Planetary Surface Research Articles

A Heuristic-Guided Dynamical Multi-Rover Motion Planning Framework for Planetary Surface Missions

We present a heuristic-guided multi-robot motion planning framework that solves the problem of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i> dynamical agents visiting <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</i> unlabeled targets in a partially known environment for planetary surface missions without solving the two-point boundary value problem (BVP). The framework design is motivated by typical planetary surface mission constraints of limited power, limited computation, and limited communication. The framework maintains a centralized, dynamically updated probabilistic roadmap (PRM) that incorporates new obstacle updates as the agents move in the environment. The dynamic roadmap captures the changing obstacle topology and provides updated cost-to-go heuristics to accelerate each agent's independent single-query motion-planning process. The agents use a feasible sampling-based motion planner without computing the BVP while leveraging the roadmap heuristics to quickly plan and visit their assigned target. The agents handle robot-robot and robot-obstacle collision avoidance in a decentralized fashion. We conduct multiple simulation experiments using robots with non-linear dynamics to show our planner performs better in overall planning time and mission time than approaches not using the roadmap heuristic. We also field our algorithm on prototype rovers and demonstrate the viability of implementing our algorithm on real-world hardware platforms.

Pioneers project: Looking inside planetary interiors

Pioneers project: Looking inside planetary interiors PIONEERS European project develops the next generation of instruments that will reveal planetary interiors, explains Professor Raphael F. Garcia from ISAE-SUPAERO. After decades of exploration of planetary surfaces, our knowledge of planetary interiors and internal structures remains very limited. However, the structure of a planetary body tells us a lot about how it formed and evolved during the last 4.5 billion years. It is critical to understand our solar system to know better the thousands of planets orbiting other stars in our galaxy. Are these planets water-rich? for how long? Can these sustain life? Even at the scale of our solar system these questions are not fully solved because the clues to their answers are hidden deep inside our nearby planets, their moons, and asteroid bodies. Even if all these objects formed from the same materials that formed our Sun, the hazard of accretion generated very different objects evolving differently.

Astrovirology: how viruses enhance our understanding of life in the Universe.

Viruses are the most numerically abundant biological entities on Earth. As ubiquitous replicators of molecular information and agents of community change, viruses have potent effects on the life on Earth, and may play a critical role in human spaceflight, for life-detection missions to other planetary bodies and planetary protection. However, major knowledge gaps constrain our understanding of the Earth's virosphere: (1) the role viruses play in biogeochemical cycles, (2) the origin(s) of viruses and (3) the involvement of viruses in the evolution, distribution and persistence of life. As viruses are the only replicators that span all known types of nucleic acids, an expanded experimental and theoretical toolbox built for Earth's viruses will be pivotal for detecting and understanding life on Earth and beyond. Only by filling in these knowledge and technical gaps we will obtain an inclusive assessment of how to distinguish and detect life on other planetary surfaces. Meanwhile, space exploration requires life-support systems for the needs of humans, plants and their microbial inhabitants. Viral effects on microbes and plants are essential for Earth's biosphere and human health, but virus-host interactions in spaceflight are poorly understood. Viral relationships with their hosts respond to environmental changes in complex ways which are difficult to predict by extrapolating from Earth-based proxies. These relationships should be studied in space to fully understand how spaceflight will modulate viral impacts on human health and life-support systems, including microbiomes. In this review, we address key questions that must be examined to incorporate viruses into Earth system models, life-support systems and life detection. Tackling these questions will benefit our efforts to develop planetary protection protocols and further our understanding of viruses in astrobiology.

Establishing a Best Practice for SDTrimSP Simulations of Solar Wind Ion Sputtering

Solar wind (SW) ion irradiation on airless bodies can play an important role in altering their surface properties and surrounding exosphere. Much of the ion sputtering data needed for exosphere studies come from binary collision approximation sputtering models such as TRansport of Ions in Matter and its more recent extension, SDTrimSP. These models predict the yield and energy distribution of sputtered atoms, along with the depth of deposition and damage of the substrate, all as a function of the incoming ion type, impact energy, and impact angle. Within SDTrimSP there are several user-specific inputs that have been applied differently in previous SW ion sputtering simulations. These parameters can influence the simulated behavior of both the target and sputtered atoms. Here, we have conducted a sensitivity study into the SDTrimSP parameters in order to determine a best practice for simulating SW ion impacts onto planetary surfaces. We demonstrate that ion sputtering behavior is highly sensitive to several important input parameters including the ion impact angle and energy distribution and the ejected atom surface binding energy. Furthermore, different parameters can still result in similarities in the total sputtering yield, potentially masking large differences in other sputtering-induced behaviors such as the elemental yield, surface concentration, and damage production. Therefore, it is important to consider more than just the overall sputtering behavior when quantifying the importance of different parameters. This study serves to establish a more consistent methodology for simulations of SW-induced ion sputtering on bodies such as Mercury and the Moon, allowing for more accurate comparisons between studies.

Development of a NASA roadmap for planetary protection to prepare for the first human missions to Mars

As part of planning for future space exploration, COSPAR (The Committee on Space Research) together with participating space agencies, organized and held interdisciplinary meetings to consider next steps in addressing knowledge gaps for planetary protection for future human missions to Mars. Beginning with the results of these meetings and earlier work by NASA, ESA, and COSPAR (e.g., Criswell et al., 2005; Hogan et al., 2006; Rummel et al., 2008) as a base the authors of this paper carried out a follow-on NASA planning activity to identify the necessary steps to be accomplished to close knowledge gaps. We identified significant overlap between the planetary protection needs and other sets of Mars preparation roadmaps (1) microbial monitoring requirements for crew health and medical systems, (2) studies of the microbiome of the built environment, (3) environmental control and life support systems (ECLSS), (4) waste management, and (5) planetary surface operations. In many cases, efforts to mature exploration class systems for Mars that are occurring in other domains can be leveraged with minor changes to address planetary protection gaps as well. In other cases, work planned for testing on the International Space Station (ISS) as an analog for crew Mars transit, or on the lunar surface as an analog for Mars surface operations can be used to close planetary protection technology and knowledge gaps. An overall strategic framework that combines these domains has the advantage of being more comprehensive, efficient, and timely for closing gaps.This approach has led to the development of a NASA roadmap for addressing planetary protection integrated with other related roadmaps. NASA's development and execution of the planetary protection is now viewed in an integrated way with related technology development and testing. Key features of the integrated capabilities roadmap include:•A focus on microbial monitoring needs for crewed systems overall, and the additional work needed to develop and demonstrate baseline vs. abnormal changes in microbial communities over time.•Integrated consideration of planetary protection and crew health requirements relevant to crew quarantine and science sample transportation.•Specific and targeted studies of microbial growth and biofilms in microgravity and lunar surface ECLSS systems.•Development of sterilization, cleaning, and waste handling technologies that meet habitation needs as well as planetary protection needs.

Connecting Hemispheric Asymmetries of Planetary Albedo and Surface Temperature

AbstractSatellite measurements show that the Northern and Southern hemispheres reflect equal amounts of shortwave radiation (“albedo symmetry”), but no theory exists on if, how, and why the symmetry is established and maintained. Ambiguously, climate models are strongly biased in albedo symmetry but agree in the sign of the response to CO2. We find that mean‐state biases in albedo symmetry and hemispheric surface temperature asymmetry correlate negatively. Similarly, the response of albedo asymmetry to CO2 forcing correlates negatively with the magnitude of the asymmetry in surface warming. This is true across many and within single climate model simulations: a too warm or stronger warming hemisphere is darker or darkens more than its counterpart. In the 21 years of observations we find the same tendency and hypothesize (a) albedo symmetry is a function of the current climate state and (b) we will observe an evolution toward albedo asymmetry in coming decades.

Inverting resolution: accounting for the planetary cost of earth observation

This article uses the resolutional relationship between digital image and planetary surface in satellite remote sensing as a lens through which to view the reliance of visual culture on mineral resources. While most studies of resolution in satellite imaging have focused on visibility and invisibility, the author argues that the equivalence between pictorial and geographic space in its cm/pixel specification offers an opportunity to consider the physical relationship between the two. The proposed inversion enables the satellite and its transmitted images to be understood as contingent upon an unsustainably extractive industrial model. The article then traces the material trajectory in geophysical prospecting applications of remote sensing, identifying a recursive loop in which images are used to produce minerals that are used to produce images. The potential geopolitical impact of this circularity is then assessed with regard to an example of future remote sensing emissions governance. In this, and many other climate-critical applications, remote sensing potentially plays a vital role, yet its instrumental gaze tends to shape the earth as an informational resource whose mineral reserves should be capitalized upon. Ultimately, the author’s aim is not to denounce earth observation as ecologically untenable, but to propose that we find a measure with which to assess the planetary impact of the various aspects of industrialized visual culture. Conceiving of resolution not as a measure of pictorial space but of the terrestrial cost of producing, consuming, distributing and permanently storing digital images might enable a more relational understanding of image and ground, pixels and planet. Accounting for the inverse resolution of an image could bring the deep temporal costs of digital visual culture into focus.

Распределение плотности в газовой оболочке планеты

Purpose: Theoretical study of gas density distribution around the planet given self-gravity. Methods: Proposed in this paper equations for the planet gaseous envelope density with corresponding boundary conditions are solved analytically and numerically by Runge-Kutta method. Results: For the first time, the analysis of numerical solution of equations for all the space where the planet gravitational influence prevails - in the distance range from the planet surface till Hill radius - has been pursued using similarity method. Near the planet, the solution coincides with classical barometric formula, at intermediary distances, - with barometric formula which takes into consideration the dependence of free fall acceleration from the distance till the planet, at large distances, - with the dependence of density for singular isothermal gas sphere due to self-gravity. Practical significance: On the basis of the solution obtained, the unified picture of the planet gaseous envelope density distribution was analyzed. The results presented in the paper can be useful both for university physics professors and for the researchers involved in astrophysics.

Impact Induced Oxidation and Its Implications for Early Mars Climate

AbstractH2 in a CO2 atmosphere may serve as a potential solution to the early Mars climate paradox, but its unknown sources cast doubts on the proposed mechanism. Impact cratering is an energetic process that may modify the surface redox budget. Here, we investigate the potential influence of impact‐related melt oxidation and serpentinization on global climate conditions. We show that impact melt and the projectile's significant oxidizing potential during basin‐forming impacts (Basin size ≥1,250 km) result in sufficient H2 to raise the global mean temperature to above 273K, which lasts for up to 105 − 106 yr considering rate‐limited regime. Impact‐induced serpentinization has limited consequences on the global climate in comparison. Episodic warming after large impacts may have enabled the presence of liquid water for up to several million years in the Noachian, resulting in the chemical evolution of the planet's surface co‐evolving with the planetary atmosphere in an episodic manner.

A Semantic View on Planetary Mapping—Investigating Limitations and Knowledge Modeling through Contextualization and Composition

The concept of planetary mapping constitutes different activities within different contexts. Much like the field of cartography, it is an amalgamation of science, techniques, and artistic disciplines. It has undergone considerable changes over the last decades to cope with increasing demands related to data management, analysis, and visualization. Planetary mapping employs abstraction, which involves simplifications and generalizations. It aims to produce accessible visualization of planetary surfaces to gain insights and knowledge. Here, we show that different manifestations of this concept are interdependent and we discuss how different mapping concepts relate to each other semantically. We reason that knowledge gain can only be achieved through thematic mapping. The reasoning for systematic mapping and exploration is an intellectual product of thematic mapping. In order to highlight these relationships, we (a) develop in-depth definitions for different types of planetary mapping, (b) discuss data and knowledge flow across different mapping concepts, and (c) highlight systemic limitations related to data that we acquire and attempt to abstract through models. We finally develop a semantic proto-model that focuses on the transformation of information and knowledge between mapping domains. We furthermore argue that due to compositionality, map products suffer not only from abstraction but also from limitations related to uncertainties during data processing. We conclude that a complete database is needed for mapping in order to establish contextualization and extract knowledge. That knowledge is needed for reasoning for planning and operational decision making. This work furthermore aims to motivate future community-based discussions on functional semantic models and ontologies for the future development of knowledge extraction from thematic maps.

A method for constructing an interplanetary trajectory of a spacecraft to Venus using resonant orbits to ensure landing in the desired region

A problem of constructing the trajectory of a spacecraft flight to Venus within the framework of a mission including landing of a lander in a given region of the planet's surface is being considered. A new celestial mechanics related method based on the use of gravity assist maneuver near Venus is proposed to transfer the spacecraft to a heliocentric orbit resonant with the orbit of Venus, so that, at the next approach the planet, the given region of the surface becomes attainable for landing. It is shown that the best resonant orbit in terms of the cost of the characteristic velocity is an orbit with a 1:1 ratio of the period to the orbital period of Venus. A procedure for choosing one of possible resonant orbits depending on coordinates of the desired landing point on the surface and the launch date of the mission is described. An example of calculating the flight trajectory that ensures landing in the Vellamo-South region of the Venus surface at launch from the Earth in 2031 is considered.

Exploring the transition between water- and wind-dominated landscapes in Deep Springs, California, as an analog for transitioning landscapes on Mars

Abstract. Many planetary surfaces have been shaped by eolian and fluvial processes, and understanding the resulting landscape is of critical importance to understanding changes in climate. Surface features on Earth and Mars are commonly observed using a variety of remote sensing methods. The observed geomorphology provides evidence of present processes and paleo-processes, but interpretations are limited by the resolution of the data and similarity to well-understood systems on Earth. In this work, we study a complex fluvio-lacustrine and eolian landscape at Deep Springs playa, California, using field measurements and remote sensing as an analog for a wet-to-dry-transitioning landscape on Mars. The playa system in arid Deep Springs reflects fluvio-lacustrine processes in its interior but transitions to eolian-dominated processes along the playa margin. Weather station data and field observations collected over 34 months illustrate the interplay between eolian and lacustrine processes and provide context for interpreting the observed geomorphology in aerial images. Our results showed a consistent distal-to-proximal geomorphic transition in the landscape defined by the changing expression of polygonal fractures, wave ripples, and evaporite deposits. Crescent-shaped sedimentary deposits, originally suspected to be related to barchan dunes, proved unrelated to eolian processes. We discuss the processes, sedimentary features, and climate drivers at Deep Springs to provide a potential framework for identifying and interpreting similar interactions between fluvio-lacustrine and eolian geomorphology elsewhere on Earth, on Mars, and beyond.

Special spherical mobile robot for planetary surface exploration: A review

Considering the requirements of high scientific return, low cost, less complexity, and more reliability for the robot proposed by the extreme environment exploration task on the planet surface, this article comprehensively reviews the history of the special spherical robot used for extraterrestrial surface exploration and summarizes the environmental characteristics and task difficulties of different planet surface. This article compares the advantages of different types of ground spherical robots and points out the superiority of special spherical robots, such as omni-direction, airtightness, zero-radius turning, under-actuated, swarming, and lightweight. In addition, the research progress of special spherical robots for extraterrestrial exploration, such as wind ball, jumping ball, fly ball, ball with leg, pendulum driven ball, tensegrity structure, are reviewed respectively. Finally, the performance characteristics of all these robots are analyzed, their application scope given.

Experimental study of frost detectability on planetary surfaces using multicolor photometry and polarimetry

When the temperature and pressure conditions allow it, water ice can deposit as frost on the regolith of planetary surfaces. Frost is an important indicator of the surface physical conditions, and may trigger geological processes by its deposition and sublimation. This works aims to explore, experimentally, the possibility of detecting early stages of frost formation and to characterize its spectrophotometric and spectropolarimetric signatures in visible reflected light. We deposit ice on top of different regolith simulants, measuring the dust temperature, the thickness, and the morphology of the frost through a microscope, while measuring the reflected light at phase angles of 50° and 61°, and the linear polarization at phase angles of 5° and 16°, at three different wavelengths (450, 550, and 750nm). We show that both the spectral slope (in particular between 450–550nm), and the difference of polarization between 450 and 750nm are efficient methods to detect frost layers with thicknesses as low as 10 to 20µm. Furthermore, we find that the linear polarization at 16° relates to the temperature of the regolith i.e. the type of the deposited ice crystalline structure.

Seismo-acoustic coupling efficiency at the surface of Venus

The extreme conditions at the surface of Venus pose a challenge for monitoring the planet’s seismic activity using long-duration landed probes. One alternative is using balloon-based sensors to detect venusquakes from the atmosphere. This presentation assesses the efficiency of seismic-to-acoustic energy transfer from Venus' crust to its deep atmosphere. It is, therefore, restricted to immediate neighborhood of the planet's surface. In order to account for supercritical conditions near the surface, the Peng-Robinsonequation of state is used to obtain the acoustic wavenumber in the lower atmosphere. The energy transported across the surface from deep and shallow sources is two orders of magnitude larger than on Earth, pointing to a very strong seismo-acoustic coupling. For a more realistic scenario, we simulated the acoustic field generated in the lower atmosphere by the ground motion arising from a vertical array of subsurface point-force sources. The resulting transmission loss maps show a strong epicentral cone accompanied by contributions from leaky surface waves.

Modeling support to acoustic sensing at the surface of Mars

Acoustic propagation in the atmosphere of Mars is the subject of renewed interest since the presence of microphones on the surface of the red planet. The analysis of the recordings collected by the SuperCam microphone of the NASA Perseverance rover has already shown that the acoustic properties of Mars atmosphere do fit the existing models, and so far, the meteorological data have been available. On this basis, classical atmospheric propagation models have been adapted, including the effects of ground, temperature gradient, wind, and turbulence. A sensitivity study is presented, using two configurations that correspond to the main actual sources and propagation paths experienced on Mars : one similar to the point-like pulsed source that is generated by the expansion of the plasma of the LIBS technique, and the other analogue to the tonal low frequency noise emission of the ingenuity drone. Modeling results show to what extend this two configurations can be use to assess ground or atmospheric properties.

Scattered polarized radiation of extrasolar circumplanetary rings

Aims. We have investigated the impact of circumplanetary rings consisting of spherical micrometer-sized particles on the net scattered light polarization of extrasolar gas giants. Methods. Using the three-dimensional Monte Carlo radiative transfer code POLARIS, we studied the impact of the macroscopic parameters that define the ring, such as its radius and inclination, and the chemical composition of the ring particles on the net scattered polarization. For the spherical ring particles, we applied the Mie scattering theory. We studied the flux and polarization of the scattered stellar radiation as a function of planetary phase angle and wavelength from the optical to the near-infrared. Results. For the chosen grain size distribution, the dust particles in the ring show strong forward scattering at the considered wavelengths. Thus, the reflected flux of the planet dominates the total reflected and polarized flux at small phase angles. However, the scattered and polarized flux of the ring increase at large phase angles and exceeds the total reflected planetary flux. For large rings that contain silicate particles, the total reflected flux is dominated by the radiation scattered by the dust in the ring at all phase angles. As a result, the orientation of polarization is parallel to the scattering plane at small phase angles. In contrast, for a ring that contains water ice particles, the orientation of polarization is parallel to the scattering plane at large phase angles. Depending on the ring inclination and orientation, the total reflected and polarized flux show a specific distribution as well. Large particles show a strong polarization at large phase angles compared to smaller particles. For a Jupiter-like atmosphere that contains methane and aerosols, methane absorption features are missing in the spectrum of a ringed planet. Conclusions. Scattering of the stellar radiation by dust in circumplanetary rings of extrasolar planets results in unique features in the phase-angle- and wavelength-dependent reflected and polarized net flux. Thus, exoplanet polarimetry provides the means to study not only the planetary atmosphere and surface, but also to identify the existence and constrain the properties of exoplanetary rings.

Spectroscopic Characterization of Impactites and a Machine Learning Approach to Determine the Oxidation State of Iron in Glass‐Bearing Materials

AbstractWe investigated a suite of impact glass‐bearing rocks using a multi‐analytical approach including visible‐near‐infrared diffuse reflectance spectroscopy, Mössbauer spectroscopy, and powder X‐ray diffraction. In order to better understand and interpret the obtained results, we built a database containing physical, chemical, and spectroscopic information on glasses and glass‐bearing materials using new results from this study and published works. We used the database to explore systematic relationships between parameters of interest and finally we applied several machine learning algorithms (support vector machine, random forests, and gradient boosting) to test the possibility to regress the oxidation state of iron from chemical and spectroscopic information. Our results show that even small amounts of mafic crystalline phases have a big influence on the spectral features of glass‐bearing rocks. Samples without mafic crystalline inclusions show the typical spectrum of glasses (two broad and shallow bands roughly centered around 1,100 and 1,900 nm) with minor variations due to bulk chemistry. We described a non‐linear relationship between average reflectance (average reflectance value between 500 and 1,000 nm), FeO + TiO2 content, grain size, and Fe3+/FeTOT. We tested the relation for the finer grain size (0–25 μm), and we qualitatively assessed how it is affected by grain size, Fe3+/FeTOT, and crystal content. Finally, we developed a machine learning pipeline to regress the Fe3+/FeTOT of glass‐bearing materials using the proposed database. Our machine learning calculations give satisfactory results (MAE: 0.0321) and additional data will enable the application of our computational strategy to remotely acquired data to extract chemical and mineralogical information of planetary surfaces.

YOLOLens: A Deep Learning Model Based on Super-Resolution to Enhance the Crater Detection of the Planetary Surfaces

The impact crater detection offers a great scientific contribution in analyzing the geological processes, morphologies and physical properties of the celestial bodies and plays a crucial role in potential future landing sites. The huge amount of craters requires automated detection algorithms, and considering the low spatial resolution provided by the satellite jointly with, the solar illuminance/incidence variety, these methods lack their performance in the recognition tasks. Furthermore, small craters are harder to recognize also by human experts and the need to have a sophisticated detection algorithm becomes mandatory. To address these problems, we propose a deep learning architecture refers as “YOLOLens5x”, for impact crater detection based on super-resolution in a unique end-to-end design. We introduce the entire workflow useful to link the Robbins Lunar catalogue with the tiles orthoprojected from the Lunar mosaic LROC mission in order to train our proposed model as a supervised paradigm and, the various optimization due to provide a clear dataset in the training step. We prove by experimental results a boost in terms of precision and recall than the other state-of-the-art crater detection models, reporting the lowest error estimated craters diameter using the same scale factor given by LROC WAC Camera. To simulate the camera satellite at the lowest spatial resolution, we carried out experiments at different scale factors (200 m/px, 400 m/px) by interpolating the source image of 100 m/px, bringing to light remarkable results across all metrics under consideration compared with the baseline used.

What Models Tell Us About the Evolution of Carbon Sources and Sinks over the Phanerozoic

The current rapid increase in atmospheric CO2, linked to the massive use of fossil fuels, will have major consequences for our climate and for living organisms. To understand what is happening today, it is informative to look at the past. The evolution of the carbon cycle, coupled with that of the past climate system and the other coupled elemental cycles, is explored in the field, in the laboratory, and with the help of numerical modeling. The objective of numerical modeling is to be able to provide a quantification of the processes at work on our planet. Of course, we must remain aware that a numerical model, however complex, will never include all the relevant processes, impacts, and consequences because nature is complex and not all the processes are known. This makes models uncertain. We are still at the beginning of the exploration of the deep-time Earth. In the present contribution, we review some crucial events in coupled Earth-climate-biosphere evolution over the past 540 million years, focusing on the models that have been developed and what their results suggest. For most of these events, the causes are complex and we are not able to conclusively pinpoint all causal relationships and feedbacks in the Earth system. This remains a largely open scientific field. ▪The era of the pioneers of geological carbon cycle modeling is coming to an end with the recent development of numerical models simulating the physics of the processes, including climate and the role of vegetation, while taking into account spatialization.▪Numerical models now allow us to address increasingly complex processes, which suggests the possibility of simulating the complete carbon balance of objects as complex as a mountain range.▪While most of the processes simulated by models are physical-chemical processes in which the role of living organisms is taken into account in a very simple way, via a limited number of parameters, models of the carbon cycle in deep time coupled with increasingly complex ecological models are emerging and are profoundly modifying our understanding of the evolution of our planet's surface.