United Kingdom Space Agency

This study presents a large-scale mapping framework for identifying and characterizing periodic decameter aeolian landforms on Mars using CTX mosaics and machine learning. To test whether the mapped features align with the current aeolian regime, we mapped barchan slipfaces and used Global Climate Model (GCM) outputs to characterize present-day aeolian activity across an extended region, encompassing the Thaumasia and Bosporos planae as well as the lowlands located in the northwestern edge of Noachis Terra. Morphology and data clustering allowed us to define eight regional units, presenting distinct sets of aeolian landforms. The spatial distribution of these units is influenced by long-wavelength topography, with the Thaumasia highlands and Coprates rise forming a major divide. The bedforms in Thaumasia and Bosporos planae are morphologically simpler and possibly younger. Yet, their trend deviates by 35° from the orientation of GCM-predicted bedforms forming under current surface conditions. In addition, the units located in the eastern lowlands display complex morphologies and paleo-wind streaks indicative of multi-phase aeolian imprints. These features imply an ancient SE-NW paleo-wind regime, opposing the current southeastward transport trend. These major discrepancies may reflect several reorganizations of Mars’ atmospheric circulation in the past. Our systematic mapping results underscore the richness and complexity of Mars’ aeolian record, revealing extensive and continuous patches of likely ancient wind-shaped landforms. Our results suggest that a considerable number of multi-generational aeolian imprints (i.e. wind-formed features created over multiple periods) may have been preserved on the surface of Mars, under the form of decameter-scale aeolian landforms.

In this study, we analyze the surface aeolian record around the Coprates rise region, an extensive area that includes Thaumasia and Bosporos Planae as well as the western Noachis Terra lowlands. The main goals are: a) to test the systematic mapping of aeolian bedforms (PBRs, TARs, and/or paleo-megaripples ) at medium resolutions using CTX mosaics and the techniques introduced by Vaz et al. ( 2023); b) to evaluate the spatial distribution of aeolian bedforms and identify different populations in this large area; c) to use GCM predictions and state-of-the-art bedform formation models to test how well the mapped features fit the predicted current-day surface aeolian dynamics.  The automated methodology accurately maps various sets of linear and periodic bedforms. We estimate that about 50% of the mapped bedforms are associated with or controlled by local topography, showing clear spatial associations with specific topographic settings: craters, incised valleys, grabens and wrinkle ridges. These were excluded from a comparative analysis with the GCM-derived predictions. We identified eight sets of bedforms with very different characteristics (e.g. trends, wavelength, morphologies, and preservation state). We found significant disparities between the mapped bedform trends and the GCM-based predictions, suggesting that most of the mapped sets are incompatible with current surface aeolian dynamics, as predicted from the GCM outputs.  ReferencesVaz, D. A., Silvestro, S., Chojnacki, M., & Silva, D. C. A. (2023). Constraining the mechanisms of aeolian bedform formation on Mars through a global morphometric survey. Earth and Planetary Science Letters, 614, 118196. https://doi.org/10.1016/j.epsl.2023.11819

This paper aims to study the feasibility of applying deep learning techniques in the geospatial application domain. Two geospatial projects were economically analysed. The first project was to produce land use maps from satellite imagery for the current and past years using three machine learning algorithms. Based on the produced historical maps, scenario predictions of the land use maps were generated [1]. The second geospatial project used a deep learning object detection technique to count the total numbers of palm trees automatically and develop a geospatial database that has the exact coordinate location per each palm tree distributed in the Kingdom of Bahrain [2]. The technical, administrative, and financial costs were identified as well as the benefit in the monetary value per each project. As a result, benefit-cost analysis was conducted to evaluate both projects economically.

It is a difficult project to tackle, in a book – the subject of exoplanets – as it is one of the fastest-moving branches of planetary science. In The Planet Factory Elizabeth Tasker, an astrophysicist at Japan's JAXA space agency, has bravely taken on the role of navigator for this incredible journey of planetary discovery, and the book does not disappoint.

Tissint (Morocco) is the fifth martian meteorite collected after it was witnessed falling to Earth. Our integrated mineralogical, petrological, and geochemical study shows that it is a depleted picritic shergottite similar to EETA79001A. Highly magnesian olivine and abundant glass containing martian atmosphere are present in Tissint. Refractory trace element, sulfur, and fluorine data for the matrix and glass veins in the meteorite indicate the presence of a martian surface component. Thus, the influence of in situ martian weathering can be unambiguously distinguished from terrestrial contamination in this meteorite. Martian weathering features in Tissint are compatible with the results of spacecraft observations of Mars. Tissint has a cosmic-ray exposure age of 0.7 ± 0.3 million years, consistent with those of many other shergottites, notably EETA79001, suggesting that they were ejected from Mars during the same event.

The Cosmic Radiation Environment and Dosimetry experiment was built to accompany the CRUX (Cosmic Ray Upset) experiment on the USAF APEX satellite, launched in August 1994. Results of measurements of the space radiation environment are presented.

The overall launch mass of a communications satellite has a major influence on its economic performance. If this mass can be reduced substantially, the launch cost will be lower, or more revenue can be generated by carrying a larger payload or extending the operational lifetime. Since an ion propulsion system provides an exhaust velocity at least an order of magnitude higher than that of chemical thrusters, the propellant mass required for north–south station-keeping can be reduced by hundreds of kilogrammes, thereby gaining these benefits. This application of ion propulsion is discussed and quantified in the paper, for the Intelsat VII spacecraft and the UK-10 ion propulsion system.