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1. Earth and Mars – Distinct inner solar system products

   https://doi.org/https://doi.org/10.1016/j.chemer.2021.125746  

   Yoshizaki, T. (February 2021, Chemie der Erde)

   null (Ed.)

   Composition of terrestrial planets records planetary accretion, core–mantle and crust–mantle differentiation, and surface processes. Here we compare the compositional models of Earth and Mars to reveal their characteristics and formation processes. Earth and Mars are equally enriched in refractory elements (1.9 × CI), although Earth is more volatile-depleted and less oxidized than Mars. Their chemical compositions were established by nebular fractionation, with negligible contributions from post-accretionary losses of moderately volatile elements. The degree of planetary volatile element depletion might correlate with the abundances of chondrules in the accreted materials, planetary size, and their accretion timescale, which provides insights into composition and origin of Mercury, Venus, the Moon-forming giant impactor, and the proto-Earth. During its formation before and after the nebular disk’s lifetime, the Earth likely accreted more chondrules and less matrix-like materials than Mars and chondritic asteroids, establishing its marked volatile depletion. A giant impact of an oxidized, differentiated Mars-like (i.e., composition and mass) body into a volatile-depleted, reduced proto-Earth produced a Moon forming debris ring with mostly a proto-Earth’s mantle composition. Chalcophile and some siderophile elements in the silicate Earth added by the Mars-like impactor were extracted into the core by a sulfide melt (~0.5% of the mass of the Earth’s mantle). In contrast, the composition of Mars indicates its rapid accretion of lesser amounts of chondrules under nearly uniform oxidizing conditions. Mars’ rapid cooling and early loss of its dynamo likely led to the absence of plate tectonics and surface water, and the present-day low surface heat flux. These similarities and differences between the Earth and Mars made the former habitable and the other inhospitable to uninhabitable. 

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2. The Ironberry Plan: an Electric and Steel-making Way to Build a Science Station on Mars

   https://doi.org/10.59332/jbis-077-03-0091  

   Olsen, Rif Miles (July 2024, Journal of the British Interplanetary Society)

   This paper introduces the Ironberry Plan. This practical plan leads to the construction of a science station in the iron region of the Meridiani Planum (IRoM), Mars. It also enables the continuation of NASA’s Water Strategy, the beginning of astronomy from Mars, the landing of humans at IRoM and the beginning of continuous human habitation there. A focus of the plan is to provide abundant electricity on Mars through an intense use of local resources. The characteristic early steps of the Ironberry Plan are: 1. The robotic harvesting and processing of a superb iron ore at IRoM; 2. The use of Mars-optimized, robot-controlled steel-making and manufacture of steel parts; 3. At least for some years, a deliberate push for mutually feeding exponential growth in electricity generation, steel-making and steel manufacture, where early steel manufacture is focused on making more electrical generation equipment; 4. Using the rapidly growing power capacity and advanced robotics and processing of local sediments, the start of many more foundational activities (i.e., water liberation, sulfur-concrete construction, multi-material manufacture, agriculture and more); 5. Using 1-4, the building of a science station at IRoM while also converting excavated sediment caverns into underground, radiation protected spaces for the science station. Keywords: Ironberries, Iron Region of the Meridiani Planum (IRoM), Science Station, Abundant Electricity, Steel-making 

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3. Enhanced Oxygen Ion Outflow at Earth and Mars due to the Concurrent Impact of a Stream Interaction Region

   https://doi.org/10.3847/1538-4357/ad307a  

   Venugopal, Indu; Thampi, Smitha V; Bhaskar, Ankush; Venkataraman, V (April 2024, The Astrophysical Journal)

   Abstract One of the major processes that solar wind drives is the outflow and escape of ions from the planetary atmospheres. The major ion species in the upper ionospheres of both Earth and Mars is O⁺, and hence it is more likely to dominate the escape process. On Earth, due to a strong intrinsic magnetic field, the major ion outflow pathways are through the cusp, polar cap, and the auroral oval. In contrast, Mars has an induced magnetosphere, where the ionosphere is in direct contact with the shocked solar wind plasma. Therefore, physical processes underlying the ion energization and escape rates are expected to be different on Mars as compared to Earth. In the current work, we study the near-simultaneous ion outflow event from both Earth and Mars during the passage of a stream interaction region/high-speed stream (SIR/HSS) during 2016 May, when both the planets were approximately aligned on the same side of the Sun. The SIR/HSS propagation was recorded by spacecraft at the Sun–Earth L1 point and Mars Express at 1.5 au. During the passage of the SIR, the dayside and nightside ion outflows at Earth were observed by Van Allen Probes and Magnetospheric Multiscale Mission orbiters, respectively. At Mars, the ion energization at different altitudes was observed by the STATIC instrument on board the MAVEN orbiter. We observe evidence for the enhanced ion outflow from both Earth and Mars during the passage of the SIR, and identify the dominant drivers of the ion outflow. 

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4. The composition of Mars

   https://doi.org/doi:10.1016/j.gca.2020.01.011  

   Yoshizaki, Takashi; McDonough, William F. (March 2020, Geochimica et cosmochimica acta)

   Comparing compositional models of the terrestrial planets provides insights into physicochemical processes that produced planet-scale similarities and differences. The widely accepted compositional model for Mars assumes Mn and more refractory elements are in CI chondrite proportions in the planet, including Fe, Mg, and Si, which along with O make up >90% of the mass of Mars. However, recent improvements in our understandings on the composition of the solar photosphere and meteorites challenge the use of CI chondrite as an analog of Mars. Here we present an alternative model composition for Mars that avoids such an assumption and is based on data from Martian meteorites and spacecraft observations. Our modeling method was previously applied to predict the Earth’s composition. The model establishes the absolute abundances of refractory lithophile elements in the bulk silicate Mars (BSM) at 2.26 times higher than that in CI carbonaceous chondrites. Relative to this chondritic composition, Mars has a systematic depletion in moderately volatile lithophile elements as a function of their condensation temperatures. Given this finding, we constrain the abundances of siderophile and chalcophile elements in the bulkMars and its core. The Martian volatility trend is consistent with <7 wt% S in its core, which is significantly lower than that assumed in most core models (i.e., >10 wt% S). Furthermore, the occurrence of ringwoodite at the Martian core-mantle boundary might have contributed to the partitioning of O and H into the Martian core. 

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5. Comparative Analysis of Terahertz Propagation Under Dust Storm Conditions on Mars and Earth

   https://doi.org/10.1109/JSTSP.2023.3285450  

   Wedage, Lasantha Thakshila; Butler, Bernard; Balasubramaniam, Sasitharan; Koucheryavy, Yevgeni; Vuran, Mehmet C. (July 2023, IEEE Journal of Selected Topics in Signal Processing)

   Reliable Terahertz (THz) links are necessary for outdoor point-to-point communication with the exponential growth of wireless data traffic. This study presents a modified Monte Carlo simulation procedure for estimating THz link attenuation due to multiple scattering by charged dust particles on the THz beam propagation path. Scattering models are developed for beams through dust, based on Mie and Rayleigh approximations for corresponding frequencies on Earth (0.24 THz) and Mars (0.24 & 1.64 THz). The simulation results are compared, considering parameters such as the number of Monte-Carlo photon (MCP) packets, visibility, dust particle placement density along the beam, frequency, and distance between the transmitter and the receiver. Moreover, a channel capacity model was proposed, considering THz link attenuation due to dust storms, spreading loss, and molecular absorption loss for Earth and Mars outdoor environments. Simulation results for Earth show that the link attenuation increases with dust particle placement density, distance, and frequency, and attenuation decreases with visibility and MCP packets. On Mars, similar results are obtained for both frequencies, except that the attenuation varies around a constant value with the frequency increase. Moreover, attenuation is slightly higher at 0.24 THz frequency compared to 1.64 THz when more dust particles are present on the beam propagation path. Channel capacity is estimated for Earth and Mars environments considering time and distance-dependent scenarios. Time windows that show a sudden drop of dust particles along the beam provide opportunities to communicate with high reliability. Moreover, increasing the distance between the transmitter and receiver severely reduces the channel capacity measurement in strong dust storm conditions in both environments. Our study has found that weak dust storms have relatively little effect on Mars but much more significant effects on Earth. 

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