Hector-Andreas Stavrakakis

Bioregenerative life support systems (BLSS) designed to produce food crops in future crewed missions to the Moon or Mars consider in-situ resource utilisation (ISRU). Lunar regolith is, therefore, in focus for future technologies of farming on lunar bases. We tested germination and early growth of broccoli plants ( Brassica oleracea var. botrytis italica ) in Murashige-Skoog liquid medium with addition of leachate from a lunar regolith simulant. As the additions to growth, differently diluted water and acidic leachates were used. Physiological status of the germinating plants was evaluated by chlorophyll fluorescence parameters related to plant vitality (relative fluorescence decline – Rfd) and photosynthetic performance of photosystem II (1) potential (F _V /F _M ) and (2) effective quantum yield of PSII (Φ _PSII ), photochemical quenching referring to number of open PSII reaction centres. Both water and acidic leachates inhibited plant growth, however, the extent of growth limitation was dilution-dependent. Full inhibition of germination was apparent when undiluted acidic leachate was added. However, 50% dilution (and higher) resulted in seed germination and the early growth. No negative effects of the water dilutions on F _V /F _M as well as Φ _PSII , were apparent in 15 days old plants, their cotyledonary and the first primary leaves, in particular. Similarly, qP and Rfd showed no sign of either water or acidic leachate addition effect. Although photosystem II-related parameters exhibited no negative effect of the leachates addition, a growth of plants was found dilution-dependent: higher degree of dilution resulted in a more pronounced reduction in plant projection area. In spite of the growth rate reduction (compared to untreated control), properly diluted water and acidic leachates from lunar regolith and/or its simulants might be used in follow up studies focused on plant species prospective for future cultivation in Moon-based stations with temporary or permanent crew.

The study of astrobiology, in particular testing concepts for searching for biosignatures in extraterrestrial environments or conducting experiments for survivability of microorganisms in extraterrestrial materials and conditions, but also the branch of science and engineering focusing on testing instruments in planetary environments or identifying materials and energy resources (ISRU), both require analogue studies with simulated extraterrestrial materials. Thus, the development of accurate and representative simulant regoliths and soils is crucial [1]. In this study, we present new Martian simulants that have been developed to expand the suite of available lithologies and compositions, while also try to address limitations of previous simulants.Extensive research has been conducted by our team to analyze the chemical and physical properties of martian surface datasets, including their mineralogy, grain size distribution, and chemical composition. [2], [5], [6]. Thus, our new Martian simulants have been developed to better represent the unique geological and mineralogical features of specific locations of the martian surface. We have used XRD, SEM-EDS, and LIBS analysis to verify the accuracy of our simulants to the reference target compositions. The additions of those new simulants, and their characterisation steps, provide valuable insights for developing even more accurate simulants of the varied geological and environmental conditions of current and early Mars.Our approach to simulant fidelity and quality involves firstly the reproduction of the accurate mineralogy, which can finally be expressed in chemical terms using an arithmetic quality value, the Figure of Merit (FoM) [3],[4]. This is a standardized fidelity compositional comparison of the oxide differences with the compositions of the reference datasets. In this FoM the grain size distribution and other parameters are not included. The same FoM system is also used to compare our different simulant batches in order to ensure consistency in their production. A constant increase in FoM is achieved in each consequent batch of simulants produced in our lab, with values exceeding 90% of FoM. These values provide confidence in our methods since it provides a way to increase the fidelity of the simulants.In this presentation we will discuss the methodology and tools we use to achieve the above results, aiming to more representative lithologies, compositions and textures. For each new simulant, we also address the potential impact on specific fields of research, such as their compatibility for either ISRU research, or for astrobiological investigations. We envisage that with further research we can cover the requirements for simulants of new research studies, addressing topics such as planetary evolution and habitability.1. G. H. Peters et al. (2008), Icarus 197, 470-479.2. H.-A. Stavrakakis et al. (2022), EPSC2022.3. C. Schrader et al. (2009), 47th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition, p 755.4. L. E. Fackrell, et al. (2021). Icarus 354, 114055. 5. D. Argyrou et al. (2023), EANA23. “Characteristics of Greek Martian and Lunar Simulants: Insights from the initial development”6. Georgiou C. et al. (2023), EANA23. “OxR: A novel device for Reactive Oxygen Species (ROS) detection for astrobiology and planetary research”

Introduction: Astrobiology Graduates in Europe (AbGradE, pronounced ab-grad-ee) is an association of early-career scientists working in fields relevant to astrobiological research. Conceptualized in 2013, it was initially designed as a mini-conference dedicated to early-career researchers (ECAs) in a more relaxed environment than that of traditional conferences. Our meetings act as a networking opportunity, as well as a practice round and steppingstone for ECAs entering the world of academic research.Audience & topics engaged: Our audience is mostly composed of graduate students and post-doctoral fellows, but not only: undergraduates, senior scientists, and researchers from different disciplines with a strong interest in astrobiology are also welcome to attend our meetings. The topics engaged at our events, both symposia and workshops, naturally include the obvious themes related to astrobiology, and go beyond them by delving into social sciences and humanities (e.g., an online Space law and governance meeting in 2021). Specific workshops were organized on more practical issues like science communication, space mission design, networking, and navigating post-graduate research. Other issues, like mental health in a research context, are also considered for future editions.Collaborations: AbGradE has been involved in astrobiology schools, such as the EANA International hydrothermal spring school. As the spiritual daughter organization of EANA, AbGradE maintains strong ties with it while developing on its own into an organization by ECAs, for ECAs, in a similar fashion to how AbGradCon operates. Over the years, AbGradE also teamed up with other organizations, like the European Astrobiology Campus (EAC), the European Astrobiology Institute (EAI), and the Europlanet Early Career (EPEC) Network.Online presence: In the spirit of the “work from home” attitude prevalent during the COVID-19 pandemic, AbGradE has attempted to provide more online resources. Apart from moving meetings online, we have built a website and sent out a quarterly newsletter to keep ECAs engaged, and to encourage a sense of community during the lockdown-ridden time of the pandemic.Scope: Within the last couple of years, AbGradE became the first point of call for European, but also for an increasing number of non-European ECAs, especially with the recent development of online resources. This presentation aims to present how AbGradE has evolved over the years (in its structure and in its way of organizing events), how it has adapted with the COVID-19 pandemic, and what future developments are considered.

Introduction:The interest for the Moon has risen with many missions being planned for the Moon surface culminating to the Artemis missions, spearheading a new era of human presence on the lunar surface. At the same time a recent paper (1) provided an overview of the current state of Martian research and understanding. A common theme on both of these endeavors is the requirement of extensive research across the fields of astrobiology, the frontier of ISRU technologies and habitability research under simulated conditions of those environments. A large number of Lunar and Martian Simulants has been developed over the past decades, often though produced rapidly with lower fidelity to satisfy demand  (2). Towards this purpose, our group made an effort to develop such materials, since in Greece only potentially analogue locations for simulated research exists. This research was initiated with the introduction of a new simulant classification system, after having highlighted a number of issues that pertain on the facet of Martian Simulants. We here report on the development of new simulants we produced for the Lunar and Martian surfaces.Methodology:Initially, we scrutinised the literature focusing on three focal points of research to collect data on the composition of Lunar and Martian surface location, the Lunar Curator Facility, the Analyst’s Notebook and the respective publications on simulant production, in order to identify which datasets have been already utilised. Based on these data, we selected one Lunar and two Martian locations to produce simulants. For the Moon we selected the 15260 Apollo Sample which has been extensively studied. (3) For Mars, we opted for the Rocknest and Gobabeb targets, which are 2 of the most cited and compared sites for simulant production. More specifically, for Moon we utilised the chemical analysis provided by (3) and for Mars those provided by (4).For the simulant development we collected a number of igneous rock samples from the field, and acquire a number of pure mineral phases, for use as individual components, presented in table 1. All of the materials utilised by our team in the synthesis of the simulants have been firstly crushed and grounded to a grain fraction of under 1 mm. A portion of the material was further crushed in under 250 μm, and later refined for XRD analysis. Each sample was then scanned in three random locations via SEM-EDS and the average analysis was taken as the sample’s chemistry. Thus, via those two analytical techniques, the background of the chemical and mineralogical make up of our inventory of materials was established.In order to establish the quality of our simulants we utilised the Figure of Merit (FOM) proposed by (5) and applied by (6). By using this system you can deduce the accuracy of your simulant based on how close the percentages of chemical oxides are to the reference sample.Simulants:Up to the point of writing, our team has produced a total of four simulants, two for the Moon and two for Mars. Initially a production of two prototypes for a Lunar and Martian simulant, Simulant #1 and #2 respectively, were made by mixing three individual mineral and rock components to verify the method of synthesis and correct any mistakes. However, even at that stage the theoretical FOM of our Simulant #1 was above 95% when compared to the Apollo 15260 sample, and Simulant #2 for Mars had FOM 90,7% and 89% for the Rocknest and Gobabeb targets respectively. (Table 1) Based on the preliminary results we produced refined simulants, Simulant #3 and #4 for Moon and Mars respectively, using additional components materials as showed in table 1. Thus, Simulant #3 for the Apollo 15260 sample reached FOM of almost 96% and Simulant #4 for Mars reached FOM of 94,6% and 91,6% for the Rocknest and Gobabeb targets, respectively. (Table 1) Future Goals:The goal of this project is to try and make simulant materials for Moon and Mars more accessible to the scientific community, but also provide materials of higher fidelity and accuracy. Based on their chemistry, the FOM values on the martian simulants are higher than those presented in (6), suggesting that our endeavor has significant prospects compared with the fidelity of other simulants and providing the confidence that higher accuracy simulants can be synthesised. Furthermore, an additional number of analytical techniques will be used to verify their fidelity. Additionally, by the acquisition of additional mineral phases and rock samples we are targeting to increasing the FOM values. A short term requirement is also the availability of well-known simulants in order to be used in the OxR ESA project (7).References:H. G. Changela et al., Mars: new insights and unresolved questions. International Journal of Astrobiology, 1-33 (2021). G. H. Peters et al., Mojave Mars simulant—Characterization of a new geologic Mars analog. Icarus 197, 470-479 (2008). A. Duncan et al. (1975) Interpretation of the compositional variability of Apollo 15 soils. in Lunar and Planetary Science Conference Proceedings, pp 2309-2320. C. Achilles et al., Mineralogy of an active eolian sediment from the Namib dune, Gale crater, Mars. Journal of Geophysical Research: Planets 122, 2344-2361 (2017). C. Schrader et al. (2009) Lunar regolith characterization for simulant design and evaluation using figure of merit algorithms. in 47th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition, p 755. L. E. Fackrell, P. A. Schroeder, A. Thompson, K. Stockstill-Cahill, C. A. Hibbitts, Development of Martian regolith and bedrock simulants: Potential and limitations of Martian regolith as an in-situ resource. Icarus 354, 114055 (2021). ESA (2022) https://www.esa.int/Enabling_Support/Space_Engineering_Technology/Moon_and_Mars_superoxides_for_oxygen_farming. Table 1. Simulant components and Figure of Merit percentages.

Since the 90s, an ever-increasing number of missions to Mars have been conducted which offer a plethora of information about the red planet. This information also led to the rapid development and advancement of prominent scientific fields in space and planetary exploration, such as astrobiology and ISRU technologies. The experimentation and research requirements of those fields, as well as, the need for better vehicle and instrument testing for further development, so that they will better operate on Martian conditions and its surface, increase in significance. Currently, this is performed with the use of natural (Analogue) and synthetic (Simulant) Geomaterials. However, the accessibility and the analysis of analogue and simulant data requires a thorough literature review in order to  identify implications for future research. In our latest research work, we conducted this detailed review and we identified, grouped, and analysed a number of implications that pertain mostly to the synthesis procedures of simulants, but also extend to the in situ analytical data from Mars that are used as a reference. Furthermore, we identified an urgent need for improving the current state of simulant research, as it is currently very time consuming and has implications, in hope that systematic work on the topic will culminate in a general standardisation effort.The current work was done by analysing data on all available simulant geomaterials in order to provide recommendations and suggestions for mitigation actions for their development and their use during research, as well as to advocate the needs for a unified standardisation system. These actions include: (a) the consolidation of existing literature into database formats with easy access, based on (b) the development of a new informational construct based on ontologies and semantics, (c) to propose a classification system for simulants that is missing from the literature, and (d) assist the simulant geomaterial selection process through a proposed step algorithm. The ontological and semantic mindset should be followed at every step, and it is incorporated into the classification system, thus enabling easy access and interpretation by both humans and machines. This set of tools and recommendations should be applicable on all simulant related facets of space exploration. 

Astrobiology Graduates in Europe (AbGradE, pronounced ab-grad-ee) is an association of early-career scientists working in fields relevant to astrobiological research. Conceptualized in 2013, it was initially designed as a mini-conference or workshop dedicated to early-career researchers, providing a friendly environment where early-career minds would be able to present their research without being intimidated by the possibility of facing a more traditional audience, composed mainly of senior scientists. Within the last couple of years, AbGradE became the first point of call for European, but also for an increasing number of non-European, early-career astrobiologists. This article aims to present how AbGradE has evolved over the years (in its structure and in its way of organizing events), how it has adapted with the COVID-19 pandemic, and what future developments are considered.

Mars exploration motivates the search for extraterrestrial life, the development of space technologies, and the design of human missions and habitations. Here, we seek new insights and pose unresolved questions relating to the natural history of Mars, habitability, robotic and human exploration, planetary protection, and the impacts on human society. Key observations and findings include: –high escape rates of early Mars' atmosphere, including loss of water, impact present-day habitability; –putative fossils on Mars will likely be ambiguous biomarkers for life; –microbial contamination resulting from human habitation is unavoidable; and –based on Mars' current planetary protection category, robotic payload(s) should characterize the local martian environment for any life-forms prior to human habitation. Some of the outstanding questions are: –which interpretation of the hemispheric dichotomy of the planet is correct; –to what degree did deep-penetrating faults transport subsurface liquids to Mars' surface; –in what abundance are carbonates formed by atmospheric processes; –what properties of martian meteorites could be used to constrain their source locations; –the origin(s) of organic macromolecules; –was/is Mars inhabited; –how can missions designed to uncover microbial activity in the subsurface eliminate potential false positives caused by microbial contaminants from Earth; –how can we ensure that humans and microbes form a stable and benign biosphere; and –should humans relate to putative extraterrestrial life from a biocentric viewpoint (preservation of all biology), or anthropocentric viewpoint of expanding habitation of space? Studies of Mars' evolution can shed light on the habitability of extrasolar planets. In addition, Mars exploration can drive future policy developments and confirm (or put into question) the feasibility and/or extent of human habitability of space.