus providing the opportunity for automated identification of the spectra that are collected from the microfossils. We also show how transforming spectral intensities into spectral proximities can help to navigate the rich multidimensional datasets. We also address common interpretation problems in LIMS, when multiple mineralogical inclusions contribute to the output spectra acquired within the single analytical spot using ρ-networks and Principal Component Analysis (PCA). In combination with analysis of spectral proximities, this approach is particularly useful in attempts to assess the biogenicity of the putative terrestrial microfossils as well as potential Martian microfossils. Additionally, we discuss the data analysis pipeline and chemical composition of the microfossils and surrounding inorganic host in detail. 

Tulej M., Neubeck A., Ivarsson M., Riedo A., Neuland M. B., Meyer S., and Wurz P. (2015) Chemical Composition of Micrometer-Sized Filaments in an Aragonite Host by a Miniature Laser Ablation/Ionization Mass Spectrometer. Astrobiology, 15: 669-682.

Westall F., Foucher F., Bost N., Bertrand M., Loizeau D., Vago J. L., Kminek G., Gaboyer F., Campbell K. A., Bréhéret J.-G. and others. (2015) Biosignatures on Mars: What, Where, and How? Implications for the Search for Martian Life. Astrobiology, 15: 998-1029.

Wiesendanger R., Wacey D., Tulej M., Neubeck A., Ivarsson M., Grimaudo V., Moreno-García P., Cedeño-López A., Riedo A., Wurz P. and others. (2018) Chemical and Optical Identification of Micrometer-Sized 1.9 Billion-Year-Old Fossils by Combining a Miniature Laser Ablation Ionization Mass Spectrometry System with an Optical Microscope. Astrobiology, 18: 1071-1080.

Wurz P., Abplanalp D., Tulej M., Iakovleva M., Fernandes V. A., Chumikov A., and Managadze G. G. (2012) Mass spectrometric analysis in planetary science: Investigation of the surface and the atmosphere. Solar System Research, 46: 408-422.

How to cite: Lukmanov, R., Tulej, M., Riedo, V., Ligterink, N., De Koning, C., Riedo, A., and Wurz, P.: In-situ analysis of 1.9 Ga chert with a miniature mass spectrometer for space, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-195, https://doi.org/10.5194/epsc2020-195, 2020.

1 Introduction

The increasing interest in Laser-induced breakdown spectroscopy (LIBS) for space-exploration is confirmed by two more LIBS instruments, SuperCam aboard NASA’s Mars 2020 mission and MarsCoDe as part of China’s Tianwen 1 mission, being launched towards Mars this summer [1, 2]. SuperCam will be the follow-up of the ChemCam instrument, which has been successfully analysing the Martian surface since its landing in 2012 [3]. In 2019, another LIBS instrument has been launched heading for the Moon [4], but did unfortunately not accomplish a soft landing.

LIBS is a fast and versatile elemental analysis technique. It is based on laser ablation and needs only optical access to the target. For LIBS, a laser pulse is tightly focused onto the sample, where a small portion of material is ablated and excited into a plasma of neutral atoms, ions and electrons. The plasma emits continuum radiation from bremsstrahlung and electron-ion recombination, together with discrete emission lines from the species in the plasma. The latter allow for identification of the chemical elements contained in the plasma, and therefore in the sample.

2 Challenging elements in LIBS

In general, all elements of the periodic table are detectable with LIBS. Some of them, however, have their strongest emission lines outside of the typically observed spectral range from approx. 240 to 800 nm. As the emission intensity of a spectral line strongly depends on, amongst other factors, the population density of the transition’s upper level, transitions between lower energy levels are typically strong. For neutral S, the fundamental ground state transition is located at 180.7 nm, while Cl atoms have their strong ground state transitions between 133 and 138 nm. Both elements are therefore expected to be well detectable in the vacuum-UV (VUV) range below 200 nm.

3 VUV-LIBS

VUV-LIBS means the emission of the plasma is detected in the VUV spectral range. In terrestrial environment, this range is obscured due to absorption by O₂ and H₂O vapour from the atmosphere. VUV absorption in CO₂ and CH₄ further reduces the applicability of VUV-LIBS on e.g. Mars or Titan. For celestial bodies without a significant atmosphere, however, the predicted high emission intensities in the VUV range for otherwise challenging elements like S and Cl could be exploited to increase the sensitivity for these elements.

One drawback of LIBS in a very low pressure environment is the short life time of the plasma and its relatively low intensity. While the reduced atmospheric pressure on Mars in the order of 1 kPa is beneficial for LIBS and produces a large and bright plasma, the low confinement and therefore low probability for collisions of the plasma species at below 10 Pa leads to a short-living and dim plasma [5]. Thus, the sensitivity of LIBS in vacuum is naturally lower, and it could be even more crucial for mission instruments on bodies without atmosphere to make use of the stronger VUV emission lines.

VUV-LIBS is readily used in industrial applications, e.g. for S detection in steel [6]. There, laser pulse energies of several hundreds of millijoules, multi-pulse configurations, and purge gas atmospheres are used to compensate for atmospheric absorption and the reduced emissivity of vacuum plasmas, thereby yielding limits of detection in the order of 10-100 ppm. For space exploration, VUV-LIBS has not yet been extensively studied. Radziemski et al. investigated the applicability of VUV-LIBS for use on Mars, using components realistic for a mass-, size- and power-constrained space instrument [7]. They noted significant suppression of the strongest Cl lines in the 130-140 nm range due to the CO₂ atmosphere, while at the same time benefiting from the LIBS-favourable pressure.

4 Experimental Details

Our set-up is built around a H+P vacuum spectrometer covering the range of 100-300 nm, see Figure 1. The plasma is excited with a pulsed Nd:YAG laser (1064 nm, up to 40 mJ, 6 ns), which is focused vertically onto the sample. The sample is contained in a vacuum chamber, directly flanged to the spectrometer. The radiation emitted by the plasma is coupled into the spectrometer using an off-axis parabolic mirror. The mirror currently limits the spectral range to >120 nm. The whole system is operated at a pressure of ≤1 mPa.

The samples analysed in this study are lunar simulants (Exolith LHS-1 and LMS-1 [8]) mixed with different amounts of pure sulfur, different sulfates, or sodium chloride. They have been prepared in-house using mortar and pestle, and a hydraulic press. The resulting atomic fractions of S and Cl range from 0.5 to 4.0 %.

5 Results

We successfully detected S in lunar simulant matrices, using the S I emission line at 180.7 nm. Example spectra for Na₂SO₄ in LHS-1 at 0.5 and 1.6 at% S are shown in Figure 2. Besides Al, Si and O emission lines from the matrix material, the S I emission line is clearly visible already at those low concentrations. Univariate calibration curves suggest a linear relationship between S concentration and emission intensity for low concentrations.

The Cl I emission lines around 135 nm spectrally overlap with Si II emission, but a change in their intensity upon changes in the Cl concentration is still recognizable.

6 Summary and Conclusion

S and Cl have been detected in lunar simulant matrices at atomic fraction levels in the order of 1 %. For low concentrations of S, we found a linear relationship between S concentration and LIBS signal with a univariate approach. These results are promising for improved detectability of volatiles in space exploration, which are usually hard to detect with conventional LIBS in the spectral range of 240-800 nm. Besides S and Cl, emission lines of Al, Fe, Si and O have been identified.

References

[1] Wiens et al., Spectroscopy, 32, 5 (2017).

[2] Ren et al., EPSC2018, id EPSC2018-759-2 (2018).

[3] Maurice et al., J. Anal. At. Spectrom., 31, 863 (2016).

[4] Laxmiprasad et al., Advances in Space Research, 52, 332 (2013)

[5] Knight et al., Applied Spectroscopy, 54, 331 (2000).

[6] Sturm et al., Applied Spectroscopy, 54, 1275 (2000).

[7] Radziemski et al., Spectrochim. Acta B, 60, 237 (2005).

[8] Britt and Cannon, NESF2019, 82 (2019).

How to cite: Kubitza, S., Schröder, S., Dietz, E., Frohmann, S., Hansen, P. B., Rammelkamp, K., Vogt, D. S., Gensch, M., and Hübers, H.-W.: Sulfur and Chlorine Detection in a Lunar Context Using VUV-LIBS, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-806, https://doi.org/10.5194/epsc2020-806, 2020.

Introduction: Simultaneous, distributed in situ measurements would benefit scientific investigations of both Mars and Moon. On Mars the global and related local phenomena such as atmospheric circulation patterns, boundary layer phenomena, water, dust and climatological cycles and investigations of the planetary interior would be ideal objects for in situ network studies. On the Moon the possibility of using an network of sensing platforms will enable the study the formation of the Solar System based on the Moon evolution, by dating craters and basins as well as to the study of the Lunar interior as the evolution of a differentiated planetary body. Such observation networks would require miniature low-mass landers, with a suite of sensors for a range of scientific measurements. We present an ESA study named “MiniPINS” to develop suitable sensor packages for aforementioned purposes.

The MiniPINS study: MiniPINS is an ESA study led by the Finnish Meteorological Institute to develop and prototype miniaturised surface sensor packages (SSPs) and their delivery methods for Mars and the Moon. The study aims at miniaturising the scientific sensors and subsystems, as well as identifying and utilizing commonalities of the packages, allowing to optimise the design, cut costs and reduce the development time. The 1.5-year study began in January 2020 and is currently in phase A. So far multiple different concepts for both Mars and Moon have been investigated, including a separating forebody for Mars penetrator and power systems with and without RHU for Moon SSP, and several trade-off analysis have been performed to select the concepts that fulfill the mission needs and scientific goals. The selected concepts will be presented in EPSC 2020.

Mars sensor package: The Mars SSP will be a small 25 kg penetrator deployed from a Mars orbiter. Four (4) penetrators will be carried to the Martian orbit by an orbiter and the orbiter will be oriented for deployment of each penetrator. The SSP’s can be delivered to Mars for example by Mangalyaan-2 or MMX and no dedicated orbiter for the SSP’s is foreseen. In the Martian atmosphere the penetrators undergo aerodynamic braking until they reach the target velocity for entering the Martian surface. The SSP is utilizing inflatable state-of-the-art entry, descent and landing (EDL) technologies, heritage from MetNet Lander development [1]. The shock-absorption system limits the deceleration experienced by the payload during landing impact utilizing mechanical deformation. The SSPs will start their scientific observations after landing and stay stationary throughout their nominal mission of 2 years. The SSPs have an ambitious science program and their payloads consist initially of a camera, a visual spectrometer, a meteorological package, an accelerometer, thermoprobes, a magnetometer, a chemistry package and a radiation monitor. The SSP will also provide positioning signal and communications link to the orbiter. The final scientific case will be selected throughout the study.

Moon sensor package: The Moon SSP will be a miniature 5 kg station deployed on the Moon surface by a rover. Four (4) SSPs are deployed from a rover with low velocity and small impact depth (max. 0.05 m). The Moon SSP is a good match to be delivered by the European Large Logistic Lander (EL3) which is a part of the ESA-led HERACLES mission [2]. The proposed landing site for the HERACLES is the Schrödinger crater, located at the South Pole Aitken Basin. The Moon SSP utilizes an European Radioisotope Heating Unit (RHU) [3] to survive the Lunar night, when the surface temperature will reach the minimum of -170°C, and to provide thermalization for the system electronics such as batteries, and for the scientific instruments. The RHU also enables to select from wider variation of landing locations compared to using only solar panels as an energy source. The SSPs will start their scientific observations after landing and study for example radiation, seismology, magnetic field and chemistry. SSP will also provide communications link to a relay orbiter. Some instruments such as the camera, the accelerometer, thermoprobes, the magnetometer, the radiation monitor and the seismometer, can be common between both Mars and Moon packages and the possibility is investigated during this study.

Summary: Both Mars and Moon SSPs will be miniaturised, light and robust, and still capable of surviving high G loads (Mars SSP) and extreme thermal environments. SSPs are capable of working on the surface of Mars or Moon for at least 2 years and to produce high quality science data with state of art instrumentation. The critical technologies identified in this study so far include the development of inflatable aerodynamic devices, shock and penetration testing of the Mars SSP and dimensioning of energy needs and identification of harvesting and storage technologies, as well as the definition of ultra-low power operation modes. The output of this work will enable ESA to prepare and plan for technology development programs required to implement such ambitious planetary missions.

References: [1] Harri A-M et al. (2017), Geosci. Instrum. Method. Data Syst. 6, 103-124. [2] Hiesinger H. (2019), Lunar and Planetary Science Conference, 1327. [3] Ambrosi, R. M. (2019), Space Science Reviews 215, 55.

How to cite: Hieta, M., Genzer, M., Haukka, H., Kestilä, A., Arruego, I., Apéstigue, V., Martínez, J., Reina, M., Ortega, C., Camañes, C., Sard, I., Dominguez, M., Espejo, S., Guerrero, H., Rodríguez Manfredi, J. A., Talvioja, M., Kivekäs, J., Koskimaa, P., and Palin, M.: MiniPINS - Miniature in situ sensor packages for Mars and Moon, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-858, https://doi.org/10.5194/epsc2020-858, 2020.