Planetary Exploration Research Articles

Alfred Otto Carl Nier: On the Shoulders of a Mass Spectrometry Giant.

This Perspective pays homage to Alfred Otto Carl Nier, whose substantial contributions were fundamental in shaping the mass spectrometry field into a key technology in research and industry. On the 30th anniversary of his passing, on May 16, 1994, this paper explores Nier's role in the field of mass spectrometry through an overview of his published works, key interviews, and archival material. Nier, originally an electrical engineer turned physicist, spent most of his scientific career at the University of Minnesota. His many innovations, both instrumental and methodological, encompassed advanced fields such as isotopic research, tracer studies, geochronology, or space research. Nier improved sector mass spectrometers, participated in the development of the isotope-ratio mass spectrometry field, developed a double-focusing sector mass spectrometer, and was a relevant member of the Manhattan Project. Today, Nier's influence persists, inspiring new generations of scientists engaged in cutting-edge research, from environmental studies to planetary exploration. His legacy thrives as current technologies and scientific strategies still echo his innovations and foresight.

Ablation simulation of integral woven gradient three‐dimensional thermal protection structures for planetary exploration

AbstractFor the harsh entry environment and higher thermal protection requirements, two structures of three‐dimensional woven gradient thermal protection materials were designed and prepared with the deep space exploration thermal protection system as the object. They are 3D orthogonal woven, 2.5D layer‐to‐layer angle interlock woven, 2.5D layer‐layer angle interlock woven structure(OLL) composite and 3D orthogonal woven, angle 2.5D layer‐to‐layer angle interlock woven, honeycomb structure(OLH) composite. Two materials were prepared and examined by ablation in an oxygen‐acetylene flame. A three‐dimensional macroscopic ablation model was established on the basis of the experiment, and the model was verified to be accurate and effective, which can well respond to the pyrolytic ablation process of the materials. The two designed materials are applied to the outsole of MSL by simulation, and the three‐dimensional response during the entry into Mars is simulated and analyzed in comparison with the thermal protection performance of PICA material. Both materials show better thermal protection than PICA and can be used as a reference in the selection of thermal protection materials.Highlights Two kinds of 3D gradient woven thermal protection materials are designed. A 3D thermal protection system response model is established. The three‐dimensional response during entry was analyzed. Thermal protection of the material is superior to that of PICA.

Real-time dual-parameter full-waveform inversion of GPR data based on robust deep learning

SUMMARY Ground penetrating radar (GPR) is becoming an increasingly important tool for understanding the shallow electrical structures of the Earth and planets due to its adaptability to harsh detection environments, efficient data acquisition and accurate detection results. GPR full-waveform can simultaneously constrain the permittivity and resistivity of the medium, providing more comprehensive geophysical information and reducing the non-uniqueness of inversion. However, given the highly non-linear inverse problem and the massive data resulted from high temporal and spatial samplings, traditional full-waveform inversion algorithms are prohibitively costly. Inspired by Google's vision semantic segmentation system, we develop a robust deep learning-guided network that integrates geology and geophysics knowledge to support the real-time translation of zero-offset GPR data into dual-parameter electrical structures. We test our proposed network using synthetic data, which demonstrates that the algorithm can provide an accurate dual-parameter electrical model from a GPR sounding in milliseconds on a common laptop PC, exhibiting high robustness and adaptability to noise interference and extreme values of model parameters. We also apply our network to field data gathered for pollutant investigation in the United States. The resulting dual-parameter structure provides a more comprehensive and realistic depiction of subsurface electrical properties and reveals the migration and ageing of pollutants. Our algorithm's real-time and accurate advantages are expected to further unleash the potential of GPR technology and enable it to play a more significant role in earth and planetary exploration.

EARTH AND PLANETARY INSIGHTS FOR HUMAN SUSTAINABILITY

Among different human activities having the goal to increase humanity’s quality of life as industrial, agricultural, commercial, transport, touristic ones, also activities connected to Earth and Planetary Insights must be mentioned. In this regard Earth and Planetary Insights especially by exploration, analysis and assessment encompass several scientific fields being an inter-, multi- and transdisciplinary task. The multitude of available approaches and existing applications of mentioned insights are covering almost all human activity fields ranging from main branches of Earth & Planetary Sciences such as for instance Surveying, Geology, in all its aspects, naming here hydrogeology, geotechnics, geophysics etc., Ecology and Environmental Sciences by considering relevant environmental elements such as air, water, soil, oceans, forests, as well as potential environmental impacts because of human activities such as environmental pollution and climate change, coming to Green, Nano- and Space Technologies, as well as to the use of renewable energy resources, all of them being interconnected by modern Management Tools. Space activities must be mentioned in the context of designing new technologies for researching our planet and Outer Space with its many celestial bodies, what means activities for planetary exploration. On the other side using space activities for getting human sustainability also means setting up regional and global emergency programs to support disaster response operations through the provision of satellite data being oriented to reduce disaster risks. With the vision of getting Earth and Planetary Insights for improving humanity quality of life, holistic thinking is per-se required, and in this context connected chances and challenges will be debated with the goal of assuring human sustainability. Developments on global level have emphasized that it depends on our mutual work and cooperation to prevent the increasing processes of current resources consumption from compromising the ability of future generations to meet their own needs.

Ephemeris accuracy improvement for moons of gas giants: a deep learning based method

Ephemerides accuracy of gas giant planetary system is of paramount importance in astronomical research, planetary exploration missions, and space navigation. Traditional mathematical methods face challenges when processing with data of different observation precisions, which may lead to extra noise and reduce the ephemeris accuracy. This paper proposes an Denoising Autoencoder based Method for Ephemeris Improvement (DAMEI) to improve the accuracy of ephemerides for moons in gas giant planetary system. Utilizing multiple sources of data efficiently, the DAMEI method can mitigate the impact of noise and uncertainty introduced by observational data with different precisions. Based on the symmetrical structure, the DAMEI method learns to encode essential motion features of gas giant planetary system into a latent space and captures the intricate patterns in planetary motion from observational data, subsequently decodes it to improve the ephemeris accuracy. The experimental results show that, for Jupiter’s major satellites (Galilean moons), the DAMEI method achieves more accurate ephemeris of up to 91.65% compared with current mathematical method. The proposed method is also assessed with satellites of Saturn, Uranus, and Neptune. It is shown that the DAMEI method also presents a better performance of up to 95.37%. The promising performance of DAMEI method can reduce the uncertainty introduced by low-accuracy data and improve ephemeris accuracy making the utmost of observational data with different precisions.

Experimental investigation and theoretical modeling of cutting mechanics using serrated tines in drilling lunar regolith simulant

Drilling is a widely used method for exploring extra-terrestrial bodies and seeking information on astrobiology, material composition, and evolution of the universe. The bit cutter of the drill tool is the main component that is in intense contact with the regolith and is of great importance for guaranteeing the cutting performance during drilling. The tine is a special type of cutter, and currently, there is no theoretical model describing its interaction with a lunar regolith simulant during cutting. To address this gap, semi-tine and full-tine cutting tests were performed at different cutting speeds, cutting depths, regolith densities, and tip angles. The experimental results showed that the regolith failure zone has an elliptical shape in the top view and a logarithmic spiral shape in the side view. Based on the failure pattern, a tine cutting mechanics model was built, and its results were compared with those of the experiments. The model exhibited good prediction accuracy for the cutting force, with a maximum error not exceeding 30.96% and an average error of 13.81%. To apply the model to extra-terrestrial drilling, a conical drill bit with multi-row serrated tines was designed. By analyzing the error between the theoretical and experimental values of the rotational torque, the model was further refined to provide a better match with the actual cutting results. The proposed cutting mechanics model describing the tine-regolith interaction mechanism can provide a reference for predicting drilling loads during planetary exploration.

Joint analysis of JUICE and Europa Clipper tracking data to study the Jovian system ephemerides and dissipative parameters

Context. Jupiter and its moons form a complex dynamical system that includes several coupling dynamics at different frequencies. In particular the Laplace resonance is fundamental to maintaining the energy dissipation that sustain Io’s volcanic activity and Europa’s subsurface ocean; studying its stability is thus crucial for characterizing the potential habitability of these moons. The origin and evolution of the Laplace resonance is driven by the strong tidal interactions between Jupiter and its Galilean moons, and the future planetary exploration missions JUICE and Europa Clipper could bring new light to this unsolved mechanism. During the Jupiter tours of both missions and JUICE’s Ganymede orbital phase, two-way radiometric range and Doppler data will be acquired between Earth ground stations and the spacecraft, which will be processed to recover the static and time-varying gravity field of the moons. Moreover, range and Doppler data will improve the orbit accuracy of the moons, providing precise measurements of Jupiter’s tidal parameters. Aims. This work presents a covariance analysis of the joint orbit determination of JUICE and Europa Clipper, aimed at quantifying the expected uncertainties on the main parameters that characterize the dynamics of the Jupiter system. Methods. We simulated radio science data from JUICE and Clipper missions under conservative noise assumptions, using a multi-arc approach to estimate the ephemerides and dissipation in the system. Results. Even though JUICE and Europa Clipper will not perform flybys of Io, the strong coupling with Europa and Ganymede will allow an improvement of our knowledge of the Jupiter-Io dissipation parameters thanks to JUICE and Europa Clipper radiometric data. Moreover, the expected uncertainty in Jupiter’s dissipation at the frequency of Callisto could unveil a potential resonance locking mechanism between Jupiter and Callisto.

Wide Dynamic Range, High Uniformity Spectral Irradiance Source for Calibration of Scientific-Grade, Large-Size Space Detectors

In order to meet the high uniformity calibration requirements for scientific-grade, large-size space detectors used in the CHES Extrasolar Planet Exploration Mission, this paper presents the design of a wide dynamic range, high uniformity spectral irradiance source (WHUIS). Utilizing a cascade integrating sphere design, and optimizing the overlapping area radiant flux adjustment structure and illumination light path, we achieve a wide dynamic range and high uniformity irradiance output. We established an irradiance transmission model based on the new assumption and analyzed the influence of factors such as illumination distance, stray light, and non-uniform radiance on the uniformity of irradiance output. The model is then validated by building experimental equipment. The findings show that in a circular area of 40 mm, the irradiance uniformity of our light source system exceeds 99.9%, and constant color temperature is adjustable within six orders of magnitude, consistent with the uniformity level predicted by the model.

Application of Improved Sliding Mode and Artificial Neural Networks in Robot Control

Mobile robots are autonomous devices capable of self-motion, and are utilized in applications ranging from surveillance and logistics to healthcare services and planetary exploration. Precise trajectory tracking is a crucial component in robotic applications. This study introduces the use of improved sliding surfaces and artificial neural networks in controlling mobile robots. An enhanced sliding surface, combined with exponential and hyperbolic tangent approach laws, is employed to mitigate chattering phenomena in sliding mode control. Nonlinear components of the sliding control law are estimated using artificial neural networks. The weights of the neural networks are updated online using a gradient descent algorithm. The stability of the system is demonstrated using Lyapunov theory. Simulation results in MATLAB/Simulink R2024a validate the effectiveness of the proposed method, with rise times of 0.071 s, an overshoot of 0.004%, and steady-state errors approaching zero meters. Settling times were 0.0978 s for the x-axis and 0.0902 s for the y-axis, and chattering exhibited low amplitude and frequency.

The role of low-cost robots in the future of spaceflight.

Lessons from the CubeSat and Mars Exploration programs may guide the infusion of robotics for planetary science and exploration.

Analysis of Cassini Altimetric Crossovers on Titan

The Cassini spacecraft performed several flybys of Saturn’s largest moon, Titan, collecting valuable data. During several passes, altimetric data were acquired. Here, we focus on altimetric measurements collected by Cassini’s radar when flying over the same region at different epochs in order to correlate such measurements (crossovers) and investigate differences in altimetry. In our study, we assess altimetric errors associated with three distinct methods for extracting topography from Cassini’s radar data: the maximum likelihood estimator (MLE), the threshold method, and the first moment technique. Focusing on crossover events, during which Cassini revisited specific areas of Titan’s surface, we conduct a detailed examination of the consistency and accuracy of these three topography extraction methods. The proposed analysis involves closely examining altimetric data collected at different epochs over identical geographical regions, allowing us to investigate potential errors due to the variations in off-nadir angle, relative impact, uncertainties, and systematic errors inherent in the application of these methodologies. Our findings reveal that the correction applied for the off-nadir angle to the threshold and first moment methods significantly reduces the dispersion in the delta difference at the crossover, resulting in a dispersion of the order of 60 m, even lower than what is achieved with the MLE (~70 m). Additionally, an effort is made to assess the potential of Cassini for estimating the tidal signal on Titan. Considering the altimetric errors identified in our study and the relatively low number of crossovers performed by Cassini, our assessment indicates that it is not feasible to accurately measure the tidal signal on Titan using the currently available standard altimetry data from Cassini. Our assessment regarding the accuracy of the Cassini altimeter provides valuable insights for future planetary exploration endeavors. Our study advances the understanding of Titan’s complex landscape and contributes to refining topographical models derived from Cassini’s altimetry observations. These insights not only enhance our knowledge of Saturn’s largest moon but also open prospects for Titan surface and interior exploration using radar systems.

NASA’s Capture, Containment, and Return System: Bringing Mars samples to Earth

The Mars Sample Return (MSR) campaign is one of the most ambitious and complex planetary science exploration missions ever pursued. With the participation of NASA, ESA, and many industry partners, MSR aims to bring Martian rock and atmosphere samples to Earth with the goal of answering key questions about Mars’ geological, climatological and, potentially, biological evolution. To accomplish this ambitious goal, the MSR campaign relies on three distinct flight elements and a ground element. The Earth Return Orbiter mission that would host the Capture, Containment, and Return System (CCRS) is the last flight element of the trio. The mission would capture the orbiting sample in low Mars orbit (launched into orbit by another mission), contain it, and return it to Earth, landing at the Utah Test and Training Range. Since its early architecture, several changes were adopted by CCRS to improve overall payload efficiency and reduce mass. This paper will discuss the CCRS design, how the current CCRS architecture contributes to an improved mission concept, and the next critical steps of the mission toward its launch.

Terramechanics analysis of climbing behavior of wheel against rigid obstacle on soft terrain

In the development of lunar and planetary exploration rovers, risk assessment in on-site environments comprising fine regoliths and unevenly distributed rocks is essential. To prevent a rover from being stuck during its operation, one must understand the behavior of its wheel when it climbs over rigid obstacles in off-road environments. In this study, we apply an extended terramechanics model, which can reasonably describe the interaction between soft ground and vehicles, to analyze the obstacle-climbing behavior of rigid wheels. To describe the interaction between the wheel and a hard obstacle, we combine the penalty method with the extended terramechanics model. Subsequently, we verify the effectiveness of the proposed method by comparing its results with those of a traversing single wheel obtained from a laboratory experiment. Furthermore, we use the model to perform a multibody dynamics analysis on a simple rover, where its applicability to the examination of the overall performance of obstacle climbing is demonstrated.

A solvent-free processed low-temperature tolerant adhesive

Ultra-low temperature resistant adhesive is highly desired yet scarce for material adhesion for the potential usage in Arctic/Antarctic or outer space exploration. Here we develop a solvent-free processed low-temperature tolerant adhesive with excellent adhesion strength and organic solvent stability, wide tolerable temperature range (i.e. −196 to 55 °C), long-lasting adhesion effect ( > 60 days, −196 °C) that exceeds the classic commercial hot melt adhesives. Furthermore, combine experimental results with theoretical calculations, the strong interaction energy between polyoxometalate and polymer is the main factor for the low-temperature tolerant adhesive, possessing enhanced cohesion strength, suppressed polymer crystallization and volumetric contraction. Notably, manufacturing at scale can be easily achieved by the facile scale-up solvent-free processing, showing much potential towards practical application in Arctic/Antarctic or planetary exploration.

Reversible kink instability drives ultrafast jumping in nematodes and soft robots.

Entomopathogenic nematodes (EPNs) exhibit a bending-elastic instability, or kink, before becoming airborne, a feature hypothesized but not proven to enhance jumping performance. Here, we provide the evidence that this kink is crucial for improving launch performance. We demonstrate that EPNs actively modulate their aspect ratio, forming a liquid-latched closed loop over a slow timescale O (1 s), then rapidly open it O (10 µs), achieving heights of 20 body lengths (BL) and generating ∼ 10 4 W/Kg of power. Using jumping nematodes, a bio-inspired Soft Jumping Model (SoftJM), and computational simulations, we explore the mechanisms and implications of this kink. EPNs control their takeoff direction by adjusting their head position and center of mass, a mechanism verified through phase maps of jump directions in simulations and SoftJM experiments. Our findings reveal that the reversible kink instability at the point of highest curvature on the ventral side enhances energy storage using the nematode's limited muscular force. We investigated the impact of aspect ratio on kink instability and jumping performance using SoftJM, and quantified EPN cuticle stiffness with AFM, comparing it with C. elegans . This led to a stiffness-modified SoftJM design with a carbon fiber backbone, achieving jumps of ∼25 BL. Our study reveals how harnessing kink instabilities, a typical failure mode, enables bidirectional jumps in soft robots on complex substrates like sand, offering a novel approach for designing limbless robots for controlled jumping, locomotion, and even planetary exploration.

Seismic Anisotropy From 6C Ground Motions of Ambient Seismic Noise

AbstractWe propose a new approach capable of measuring local seismic anisotropy from 6C (three‐component translation and three‐component rotation) amplitude observations of ambient seismic noise data. Our recent theory demonstrates that the amplitude ratio of 6C cross‐correlation functions (CCFs) enables retrieving the local phase velocity. This differs from conventional velocity extraction methods based on the travel time. Its local sensitivity kernel beneath the 6C seismometer allows us to study anisotropy from azimuth‐dependent CCFs, avoiding path effects. Such point measurements have great potential in planetary exploration, ocean bottom observations, or volcanology. We apply this approach to a small seismic array at Pion Flat Observatory (PFO) in southern California, array‐deriving retrieves rotational ground motions from microseismic noise data. The stress‐induced anisotropy is well resolved and compatible with other tomography results, providing constraints on the origin of depth‐dependent seismic anisotropy.

Mole‐Inspired Robot Burrowing with Forelimbs for Planetary Soil Exploration

Mole‐Inspired Robot Burrowing with Forelimbs for Planetary Soil Exploration

Design of a Spherical Rover Driven by Pendulum and Control Moment Gyroscope for Planetary Exploration

The spherical shape is an interesting approach to develop exploration robots, or rovers, thanks to its capability of ensuring omnidirectional motion and of being basically unsensitive to possible rollovers. This works intends to propose a novel detailed design for such a kind of robot and to discuss the performance that can be reached by adopting this solution. The work hence introduces the requirements assumed for the design of the robot and discloses the general layout that was selected, which includes a pendulum for motion transmission and two coupled gyroscopes to overcome high, steep obstacles, such as steps. The paper then summarizes the functional design computation carried out to size and selects the components of the system. Eventually, a control algorithm is described and tested on a complete multibody model of the robot. The results in the execution of standard maneuvers such as motion on a horizontal plane, as well as in the overcome of a step, are shown. The energetic balance of the rover is described, and some preliminary consideration about mission planning are reported in the final discussion.

Scheduled hypometabolism and hypothermia at the crossroads of deep space manned mission and longevity

Spaceflight is a mysterious ageing/rejuvenation transition. It is associated with factors of evolutionary unfamiliar to the earth's inhabitants — microgravity, cosmic rays and solar wind irradiation, failure of circadian rhythms and numerous other singularities. For still unknown reasons, spaceflight provokes quick acceleration of almost all hallmarks of ageing and age-related diseases. The alterations have a transitory character and disappear in the post-landing adaptation period. The posited ageing/rejuvenation transition could be repeated over multiple flights. This should be confirmed by epigenetic or other types of ageing clocks. Hypometabolism and hypothermia are considered efficient protectors from the hazards of space missions while saving energy and food intake. The two most discussed approaches are based on the idea of dormancy (synthetic torpor) or excessive sleeping (shallow metabolic depression). We suggest another model of metabolic depression induced by a rebreathing hypoxic-hypercapnic environment (HHE), which is accompanied by ‘voluntary’ calorie restriction. Crewmembers' work schedules can be designed to allow crewmembers to maintain normoxic levels during energy-demanding activities and transition to HHE during rest periods. A computerized tracking system can harmonize daily schedules with personalized HHE. The resulting scheduled hypometabolothermia (SHMT) could optimise energy expenditure without compromising productivity and be applicable during spaceflight and upon arrival at a destination and subsequent planetary exploration. We envision SHMT as a major human lifestyle on Earth as well. Of course, only further thorough explorations will reveal all the advantages and pitfalls of HHE and SHMT on Earth and in space. ________________________________________________________________________________________Keywords: hypoxia and hypercapnia; metabolic suppression; food consumption; space mission; longevity

Radiation-induced alteration of apatite on the surface of Mars: first in situ observations with SuperCam Raman onboard Perseverance

Planetary exploration relies considerably on mineral characterization to advance our understanding of the solar system, the planets and their evolution. Thus, we must understand past and present processes that can alter materials exposed on the surface, affecting space mission data. Here, we analyze the first dataset monitoring the evolution of a known mineral target in situ on the Martian surface, brought there as a SuperCam calibration target onboard the Perseverance rover. We used Raman spectroscopy to monitor the crystalline state of a synthetic apatite sample over the first 950 Martian days (sols) of the Mars2020 mission. We note significant variations in the Raman spectra acquired on this target, specifically a decrease in the relative contribution of the Raman signal to the total signal. These observations are consistent with the results of a UV-irradiation test performed in the laboratory under conditions mimicking ambient Martian conditions. We conclude that the observed evolution reflects an alteration of the material, specifically the creation of electronic defects, due to its exposure to the Martian environment and, in particular, UV irradiation. This ongoing process of alteration of the Martian surface needs to be taken into account for mineralogical space mission data analysis.