Wind‐formed features are abundant in Oxia Planum (Mars), the landing site of the 2022 ExoMars mission, which shows geological evidence for a past wet environment. Studies of aeolian bedforms at the ...landing site were focused on assessing the risk for rover trafficability, however their potential in recording climatic fluctuations has not been explored. Here we show that the landing site experienced multiple climatic changes in the Amazonian, which are recorded by an intriguing set of ridges that we interpret as Periodic Bedrock Ridges (PBRs). Clues for a PBR origin result from ridge regularity, defect terminations, and the presence of preserved megaripples detaching from the PBRs. PBR orientation differs from superimposed transverse aeolian ridges pointing toward a major change in wind regime. Our results provide constrains on PBR formation mechanisms and offer indications on paleo winds that will be crucial for understanding the landing site geology.
Plain Language Summary
Oxia Planum on Mars is the landing site for the ExoMars 2022 mission. The region likely hosted a standing body of water, but the effect of the wind was also important in shaping the landscape. In this study, we first describe a set of linear ridges that, in our interpretation, were sculpted by the wind in a more recent past. We also show that the wind that formed the ridges (Periodic Bedrock Ridges) was blowing from a different direction than the ones that formed younger ripples on top, suggesting a complex geological history of wind erosion and deposition that will be further investigated during the ExoMars mission.
Key Points
We present the first evidence for a periodic bedrock ridge (PBRs) pattern from the ExoMars 2022 landing site
Formative paleowind directions are extrapolated from PBRs and transverse aeolian ridges
Evidence for an Amazonian change in the wind regime are provided
The paper deals with a microsatellite and the related deployable recovery capsule. The aero-brake is folded at launch and deployed in space and is able to perform a de-orbiting controlled re-entry. ...This kind of capsule, with a flexible, high temperature resistant fabric, thanks to its lightness and modulating capability, can be an alternative to the current “conventional” recovery capsules. The present authors already analyzed the trajectory and the aerodynamic behavior of low ballistic coefficient capsules during Earth re-entry and Mars entry. In previous studies, aerodynamic longitudinal stability analysis and evaluation of thermal and aerodynamic loads for a possible suborbital re-entry demonstrator were carried out in both continuum and rarefied regimes. The present study is aimed at providing preliminary information about thermal and aerodynamic loads and longitudinal stability for a similar deployable capsule, as well as information about the electronic composition of the plasma sheet and its possible influence on radio communications at the altitudes where GPS black-out could occur. Since the computer tests were carried out at high altitudes, therefore in rarefied flow fields, use of Direct Simulation Monte Carlo codes was mandatory. The computations involved both global aerodynamic quantities (drag and longitudinal moment coefficients) and local aerodynamic quantities (heat flux and pressure distributions along the capsule surface). The results verified that the capsule at high altitude (150km) is self-stabilizing; it is stable around the nominal attitude or at zero angle of attack and unstable around the reverse attitude or at 180° angle of attack. The analysis also pointed out the presence of extra statically stable equilibrium trim points.
•Longitudinal stability of a small deployable capsule during the Earth re-entry.•Altitude interval where the GPS black-out could occur.•Computations carried out by means of two DSMC codes: DS3V, DS2V.
The aim of this work is to describe the development and implementation of an experimental setup able to reproduce some characteristics of the Martian atmosphere. The development of such setup fits ...into the context of MicroMED project, that foresees the development of an optical particle counter to be accommodated on the ExoMars 2020 Surface Platform, as part of the suite of sensors named Dust Complex. MicroMED will perform the first direct measurement of the size distribution of the powder close to Martian surface. The experimental setup is able to reproduce the characteristics of the Martian atmosphere: pressure, atmospheric composition, the actual temperature in which MicroMED will operate (from −20 °C to 40 °C) and the most important thing: the presence of suspended dust.
The main result obtained in this work was the right configuration of an experimental setup in which to test sensors or instruments that work in Martian conditions. In particular, a dust injection system has been developed in order to obtain a dust distribution that was localized and without the formation of particles aggregates, for a correct calibration of the instrument.
•Having developed an experimental setup capable of reproducing some Martian weather conditions like atmospheric composition, presence of dust and pressure.•Having developed a functional powder injection system for the calibration of a Martian optical particle counter.•Use of ethanol to minimize the triboelectric effects of the grains injected into the simulation chamber and consequently to have drastically reduced the formation of dust aggregates.•Possibility of injecting powder in different ways according to the needs.•Tests on the first breadboard version of an optical particles counter capable of operating in Martian weather conditions.
The Dust Complex (DC) instrument was designed to be installed on the landing platform of the ExoMars project. The purpose of the experiment is to study the dynamics of dust particles in the ...near-surface atmosphere of Mars and to evaluate the main characteristics of the near-surface medium that determine their dynamics. The device makes it possible to register dust particles in the near-surface atmosphere of Mars, determine the main parameters and measure some characteristics of the plasma-dust medium related to the dynamics of dust particles near the Martian surface. The article provides a description of the device, its blocks and sensors, the main elements of the measurement program and characteristics of the measured parameters.
Prolonged human-crewed missions on the Moon are foreseen as a gateway for Mars and asteroid colonisation in the next decades. Health risks related to long-time permanence in space have been partially ...investigated. Hazards due to airborne biological contaminants represent a relevant problem in space missions. A possible way to perform pathogens' inactivation is by employing the shortest wavelength range of Solar ultraviolet radiation, the so-called germicidal range. On Earth, it is totally absorbed by the atmosphere and does not reach the surface. In space, such Ultraviolet solar component is present and effective germicidal irradiation for airborne pathogens' inactivation can be achieved inside habitable outposts through a combination of highly reflective internal coating and optimised geometry of the air ducts. The Solar Ultraviolet Light Collector for Germicidal Irradiation on the Moon is a project whose aim is to collect Ultraviolet solar radiation and use it as a source to disinfect the re-circulating air of the human outposts. The most favourable positions where to place these collectors are over the peaks at the Moon's poles, which have the peculiarity of being exposed to solar radiation most of the time. On August 2022, NASA communicated to have identified 13 candidate landing regions near the lunar South Pole for Artemis missions. Another advantage of the Moon is its low inclination to the ecliptic, which maintains the Sun's apparent altitude inside a reduced angular range. For this reason, Ultraviolet solar radiation can be collected through a simplified Sun's tracking collector or even a static collector and used to disinfect the recycled air. Fluid-dynamic and optical simulations have been performed to support the proposed idea. The expected inactivation rates for some airborne pathogens, either common or found on the International Space Station, are reported and compared with the proposed device efficiency. The results show that it is possible to use Ultraviolet solar radiation directly for air disinfection inside the lunar outposts and deliver a healthy living environment to the astronauts.
Study objective We assess hospital readmission and death within 60 days in older adults admitted from the emergency department (ED) and discharged by an inpatient service within 24 hours. Methods ...This was a retrospective review of ED patients aged 64 years or older, admitted from 2 hospitals (2004 to 2006), who were discharged home within 24 hours. Excluded were inhospital deaths, observation admissions, transfers to other facilities, patients who left against medical advice, and hospice patients. Outcomes were 72-hour and 30-day readmissions and postdischarge deaths that occurred within 60 days of ED admission. Logistic regression was used to assess for predictors of readmission. A chart review of deaths after discharge was performed to assess for potential contributors to adverse outcomes. Results A total of 1,470 admissions met inclusion criteria as 1-day admissions. Of those, 22 (1.5%) patients returned for hospital readmission within 72 hours and 156 (10.6%) within 30 days of discharge. In the multivariable analysis, previous admissions (odds ratio OR 1.3; 95% confidence interval CI 1.1 to 1.4) and an admission diagnosis of heart failure (OR 2.2; 95% CI 1.0 to 5.0) were associated with 30-day readmission. In 841 individual patients with greater than or equal to one 1-day admission, there were 15 deaths (1.8%) within 60 days. Of those, 11 (73%) patients had abnormal ED ECG results, 6 (40%) were ruled out for acute myocardial infarction while hospitalized, and 3 (20%) had definitive follow-up arranged at discharge. Conclusion One-day admissions in hospitalized older adults through the ED do not represent a group at low risk for postdischarge adverse outcomes.
The assembly of the approximately 1700 LHC main ring cryostats at CERN involved extensive welding of cryogenic lines and vacuum vessels. More than 6 km of welding requiring leak tightness to a rate ...better than 1.10-9 mbar*l*s-1 on stainless steel and aluminium piping and envelopes was made, essentially by manual welding but also making use of orbital welding machines. In order to fulfill the safety regulations related to pressure vessels and to comply with the leak-tightness requirements of the vacuum systems of the machine, welds were executed according to high qualification standards and following a severe quality assurance plan. Leak detection by He mass spectrometry was extensively used. Neon leak detection was used successfully to locate leaks in the presence of helium backgrounds.This paper presents the quality assurance strategy adopted for welds and leak detection. It presents the statistics of non-conformities on welds and leaks detected throughout the entire production and the advances in the use of alternative leak detection methods in an industrial environment.
SAILOR Moon is a concept air sanitiser for closed space environments. There is indeed an increasing interest in the development of potentially inhabited outposts in space, such as the forecasted ...NASA's Lunar Gateway, as well as on the Moon and Mars surfaces. The health monitoring of astronauts is paramount in the development of such missions. The idea is to collect pathogens emitted in the closed environment by astronauts, especially through bioaerosol, and use the well-known principle of Ultraviolet Germicidal Irradiation (UVGI) through UVC light for pathogen inactivation. This work focuses on the method for predicting the device's bioaerosol dynamics. The method mainly relies on Computational Fluid Dynamics (CFD) and optical simulations. In this paper, the CFD simulations performed are presented, along with some analysis results and their implications.
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