Workshop opening and introduction (Moving to Mars Workshop: 17-18 November) Room: Rooms A&B

Keynote speech #1 - Opportunities and Challenges of Human Space Exploration: Moon or Mars? The key role of aerothermodynamics for the next steps (Moving to Mars Workshop: 17-18 November)

• ESA Astronaut Roberto Vittori

Room: Rooms A&B

Keynote speech #2 - Propulsion, Aerothermodynamics and Flight Vehicles Technology Development for Mars applications (virtual) (Moving to Mars Workshop: 17-18 November)

• Jamila Mansouri (Head of the Propulsion and Aerothermodynamics Division (ESA/ESTEC))

Room: Rooms A&B Head of TEC-MP Division

Plenary Round Table: Human Missions to Mars; technological challenges, new strategies, solutions and risk mitigation (Moving to Mars Workshop: 17-18 November)

• Nicole Viola (Politecnico Di Torino)

Room: Rooms A&B

Miniature Planetary In-situ Sensors (MiniPINS) - MINS lander (Moving to Mars Workshop: 17-18 November)

• Maria Genzer (Finnish Meteorological Institute)

Room: Rooms A&B MiniPINS is an ESA funded study led by the Finnish Meteorological Institute to develop and prototype miniaturised surface sensor packages and their delivery systems for Mars (MINS) and the Moon (LINS). The study aims at miniaturizing 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 study covers mission development phases 0 - B1, and has delivered its results in the Final presentation at ESTEC in October 2022. This presentation concentrates on MINS (Mars In-situ Sensors) surface sensor package and its delivery system. MINS is a penetrator with approximately 25 kg mass, piggy-backed by another Mars mission spacecraft to Mars and deployed either from the approach orbit or Mars orbit. In MiniPINS mission, 4 penetrators are planned to be released to different landing sites on Mars. The design of MINS has significant heritage from FMI’s MetNet mission design [1], with some changes introduced after recent modelling efforts. In the Martian atmosphere the penetrators perform autonomous aerodynamic braking with inflatable braking units (IBUs) until they reach the target velocity of 60-80 m/s for entering the Martian surface. The penetration depth target is up to 0.5 m, depending on the hardness of the soil. The geometry of MINS penetrator includes a thin section to improve penetrability to the soil, a medium section with 150 mm diameter to accommodate a 2U CubeSat structure inside, and a top section with a wider diameter to stop the penetration and avoid the top part to be buried inside the soil. The deployable boom is accommodated in the top section along with the surface sensors. MINS penetrator carries sensors to perform an ambitious science program to study the Martian atmosphere, seismology, and soil chemistry. Scientific measurements will be performed above, at and below the Martian surface. MINS nominal mission is designed to last for 1 Martian year (2 Earth years) with another Martian year as an option. The small size of MINS makes it a good candidate for forming a large observation network on Mars. Power production of the nominal MINS design is based on solar panels, which restricts the possible landing sites below +/-40 degree latitudes, but for polar missions the design could be altered to utilise also an RHU, which would provide enough thermal energy for MINS to survive and operate also during the Martian winter. [1] Harri et al. (2017), The MetNet vehicle: a lander to deploy environmental stations for local and global investigations on Mars, Geosci. Instrum. Method. Data Syst., 6, 103-124

Thermal Analyses and Tests of the ExoMars Rover Locomotion System (Moving to Mars Workshop: 17-18 November)

• Jean-Francois Labrecque (MayaHTT)
• Charles Villemure (MDA)

Room: Rooms A&B Led by the European Space Agency, the ExoMars mission will address the question of whether life has ever existed on Mars. The first part of the mission, the Trace Gas Orbiter, was launched in 2016. The second part, the Rosalind Franklin rover, will be Europe’s first rover on the surface of Mars. Its objective is to travel on the surface, collecting underground samples and analyzing them on a next-generation on-board laboratory. MDA contributed to the mission by providing the locomotion sub-system, dubbed the Bogie Electro-Mechanical Assembly. BEMA includes all the components required for on-surface locomotion, and comprises the pivoting structure, legs, 6 flexible wheels as well as 18 rotary actuators that will enable all roving operations on the surface. The environment on the Mars surface is unique, and predicting the thermal performance poses a real challenge. With an atmosphere approximately 170 times less dense than Earth and consisting mostly of Carbon Dioxide (CO2), temperatures oscillating between -140°C and 25°C, in addition to the occasional dust storms, there are few software tools which are able to reproduce the thermal environment in its entirety. To predict the performance, MDA used SimCenter3D (SC3D). SC3D’s Space System Thermal module has been used for thermal analyses in the space environment for over 30 years, but the software also has complete CAD/CAE integration and full CFD capabilities. That allows modeling the radiation-driven space environment, but also the detailed fluid volume and convective heat exchanges to any level of detail. Using this software, the thermal design of the locomotion system could be established in order to maximize the operating time of the rover during the Martian day, with an effective heat-up in the morning, high heat rejection capabilities to increase roving time, as well as minimal heat losses overnight. The components and final assembly were tested to simulate exposure to the Martian environment. Testing itself had a lot of challenges, as fully representing the Mars environment is not feasible with standard testing facilities. To be able to do that, MDA repurposed one of its thermal vacuum chambers to maintain a partial vacuum and a CO2 atmosphere. With this adapted test facility, MDA was able to perform life tests and fully qualify the assembly for its upcoming mission on Mars.

Laser Thermal Propulsion for 6-Month Round-Trip Missions to Mars (Moving to Mars Workshop: 17-18 November)

• Emmanuel Duplay (TU/Delft)
• Andrew Higgins (McGill University)

Room: Rooms A&B Background of the study The potential for laser-thermal propulsion has recently been proposed to realize near-term rapid transit to Mars missions (Duplay et al., Acta Astro., 2022, DOI: 10.1016/j.actaastro.2021.11.032). The ability to reach Mars in 45 days would largely eliminate the long-term risk from GCR exposure and greatly facilitate human exploration and potential settlement of Mars. A rapid return mission is more challenging, since laser thermal propulsion requires a large, high-power (GW-class) laser at the location of the impulsive maneuver. Traditionally, it has been assumed that a directed-energy infrastructure for solar system transportation would have to await industrialization of the other planets. In this talk, we will explore concepts that would enable laser thermal propulsion to be used on both ends of a humans-to-Mars mission in the near term, possibly even immediately following the first few crewed Martian missions. Methodology Astrodynamics solutions done through patched conics and Lambert’s algorithm confirm the viability of a six-month round-trip mission to Mars, consisting of a two-month outbound flight, a one-month stay at Mars and a three-month return to Earth. The one-month surface stay could alternatively be swapped out for a synodic period surface stay (2.1 years). These solutions do not require a delta-V beyond the expected capabilities of a laser-thermal system. A summary of ongoing experimental work at McGill University to support theoretical predictions for the performance of laser-thermal propulsion is provided, with expected testing of a laboratory-scale, 3-kW-class prototype thruster to commence in 2023. The potential of transporting a GW-class laser array to Mars and then powering it via in-situ resource utilization is examined. Results The energy that would need to be produced on Mars to power the laser-thermal burn back to Earth is found to be feasibly provided via solar photovoltaics, leaving energy storage and power delivery as the main challenge. Several options are explored, including lithium-ion battery storage, chemical energy storage in propellant form to be released on demand, and other in-situ options. The notional capability of the proposed SpaceX Starship vehicle is used as the baseline for the infrastructure that will be available. A tentative solution that could be enabled with a small number of missions would be to use MHD power generation via the exhaust of a Starship Raptor engine fueled by in-situ propellant production. Conclusion The early deployment of robust infrastructure that can safely and quickly deliver humans to and from Mars would greatly increase the attractiveness and of realizing long-term Mars settlement in the coming decades.

Round Trip Mars Mission Architecture with 6-month Duration via Propellantless Plasma Surfing (Moving to Mars Workshop: 17-18 November)

• Mathias Larrouturou (McGill University)

Room: Rooms A&B Background of the study The possibility of a 6-month round-trip mission to Mars using a propellantless propulsion system termed *plasma surfing* is investigated. The technique is based on the idea that a spacecraft interacting electromagnetically with the solar wind can generate a lifting force perpendicular to the apparent direction of the wind. The lift-generating mechanism extracts power from the flow over the vehicle in the apparent wind direction, which is then used to accelerate the surrounding medium in the transverse direction, generating lift at the expense of drag. The proposed implementation uses two plasma magnets to stroke the solar wind, extracting power in the process, while acceleration of the surrounding medium is achieved by launching plasma waves propagating at low group velocity. The concept for extraction of power from the solar wind via plasma magnets was previously established by Greason (*JBIS*, 2019), and the use of the extracted power to launch transverse plasma waves for lift was developed by Larrouturou et al. (*Frontiers in Space Technologies*, under review). In this presentation, we will apply this technology to realizing a rapid-transit, round-trip mission architecture for human exploration of Mars. Methodology In the trajectories investigated here, the lift generated is used to gain or lose orbital velocity to transfer from one orbit to the other. The simulations are done via numerical integration in a simplified planar, circular concentric model of the sun-Earth-Mars system. Transferring from Earth orbit to Mars orbit can be achieved relatively easily by first increasing orbital velocity to overtake Mars, and second losing excess velocity to rendezvous. The return transit (Mars to Earth) is more challenging, since it is problematic for the spacecraft to sail upwind. Therefore, for the return trip the spacecraft has to lose orbital velocity by directing the lift vector against the orbital direction (canceling orbital velocity) and then switch off the plasma interaction to accelerate toward the Sun under gravitational attraction alone. Once the Earth has been passed, the plasma interaction is turned back on and the spacecraft’s orbital velocity increases and turns to match Earth’s velocity. The lifting flight trajectory is optimized numerically to identify launch windows and to maximize duration on the Martian surface. Results In the numerical trajectory simulations incorporating orbital mechanics and plasma interactions, the ability to transfer from one orbit to another without the use of propellant has been demonstrated. The ability to use plasma surfing for round trip transits to and from Mars with a total trip time of six months is seen to be feasible, minimizing the risk to the crew posed by galactic cosmic rays and coronal mass ejection events. Conclusion The ability to perform a round-trip Mars mission of the same duration and radiation exposure of a typical ISS stay would greatly enable human exploration of Mars. The fact that the system is ideally propellantless provides the possibility for an economical, scalable, and robust infrastructure for interplanetary transportation.

Narrow Angle Camera for the MSR-ERO Mission (Moving to Mars Workshop: 17-18 November)

• Emmanuelle Harel (sodern)

Room: Rooms A&B Beginning of 2021, Sodern has been selected by Airbus Defence and Space for supplying the Narrow Angle Camera (NAC) in the frame of the Mars Sample Return spacecraft a key element of the Earth Return Orbiter (MSR-ERO) mission. The Narrow Angle Camera is meant to take images of the Orbiting Sample (OS) and stars in the vicinity of mars, in both for OS detection and the orbit determination and during the Rendezvous (RDV) phase of the MSR-ERO mission. Sodern uses its expertise built up over decades in star trackers and cameras development, in particular with the recent development of the navigation camera (NAVCAM) for the Jupiter Icy Moon explorer (Juice) ESA mission. This paper describes the current features of the NAC camera and the ongoing activities.

Advanced hybrid sensing system for prospecting on the Moon and Mars (Moving to Mars Workshop: 17-18 November)

• Richard Boudreault (École Polytechnique)

Room: Rooms A&B Mankind has been exploring the Moon and Mars for decades, but our knowledge is being held back by scientific instruments that are unable to collect high-resolution data about a planet’s subsurface composition. The available technologies reveal only partial information about the elemental subsurface composition of planetary bodies; preventing important discoveries of water ice, mineral deposits, caverns, or liquid brine deposits that might be leading indicators of extraterrestrial life. The Canadian Space Mining Corporation (CSMC) is developing a geophysical prospecting and 3D imaging instrument called Temporal and Impedance Prospecting Sensor (TIPS), which advances the state-of-the-art in planetary exploration. TIPS is a novel design that combines measurements of ultrasound and electrical impedance interacting within the Time-Domain to generate non-invasive tomography. TIPS will be deployed from on-board a mobile platform such as a rover, from which electrodes will contact the surface, measure the behavior of the materials to an impedance current and ultrasonic perturbation, and process the data to deliver 3D tomography of a specific region that can be reconstructed in real-time. The concept of measuring impedance and ultrasound vibrations for imaging is not new, but 3-dimensional imaging using the time-domain signal that segments and filters the data and delimits the elemental composition is an entirely new capability. TIPS has transformational implications for both scientific and commercial activities in space. Localizing sources of water, for example, is mission-critical for life-support and enabling in-situ resource utilization (ISRU) on the Moon, Mars, and beyond. On the Moon, there are hints of water ice in the low latitudes and more permafrost buried in the regolith near the equator, but strong indications are present in the permanently shadowed craters of the poles. The same is likely true for traces of liquid water on Mars. The electric and sonic response of water is distinct compared to dryer regolith. It is feasible to detect water in a column of about 20 meters in depth with a centimeter resolution. The existence of liquid water at these depths leads to identifying the presence and composition of brines, thereby eliminating wasteful excavations that yield no value or identifying ideal Martian conditions for microbial life that may yield generational advancements in the field of astrobiology. Localizing mineral deposits is another critical application of TIPS, which is able to delimit hydrated sulfates, hematites, and perchlorates. Geotechnical characterization of the subsurface based on the density profile and presence of lava tubes is yet another. In sum, TIPS is an advance to the state-of-the-art for planetary and resource exploration methods. It provides mission-critical knowledge of the local evolution of geology and of hydrogeology. CSMC expects TIPS to initially support preliminary surveys for sample return missions and deliver more data to determine appropriate landing, settlement, and resource extraction sites on the Moon and Mars. It significantly reduces the overall mission cost while increasing the probability of generational discoveries and mission success.

Feasibility of vehicle-based propellant production on Mars using the Sabatier reaction (Moving to Mars Workshop: 17-18 November)

• Francis Desilets-Mayer

Room: Rooms A&B The Martian atmosphere is one of the easiest resources to access on the red planet. This makes it a prime candidate for in-situ resource utilization (ISRU). As a result, a handful of proposed architectures for manned mission to Mars have included the following ISRU scheme: the CO2 rich air, in conjunction with ice deposits, is reacted into methane and oxygen using the Sabatier reaction. As a rocket propellant, the mixture of methane and oxygen, also called Methalox, is much easier to store and less corrosive than hydrogen-based alternatives. Most notably, Elon Musk, the CEO of SpaceX, unveiled in 2016 a manned mission architecture that included ISRU for Methalox production on Mars. In this plan, one of SpaceX’s rockets, the so-called Starship, would be refueled on Mars during a single synodic period. To evaluate the feasibility of a Methalox production plant on Mars, our team devised a process flow simulation in DWSIM and used it to evaluate the size of the equipment necessary. The production target for the simulated plant was 325 kg/day of liquefied methane and 1385 kg/day of liquified oxygen, enough to refuel SpaceX’s Starship over the span of 26 months with a 3.66 fuel ratio. The design of the simulated plant drew its inspiration from the many proposals for Methalox production plant published in the literature, mainly those involving the Sabatier reaction. The choice of equipment was made in accordance with best practices in the chemical industry. The plant design included a cryogenic atmosphere capture unit, a polymer electrolyte membrane electrolyzer, a Sabatier reactor, two membrane separators, two consecutive gas cleaning units, and a cascading liquefaction unit. Ice refining operations, as well as electricity production and propellant storage, were outside of the scope of our analysis According to our simulation, this Methalox plant would consume a continuous 573 kW of electricity and have a volume of 41 m3. Overall, the electrolyzer consumed the most electricity and the Sabatier reactor occupied the most space. The biggest source of uncertainty in our simulation comes from the gas treatment unit and cooling unit which were modeled using extrapolations of correlations. This is especially true for the gas unit destined to scrub water and CO2 from the oxygen stream. In all cases, our designed Methalox plant would fit within the 1000 m3 cargo space of SpaceX’s Starship. This does not contradict other published estimations. The current design of the plant can however be improved, especially on the level of equipment choice. From a chemical engineering standpoint, this is a miniature chemical plant. At this scale, electrochemical reactors, thermoelectric cryocoolers, and molecular sieves could be more advantageous than the equipment we chose for our analysis.

Design of a Mars Transit Vehicle for human space missions in 2040: an International Master SEEDS project work (Moving to Mars Workshop: 17-18 November)

• Antonio Rotondi (Politecnico di Torino)
• RIccardo Moro (Politecnico di Torino)

Room: Rooms A&B Reaching Mars is the next giant leap for humankind in the exploration of the Solar System and transporting a crew safely from Earth to the Red Planet is arguably the most challenging aspect of this expedition. This work presents the project carried out during the XIV edition of the Master SEEDS – Space Exploration and Development Systems, which gathered 35 students from Politecnico di Torino, Italy, ISAE-SUPAERO Toulouse, France, and University of Leicester, UK, to tackle the problem in collaboration with Thales Alenia Space, Altec and the Italian Space Agency. The constraints of the mission of MaVeRiC – Mars Vehicle foR Interplanetary Cruise are a mission duration of roughly 1000 days in the timeframe between 2030 and 2040 and the capability of supporting a crew of four astronauts. After deriving the mission objectives and the high-level requirements, a preliminary design study has been performed and different solutions were assessed and compared. In the end the final configuration has been defined and is presented here. The result is a vehicle composed of two habitable modules that contain all the life support systems and payload for the execution of scientific experiments during the travel. Moreover, they comprise the adequate living spaces for the crew, a greenhouse to produce fresh food and all the physical exercise equipment, including a short arm centrifuge combined with a cycle ergometer for the counteraction against the microgravity effects on the human physique, given the necessity for the astronauts to be fit and autonomous at the arrival on Mars. An additional cargo module is attached to provide all the necessary consumables and increase the habitable volume. Regarding the other subsystems, the spacecraft is equipped with a nuclear propulsion system employing liquid hydrogen, that is stored in discardable tanks to improve the efficiency of the maneuvers. The three reactors composing this system are also connected to two Brayton cycle engines to produce electric power. The tanks, habitable modules and propulsion and power systems are linked via a truss structure, where also the other subsystems are located. The radiation protection of the astronauts is achieved via multiple methods, comprising the use of a shield of hydrogenated boron nitride nanotubes and the exploitation of the on-board water and waste, through a heat melt compactor. All the modules are going to be assembled in the lunar orbit with multiple launches and using space tugs and the spacecraft can be reused for multiple Mars transfers. During this project, a complete design of a human Mars transfer vehicle has been developed and different problems studied: all the feasible solutions have been included in the final design, tackling issues related to the microgravity environment, the radiation protection and the long duration of the mission. Then, a risk, programmatic and cost analysis have been performed to allow the possibility to propose this concept to the international space community, while also highlighting the main critical technologies whose development should be pursued by the space agencies.

A Bioinspired Vibro-Based Robotic System for Space Mining

• Pooneh Maghoul (École Polytechnique)

Room: Rooms A&B Due to payload limitations in space missions, light and compact investigation tools should be developed for subsurface exploration on the Moon, Mars, and beyond. In this talk, I will present our Bio-Inspired Vibro-Based Burrowing Probe (BVBP) prototype, which is designed to mimic the ‘squirming’ locomotion of snakes in granular soils (e.g. sand beach) for space mining. Our innovative robotic employs a lateral vibration mechanism by using piezoelectric driving units. The vibration motion can cause loss between contact parts, such as a probe in the soil, and hence can reduce the friction between the probe and soil and make the penetration easier.

Day #1 wrap-up (Moving to Mars Workshop: 17-18 November) Room: Rooms A&B

Day #2 - Introduction (Moving to Mars Workshop: 17-18 November) Room: Rooms A&B

Keynote speech #4 - An ESA Perspective on Future Mars Surface Platforms for Terrae Novae Programme 2030+ (virtual) (Moving to Mars Workshop: 17-18 November)

• Andrew Ball (Exploration Preparation, Research and Technology (ExPeRT) Team (HRE-E) - ESA/ESTEC)

Room: Rooms A&B

DROP THE BASE: Biological, ISRU-Based Aleatory Construction System for Martian Habitats (virtual) (Moving to Mars Workshop: 17-18 November)

• Monika Brandic Lipinska (Hub for Biotechnology in the Built Environment)

Room: Rooms A&B Building on Mars brings challenges observed from two angles. The constraints associated with the distance from Earth and the Sun, are the lack of construction materials and machinery, the complexity of the process with communication delays, and the energy attainability. Therewithal, there are challenges associated with environmental conditions like different gravity conditions, lack of a breathable atmosphere, and need for protection from radiation. Such extreme conditions, where resources are highly constrained, call for a reinvented construction process, developed specifically for these conditions. One of the alternative approaches for extraterrestrial construction is the use of biological materials. Such materials could be brought from Earth, and replicated in situ, for the construction of surface habitats and other structures. We are proposing the biofabrication strategy for stabilizing regolith using mycelium. This approach focuses specifically on building in resource-limited conditions. It considers the biomass, water, and oxygen use when it comes to creating the structural components, and the assembly process when it comes to the energy use and a need for robotic operations. The work proposes the creation of in situ grown regolith-based biocomposites. However, instead of creating bricks that would require an additional assembly process, the elements would act as “construction seeds”. The components could be literally dropped (due to lower gravity eliminating the risk of crushing) and aleatorily assembled, within the guiding framework. The stacked elements would create a bio-aggregate system, which due to the living matter, could perform biowelding; grow together, and turn into a solid structure, creating a protective habitat shell. The work demonstrates mycelium growth in inorganic soils, its binding properties, and the structural interaction between mycelium, biomass, and soil. It also presents the early developments toward a bio-aggregate system that would work in reduced gravity conditions, enabling the construction of extraterrestrial habitats with minimal energy and additional resources. It addresses the challenges for biological fabrication for building on Mars, including understanding the complexity of biological material synthesis, the predictability and precision of the result, and the scale-up of processes.

2D dynamic interaction of semi-circular Martian habitat and its shielding system (Moving to Mars Workshop: 17-18 November)

• Hamed Seifamiri (Polytechnique Montréal)

Room: Rooms A&B It is approaching 50 years since the last human walked on another planetary body (Apollo 17, 1972). The launch of the Insight mission to Mars and the Artemis mission’s human return to the moon presents a unique opportunity for human settlement on Mars and the Moon. To ensure a successful human settlement on Mars and Moon at scales beyond the traditional reconnaissance and exploratory missions, we need to address a host of challenges at multiple levels. Some key examples of these challenges are in-situ harvesting of energy, water, and oxygen, as well as a scarcity of material resources for sustainable construction. Hence, novel construction paradigms must be developed by applying the practice commonly known as In-Situ Resource Utilization (ISRU). Furthermore, the design of structures such as shelters to shield astronauts and materials from the hostile environment on Mars and the Moon require specific considerations including seismic sources like meteorite impacts, low gravity, thin atmospheres, and abrupt surface temperature variations. We must select a different strategy and carefully consider each of the aforementioned factors in the design and construction. In the literature, a variety of conceptual structures for the lunar and Martian surfaces have been proposed, including deployable, 3D-printed, and generic structures. Additionally, it has recently become a popular idea to use the lunar or Martian lava tubes as a shelter. In this paper, the dynamic behavior of various regolith shelters on the Martian semi-circular structure is studied. We have simulated a number of models under synthetic Marsquake signals in order to evaluate the key characteristics of the seismic response of various covering systems. The numerical program SiteQuake (Finite Element (FE)/Boundary Element (BE)) is used for this purpose. We look into the primary structure's spectrum amplification under vertical in-plane signals. The extraterrestrial structures and their shield systems are simulated using the FE, while the bedrock and half-space conditions are simulated using the BE, which assures that there are no reflecting waves from the boundaries. One-tenth of the wavelength is chosen as the mesh size for the elements. The seismic signals are imposed as displacement time histories in the BEM section. The results show the intricate nature and complex dynamic interaction of the structure and covering systems due to the scattering of waves in different parts of the structure’s body. Our findings imply that the coupling of these Martian structures and their covering systems must be considered simultaneously in the design in order to accurately reflect the seismic interaction between them. These preliminary findings are based on a conceptual design. Detailed models are required for real-world scenarios.

Deimos Space and Mars: a European history (virtual)

• Federico Trovarelli (Delft University of Technology)

Room: Rooms A&B

A Deep Learning Method for the Dispersion Relation Prediction of Rayleigh Waves and Shear Wave Velocity Inversion (Moving to Mars Workshop: 17-18 November)

• Shihao Cui (Polytechnique Montreal)

Room: Rooms A&B This paper proposes a deep learning model for the dispersion relation prediction of Rayleigh waves and shear wave velocity inversion. The proposed deep learning method includes the forward model and the inversion model. The forward model is built by the convolution neural networks, which are used to predict the dispersion relation by the shear wave velocity; the inversion model is designed by the transformer to inversely estimate the shear wave velocity in the subsurface layers. The synthetic data generated by a constrained Markov decision process and the fast vector transfer method are used for model training and testing. 90,000 and 10,000 samples are used for the training and testing of the model, respectively. Rayleigh waves have been widely used for subsurface investigation because of their intense energy and slight attenuation. Traditionally, the process of subsurface investigation based on Rayleigh waves can be divided into three steps. The first step is dispersion relation extraction. Different methods can be used to extract the dispersion relation from the experimental data through the multi-channel analysis of surface waves (MASW) or the spectral analysis of surface waves (SASW). The MASW requires a series of geophones placed on the ground surface, while the SASW only needs two geophones. The second step is the forward model building to determine the theoretical dispersion relation. Various methods for the forward model have been developed such as the Haskell-Thomson method, the delta matrix method, the Schwac-Knopoff method, the fast vector transfer method, the spectral element method and so on. The third step is the inversion process based on the extracted experimental dispersion relation and the generated dispersion relation by the forward model. The disadvantage of the traditional method includes: first, the forward model is not always stable to develop the theoretical dispersion relation; when the dispersion relation curve is complex, the root-searching process may not find a good solution. This may bring uncertainties in the inversion process during the variable updating. Second, convergence cannot be guaranteed in the inversion process because the inversion process for the subsurface characterization is an ill-conditioned non-linear problem, and it is easy to trap into the local optimization. The third disadvantage is the initial value for the inversion process is important; this requires prior knowledge. With the development of artificial intelligence, machine learning techniques unfold opportunities to handle dispersion relation determination and subsurface characterization. In particular, the deep learning method aims to use various kinds of neural networks to map the complex non-linear relationship between the input and the output. An example of such a complex non-linear problem is the forward model and the inversion process for the subsurface characterization based on the dispersion relation of Rayleigh waves. There are different deep learning models such as fully connected neural networks (FCNNs), convolution neural networks (CNNs), recurrent neural networks (RNNs), transformers, and so on. Therefore, a deep learning-based method is proposed for both the forward model and the inversion process in this work.

Rapid prototyping for Martian space systems (Moving to Mars Workshop: 17-18 November)

• Giuseppe Governale

Room: Rooms A&B With the clear path towards Mars for future human exploration missions, rapid prototyping tools may enhance different missions' architectural solutions. Such tools rapidly estimate mass, power and data budgets, providing quantitative figures of metrics to evaluate the most effective technical solutions in line with the stakeholders' needs. Politecnico di Torino is actively working on IDREAM an integrated framework with capabilities of sizing space systems, estimating their cost and building roadmaps for the maturation of the involved technologies. The iDREAM methodology consists of four main modules that can be used in a stand-alone mode and in an integrated activity flow, exploiting the implemented automatic connections. The first module consists of a well-structured MySQL database developed to support all the other modules, thanks to a unified connection guaranteed by an ad-hoc developed Database Management Library managing the operations of data input and output from/to the database throughout the tool modules. The second module consists of a vehicle design routine and a mission design routine, supporting the design of a new vehicle and mission concept and assessing the main performance of an already existing configuration. The third module is estimating the cost of the system. Once the design is defined, it is possible to run a subsystem-level cost estimation. Using the subsystems’ masses estimated in the design routine, the parametric cost model provides useful insights into the potential development, manufacturing, and operating costs, as well as the cost and price per flight. Eventually, the developed methodology gives the possibility to generate a technology roadmap (fourth module). Supported by a database connection, the tool estimates each technology readiness and risk assessment and indicates the necessary activities, missions, and future works. This presentation highlights the use of IDREAM to rapidly prototype Martian space systems.

Artificial Intelligence techniques for space surveillance application: developing a detection tool of abnormal satellite behavior based on observed trajectories. (Moving to Mars Workshop: 17-18 November)

• Julien Côté-Massicotte (Artelys)
• carlyle deligny (artelys)

Room: Rooms A&B Space activity is constantly increasing with approximately 500,000 pieces of space debris orbiting the Earth. In this context, and to meet the operational needs of surveillance and analysis missions, the French innovation and defense agency (AID) launched a call for projects on artificial intelligence techniques for space surveillance. Artelys was selected to develop a tool (DASTra) for near-real-time detection of abnormal satellite behavior based on observed trajectories. Artelys aims at developing a tool for the classification of satellite characteristics according to its trajectory. The objective of this tool is to be able to identify the propulsive capabilities of an observed satellite, whether it is known or not. In operational conditions, DASTra will follow the trajectories of a set of satellites in real-time and its objective is to quickly identify the satellites whose trajectories become abnormal. After presenting the background and objectives of the project, we will review the approach adopted and the underlying challenges.

Status of MIRIAM-2 (Main Inflated Reentry Into the Atmosphere Mission test) a precursor Mission for the Mars Ballute ARCHIMEDES (Aerial Robot Carrying High resolution Imaging, Magnetometer Experiment and Direct Environmental Sensors) (virtual) (Moving to Mars Workshop: 17-18 November)

• Tanja Lehmann

Room: Rooms A&B Status of MIRIAM-2 (Main Inflated Reentry Into the Atmosphere Mission test) a precursor Mission for the Mars Ballute ARCHIMEDES (Aerial Robot Carrying High resolution Imaging, Magnetometer Experiment and Direct Environmental Sensors). Since 2003 the Mars Society Germany works on a project called ARCHIMEDES (Aerial Robot Carrying High Resolution Imaging, Magnetometer Experiment and Direct Environmental Sensors). This project aims to send a spacecraft with a folded balloon to Mars, inflate the balloon (also called ballute) outside of the martian atmosphere and perform an atmospheric entry by means of aerobraking, while at the same time scientific measurements will be performed, e.g. temperatures, pressures, magnetic field data, to name only a few. Currently the Mars Society is working on MIRIAM-2 (Main Inflated Reentry Into the Atmosphere Mission test 2), which is a sub-project to prove the scientific and technical concept for the ARCHIMEDES Mars mission. MIRIAM-2 is reduced in scale by 1:2,5 compared to the ARCHIMEDES probe and will be used for evaluation of the ballute systems and entry behaviour of the ballon into the atmosphere during a sounding rocket flight from Kiruna/Sweden. The MIRIAM-2 spacecraft will consist of 3 parts: The Camera Module Spacecraft (CMS), the Ballute Spacecraft (BSC) and the Service Spacecraft (SSC). The CMS will record the ballute inflation and separation and send the data back to the ground station for later evaluation. The SSC contains the ballute inflation system and the cold gas system and also the separation mechanism for deploying the ballute. The BSC consists of the ballute and an instrument pod carrying various scientific instruments for the purpose of determining the trajectory flown, the ballute behavior, the entry temperature and also scientific instruments. The talk will present the MIRIAM-2 probe and its technical features and scientific instruments, the design, manufacturing and testing of the spacecraft, the mission profile and goals and the current progress of the project.

Workshop closure (Moving to Mars Workshop: 17-18 November) Room: Rooms A&B