Europlanet Science Congress 2020
Virtual meeting
21 September – 9 October 2020
Europlanet Science Congress 2020
Virtual meeting
21 September – 9 October 2020

Oral presentations and abstracts

MITM3

Together with the recent Discovery and New Frontiers missions’ selections, a good number of ESA, JAXA, ISRO .. planetary missions and flight instruments are either in development or have been proposed and in review. Mission or instrument leads and/or team members are encouraged to present their missions or instruments for wider community awareness, lessons learned or for fostering future collaborations. Abstracts on concept planetary missions and instruments can also be considered for this session

Convener: Brook Lakew | Co-conveners: Olivier Mousis, Geronimo Villanueva, Stephanie A Getty, David H. Atkinson, Sami Asmar, Daniele Durante, Silvia Tellmann, Axel Hagermann, Nicholas Attree, Günter Kargl, Mark Paton

Session assets

Session summary

Chairperson: Brook Lakew, Geronimo Villanueva
EPSC2020-311ECP
Marco Pinto, Patrícia Goncalves, Wojciech Hajdas, and Patryk Socha

The JUpiter ICy moons Explorer (JUICE) is the European Space Agency (ESA) next large class mission to the Jovian system. The mission, scheduled to launch in 2022, will investigate Jupiter and characterize its icy moons, Callisto, Europa and Ganymede for a period of 3.5 years after a 7.5-year cruise to the planet. JUICE is planned to flyby Europa and Callisto, perform a high latitude tour of the Jovian system, and finally, at the end of the mission, it will orbit Ganymede at different altitudes inside the moon’s intrinsic magnetosphere.

While radiation is one of the major threats for all Space missions, in the Jovian system this problem is exacerbated due to the existent of very large fluxes of energetic electrons, with energies up to dozens of MeV, which can damage and eventually destroy the spacecraft systems. The existence of this electron population, and to a lesser extent of a proton and heavy ion population, is a consequence of Jupiter’s huge magnetosphere which can accelerate these particles to energies higher than those found in other known planetary magnetospheres. Although the Galileo mission, and to a lesser extent the Cassini, Pioneer and Voyager missions have provided ample information about the radiation environment in the Jovian, several questions about particle origin, acceleration mechanisms, Jovian-Solar magnetosphere coupling, and overall dynamics of the system still need to be answered with implications in magnetospheric physics, astrobiology and others, as well as in development of future manned and unmanned missions to both the inner and outer Solar System.

For these reasons, the JUICE mission will include the RADiation hard Electron Monitor (RADEM), a low power, low mass radiation monitor, that will increase the range of long-term spectral measurements acquired by the Energetic Particle Detector (EPD) aboard the Galileo spacecraft, from 11 to 40 MeV for electrons and from 55 to 250 MeV for protons. RADEM consists of three detector heads based on traditional silicon stack detector technologies: the Electron Detector Head (EDH), the Proton Detector Head (PDH), and the Heavy Ion Detector Head (HIDH), that will measure electrons from 0.3 MeV to 40 MeV, protons from 5 MeV to 250 MeV and Heavy Ions from Helium to Oxygen with energies from 8 to 670 MeV, respectively. Because the detectors have limited Field-Of-View, a fourth detector, the Directionality Detector Head (DDH) will measure electron angular distributions which can vary greatly along the Jovian System as observed by the Galileo spacecraft.

Although RADEM is a housekeeping instrument that will provide in-situ Total Ionizing Dose (TID) measurements and serve as a radiation level alarm, it has a broad scientific potential. Besides the Jovian system, the instrument will be fully operated during the cruise of the Solar System, which includes three Earth flybys, a Venus flyby and a Mars flyby, that offer additional scientific opportunities including but not limited to studying the cosmic ray gradient in the Solar System, characterizing Solar Energetic Particle (SEP) events, and others. In this work, we will present RADEM from a technical point-of-view, as well as the scientific opportunities that will be addressed by the radiation monitor during the JUICE mission.

How to cite: Pinto, M., Goncalves, P., Hajdas, W., and Socha, P.: The RADiation hard Electron Monitor (RADEM) for the JUICE mission, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-311, https://doi.org/10.5194/epsc2020-311, 2020.

EPSC2020-511
Robert Lillis, Shannon Curry, Janet Luhmann, Yingjuan Ma, Aroh Barjatya, Phyllis Whittlesey, Roberto Livi, Davin Larson, Shaosui Xu, Christopher Russell, Christopher Fowler, David Brain, Ed Thiemann, Paul Withers, Ronan Modolo, Yuki Harada, and Matthieu Berthomier

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 flows throughout Mars’ magnetosphere to drive ion and sputtering escape, two processes which have helped shape Mars’ climate evolution over solar system history. 

ESCAPADE will measure magnetic field strength and topology, ion plasma distributions (separated into light and heavy masses), as well as suprathermal electron flows and thermal electron and ion densities, from coordinated elliptical, 200 km x ~7000 km orbits. ESCAPADE are small spacecraft (<150 kg), traveling to Mars via solar electric propulsion as a rideshare with the Psyche metal-asteroid mission in August 2022. ESCAPADE’s strategically-designed 1-year, 2-part scientific campaign of temporally and spatially-separated multipoint measurements within and between the different regions of Mars’ diverse plasma environment, will allow the cause-and-effect of solar wind control of ion and sputtering escape to be unraveled for the first time. Figure 1 shows ESCAPADE’s orbits within a hybrid simulation of the solar wind interaction with Mars, where the color scale represents ion velocity, blue lines are magnetic field, while white lines are sample proton trajectories and spacecraft orbits.

ESCAPADE is due to complete its preliminary design review in August 2020, thereafter moving toward build, test, integration and launch two years later.  We will report on science goals and objectives, mission design challenges, and provide a status update.

How to cite: Lillis, R., Curry, S., Luhmann, J., Ma, Y., Barjatya, A., Whittlesey, P., Livi, R., Larson, D., Xu, S., Russell, C., Fowler, C., Brain, D., Thiemann, E., Withers, P., Modolo, R., Harada, Y., and Berthomier, M.: ESCAPADE: Coordinated multipoint measurements of Mars' unique hybrid magnetosphere, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-511, https://doi.org/10.5194/epsc2020-511, 2020.

EPSC2020-575ECP
Kristie LLera and the NASA 31st PSSS group

Abstract: The study of exoplanets is essential to expanding our understanding of solar system formations, as well as, the development of life in the universe [1]. Unfortunately, with the vast distances between stars, we observe limited aspects of these exoplanetary systems by telescope. With the recent discovery of two interstellar objects (ISOs), one volatile-poor (1I/’Oumuamua [2]), and one volatile-rich (2I/Borisov [3]), we can detect and observe exoplanetary material bound for our solar system. We propose a new mission concept (Bridge) to flyby a yet-to-be-discovered ISO as it passes through our inner solar system. Bridge is feasible under NASA’s New Frontier’s class-mission; however, it will require changes to future NASA Announcements of Opportunity (AO) to provide long-term spacecraft storage and rapid launch response capabilities. While other ISO mission concepts require long-term missions as the ISO encounter occurs outside our solar system, Bridge is designed for an ISO encounter within 0.7-2 AU; streamlining the architectural design. Bridge would provide a unique opportunity to gain insight into physical, chemical, and biological differences between our solar systems as well as transport of planetary materials between them. An active community of ground-based surveys is key to catching potential targets. NASA ground-based telescope campaigns are awarded independently of mission AO. Providing an option to include ground-based observation time to secure the needed resources for optimum mission success, would be advantageous for these once-in-a-lifetime encounters. Bridge was designed during NASA’s 31st Planetary Science Summer Seminar [4].

Science goals & objectives: Bridge has two science goals: (1) determine whether prebiotic chemical ingredients can be transported between stellar systems and the interstellar medium, and (2) determine if interstellar objects form via the same processes as objects within our solar system. To address the first goal, Bridge would look for spectral signatures from CH, N2, polycyclic aromatic hydrocarbons, and tholins. To address the second goal, Bridge would compare its elemental abundances, isotope ratios, and relative abundances of noble gases to those of other solar system objects and presolar grains (e.g. [6]). Bridge would also look for the presence of ices, the molar abundances of minerals, and the morphological properties of the ISO to 10 m resolution in order to determine if the ISO is similar to any objects in our own solar system.

Science payload: Bridge’s instrument payload can address the aforementioned science goals and objectives regardless of the specific properties of the target ISO. Bridge utilizes a remote sensing suite consisting of a mid-infrared spectrometer, a near-infrared spectrometer, an ultraviolet/visible spectrometer, and a visible light camera. Bridge also employs a battery-powered guided impactor, based on the impactor from Deep Impact [7], to expose the ISO’s interior material. Table 1 lists the instruments and their properties. The high relative encounter velocities of our mission preclude direct in-situ sampling. All instruments in our selected payload are based on previously flown instruments.

Mission design: Bridge is designed to flyby a yet-to-be-discovered ISO. Multiple telescopic survey facilities exist that scout the sky for Near-Earth Objects, comets, and possible ISOs. It is estimated that ≈0.2 ISO detections should occur per year, and when future survey telescopes such as the Large Synoptic Survey Telescope become operational, the number of ISO detections should improve to ≈1 per year [8]. Bridge is designed to wait in storage on Earth until a suitable ISO is detected.

Bridge requires three criteria to be satisfied for a successful ISO flyby: (1) the ISO must pass through the ecliptic plane at a distance between 0.7 and 2.0 AU from the Sun (green region in Figure 2), (2) the relative encounter velocity must be less than 70 km/s, and (3) the total launch C3 is less than 60 km2/s2 for the intercept maneuver, which is achievable given the mass of Bridge and an Atlas V 431 launch vehicle. With these criteria, Bridge could encounter 65% of ISOs whose orbital characteristics are predicted by [1]. Figure 2 illustrates a hypothetical encounter with 1I/’Oumuamua that meets all the aforementioned criteria.

In a 70 km/s flyby scenario, the impactor would be released approximately eight hours before the main spacecraft achieved its closest approach. Fifteen minutes later the main spacecraft would perform a deflection maneuver, steering it to a safe closest approach distance of 8000 km. Thirty seconds prior to impact, the IR spectrometer and visible camera would observe the surface composition. The visible camera would capture a video at the time of the impact, at which point the UV spectrometer would image the ejecta plume flash. Following the impact, the spectrometers would continue to take measurements of the plume. All critical science data would be transmitted before the spacecraft’s closest approach to the ISO ninety seconds after impact. The complete encounter timeline is shown in Figure 3.

Recommendations: To enable Bridge in response to the unique and ephemeral nature of ISOs, several technological advancements and policy changes must occur. This includes: improved ground detection capabilities of small bodies, infrastructure to store a spacecraft in a launch-ready state, rapid launch response, and the opportunity to propose a mission that requires these capabilities. The planetary science community must advocate for language explicitly permitting mission architectures that include storage and rapid launch in future NASA New Frontiers, Discovery, and SIMPLEx AO.

Acknowledgments: This work was supported by NASA’s Planetary Science Division and NASA’s Radioisotope Power System program. The information presented about the Bridge mission concept is predecisional and is provided for planning and discussion purposes only. We thank JPL’s A-Team and TeamX for concept development support, and Leslie Lowes and Joyce Armijo for programmatic support.

References: [1] D. Seligman and G. Laughlin. AJ.,155(5):217, 2018. [2] K.J Meech et al. Nat., 552(7685), 2017. [3] P. Guzik et al. Nat. Astronomy, 2019. [4] C.J. Budney et al. LPSC 50, (3225), 2019. [5] National Research Council. The Ntl. Acad. Press, 2011. [6] A. Davis. Proc. of the Ntl. Acad. of Sci.,108(48):19142–19146, 2011. [7] M.F. A’Hearn et al. Sci.,310(5746):258–264, 2005. [8] D.E. Trilling et al. ApJ., 850(2):L38, 2017.

 

How to cite: LLera, K. and the NASA 31st PSSS group: Bridge To The Stars: A Mission Concept And Policy To Enable An Inner Solar System Encounter With An Interstellar Object, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-575, https://doi.org/10.5194/epsc2020-575, 2020.

EPSC2020-714
Josep Maria Trigo-Rodríguez, Esther Mas-Sanz, Jordi Ibáñez-Insa, and Jacinto Alonso-Azcárate

1. Introduction.

The Moon is no longer a goal in itself but a necessary step for the conquest of space. In this work we focus in the composition of Lunar meteorites as the only objects alongside Apollo, and Luna collected samples, that the scientific community has available to first-hand analyze the Moon. Future Artemis sample return missions will provide new samples to continue learning from our satellite. Given its proximity to our planet, our satellite is an ideal planetary body to use it as a space camp for new technology, to establish a space base, and to test space mining. The continuous depletion of Earth resources put special importance on the exploration of extraterrestrial natural resources potential and the feasibility of its exploitation. After many robotic and manned missions, the utilization of lunar resources has been studied for a long time. In-Situ Resources Utilization (ISRU) refers to the generation of materials (for construction, life support, or as propellants) from the available resources on a celestial body that otherwise, would have needed to be brought from Earth [1].

2. Analitical Techniques and Samples

For the present work, four different Lunar achondrites (Lunaites) were studied: Dhofar 1084, Jiddat al Harasis 838, Northwest Africa 2700 and 11444, and Miller Range 090031 (abbreviated in Table 1). Thin sections of each meteorite allow us a characterization of the mineralogy using SEM/EDX and optical microscopy (Fig. 1). In addition, XRD measurements on capillary powder samples of the meteorites are made using a powder diffractomer equipped with a Mo X-ray souce (λ=0.709 Å). This experimental configuration allows us to minimize preferential orientation effects as well as to significantly reduce the X-ray fluorescence signal from Fe, relative to XRD measurements performed with a standard Cu X-ray tube. Finally we perform ICP-MS and ICP-AES of the samples using a similar procedure that in our previous studies of meteorites [2]. Meteorite specimens studied so far are listed in Table 1.

Table 1. Lunar meteorites under study, type, probable origin and Total Known Mass (TKM).

3. Discussion

Like the Lunar rocks, Lunaites provide valuable information about the chemical and mineralogical complexity that can be found in the surface of the Moon. Despite that we don’t know exactly their origin in the Lunar surface, these relatively small rocks provide clues on the processes going on in the surface of the Moon. Among the most fascinating meteorites, JaH 838 is a mingled regolith breccia presenting mare and KREEPy clasts, together with the products of thermal processing: High-Al Si-Poor (HASP) glasses with chondritic metal grains. Another one is the complex melt breccia NWA 11444 containing a wide variety of angular fragments (gabbros and basalts) and variable amounts of flow-banded glass. Crystal fragments consist predominantly of plagioclase, pyroxene, and olivine. Finally the rock also contains a few percent of Fe,Ni metal grains probably reminiscence of the projectiles sculpting the rock (see Fig. 1).

Fig. 1. A kamacite grain set into an anorthite-rich matrix of NWA 11444. 

4. Conclusions.

From our study and having into account our current knowledge of the chemical and mineralogical lunar resources which can be realistically used for ISRU, the following resources are considered [3,4]:

  • Metals hosted in the lunar regolith are mostly due to the continuous impact of chondritic and metallic projectiles with the Lunar surface. As a consequence, the regolith is enriched in minerals such as pyroxene, olivine, ilmenite and native metals such as Fe and Ni. In addition, it can be found hydrated minerals and rare-Earth elements. As most metals are found in the form of oxides (as well as some pure kamacite), it makes their extraction costly energy-wise as these components tend to be chemically stable [3], but their potential use for producing spacecraft parts and in-situ repairs make them more attractive. On the other hand, the extraction of oxygen is especially interesting from a biological point of view: future missions may utilize it for the production of water and other life support processes.
  • Water, probably to be found as ice inside permanently shadowed craters of the polar regions, could be used as rocket fuel and to support life in a Moon base. On the other hand, some regions of the Moon have been hit by carbonaceous chondritic asteroids, rich in clay minerals. These hydrous minerals contain absorbed and bound water. If heated at temperatures ∼100-150 ºC absorbed water can be released and bound water at ∼300 ºC [4].
  • Carbon and other organic compounds are also common in regolith-rich regions of the Moon. There is a dominant flux of CM chondrites [5] that after impact dehydrate and end up as “graphitized” clasts observed in regolith breccias [6]. Furthermore, it has been theorized of an uncertain amount of hydrocarbons could be used for the production of much complex polymers, resins and plastics [1].
  • Finally, solar wind volatiles become also implanted in the Lunar regolith: H, N, C and in particular the He-3 isotope, rare to find on Earth and key for future developments in nuclear fusion.

Conclusions

Lunar meteorites are valuable samples teaching us about the processes going on over the Moon, at the same time that provide clues on the most important minerals for mining. Many different initiatives on how to tackle Lunar resources are taking place: from 3-D printers that previously construct the necessary infrastructure for lunar mining, the utilization of autonomous robots and obviously, the mingle of different proposals according to the exploitation stage. The Lunar surface provides a lot of valuable materials, but a precise know-how is required to successfully exploit them. Then, a careful study of Lunar samples and meteorites will provide significant progress in optimizing ISRU.

Acknowledgements

The authors acknowledge financial support from the Spanish Ministry (PGC2018-097374-B-I00).

References

How to cite: Trigo-Rodríguez, J. M., Mas-Sanz, E., Ibáñez-Insa, J., and Alonso-Azcárate, J.: Moon in-situ resources: clues from the study of Lunar achondrites in preparation for Artemis sample return missions, Europlanet Science Congress 2020, online, 21 Sep–9 Oct 2020, EPSC2020-714, https://doi.org/10.5194/epsc2020-714, 2020.

EPSC2020-70
| MI
David Blake, Richard Walroth, Philippe Sarrazin, Thomas Bristow, Marc Gailhanou, Robert Downs, and Kathleen Thompson

   Introduction: The search for evidence of life or its processes on Mars takes on two major themes: 1), the identification of environments that have or once had the potential to harbor life (habitability); and 2), the detection of morphological or chemical features suggestive of extinct or extant life (biosignatures).  Compositional heterogeneity at the mm-to-100µm scale can reveal geological processes indicative of past or present habitability, and morphological and compositional heterogeneity on a similar length scale can provide evidence of life’s processes.  The Mapping X-ray Fluorescence Spectrometer (MapX) is an arm-based in-situ instrument designed to identify these features on planetary surfaces [1].

 Instrument Description: MapX is a full-field elemental imager capable of analyzing samples in situ without sample preparation. MapX has no moving parts, a 1-cm depth of field, and is designed to utilize 244Cm radioisotope sources, eliminating the need for a High Voltage Power Supply or X-ray tube.  Figure 1 shows a schematic of the instrument, which consists of X-ray / ϒ-ray / α-particle sources, a focusing optic, and a CCD. The focusing lens is an X-ray micro-pore optic (MPO) which focuses X-ray photons 1:1 onto the CCD. The MPO has a large depth of field (~1cm) allowing rough unprepared surfaces to be imaged with minimal loss of resolution. The CCD is read out fast enough (several frames per second) so that each pixel records either a single photon from the sample or background. The number of electron hole pairs generated in a single pixel is directly proportional to the energy of the X-ray photon, and after summing a large number of individual frames, an XRF spectrum is generated for each pixel of the CCD. Each individual 0.3 sec. frame is a complete image; however many frames are necessary to produce quantifiable XRF spectra. Longer collection times will allow for improved signal to noise, but in the event a collection is interrupted the partial data will still yield a complete image.  Downlinked data products include:  Elemental maps 11<Z<40, instrument-selected [2] Regions of Interest (ROI) having common compositions, and quantifiable XRF spectra from ROI.  

Figure 1. Schematic representation of MapX.

Example MapX datasets: rough surfaces, polished stubs, or petrographic thin-sections were imaged first on an EDAX commercial laboratory instrument (~50 µm resolution), then on MapX-III, a third generation prototype of MapX (~150 µm resolution). MapX-III data are collected in vacuum; on Mars, images will be collected at ambient pressure.

Figure 2 shows a partial MapX dataset collected from a quartz sandstone decorated with hematite crystals (similar to magnetite crystals observed on the surface of mudstones by the MSL Curiosity rover).  The instrument nominally collects ~10,000 0.3 second images into an HDF5 data cube.  An unsupervised machine learning algorithm resident on the instrument computer produces ROI comprised of common elemental compositions.  Quantifiable XRF spectra are generated from each ROI, which are analyzed off-line using a fundamental parameters technique.  ROI compositions are used in conjunction with the RRUFF database [3] to determine putative mineralogy.