Atmosphere Assessment for MARS Science Laboratory Entry, Descent and Landing Operations

On August 6, 2012, the Mars Science Laboratory rover, Curiosity, successfully landed on the surface of Mars. The Entry, Descent and Landing (EDL) sequence was designed using atmospheric conditions estimated from mesoscale numerical models. The models, developed by two independent organizations (Oregon State University and the Southwest Research Institute), were validated against observations at Mars from three prior years. In the weeks and days before entry, the MSL "Council of Atmospheres" (CoA), a group of atmospheric scientists and modelers, instrument experts and EDL simulation engineers, evaluated the latest Mars data from orbiting assets including the Mars Reconnaissance Orbiter's Mars Color Imager (MARCI) and Mars Climate Sounder (MCS), as well as Mars Odyssey's Thermal Emission Imaging System (THEMIS). The observations were compared to the mesoscale models developed for EDL performance simulation to determine if a spacecraft parameter update was necessary prior to entry. This paper summarizes the daily atmosphere observations and comparison to the performance simulation atmosphere models. Options to modify the atmosphere model in the simulation to compensate for atmosphere effects are also presented. Finally, a summary of the CoA decisions and recommendations to the MSL project in the days leading up to EDL is provided

Promised incentives on a random digit dial survey

Die Verfasser legen die Ergebnisse von zwei Experimenten vor, mit denen die Wirkung von versprochenen Belohnungen bei einer Random-Digit-Dial-Untersuchung im Stadium der Gesprächseröffnung sowie im Stadium der Aufgabe einer anfänglichen Verweigerungshaltung untersucht werden sollte. In beiden Fällen zeigte sich kein Effekt. Dieses Ergebnis steht im Widerspruch zu mindestens einem weiteren Experiment aus jüngster Zeit sowie auch zum Einsatz versprochener Belohnungen zur Reduktion von Antwortverweigerung bei mehreren Meinungsforschungsinstituten. Die Verfasser diskutieren mögliche Ursachen für das Ausbleiben eines Effekts. (ICEÜbers)"This paper presents the results of two experiments carried out to test the effectiveness of promised incentives for a random digit dial survey (RDD) at the initial household contact (introduction) and at the stage of refusal conversion. The results of the experiments find no effect of at either stage of the survey process. These results are contrary to those found by at least one other recent experiment, as well as the use of promised incentives used routinely to convert reluctant respondents by several survey organizations. The possible reasons for not finding an effect are discussed." (author's abstract

Dust aerosol, clouds, and the atmospheric optical depth record over 5 Mars years of the Mars Exploration Rover mission

Dust aerosol plays a fundamental role in the behavior and evolution of the Martian atmosphere. The first five Mars years of Mars Exploration Rover data provide an unprecedented record of the dust load at two sites. This record is useful for characterization of the atmosphere at the sites and as ground truth for orbital observations. Atmospheric extinction optical depths have been derived from solar images after calibration and correction for time-varying dust that has accumulated on the camera windows. The record includes local, regional, and globally extensive dust storms. Comparison with contemporaneous thermal infrared data suggests significant variation in the size of the dust aerosols, with a 1 {\mu}m effective radius during northern summer and a 2 {\mu}m effective radius at the onset of a dust lifting event. The solar longitude (LS) 20-136{\deg} period is also characterized by the presence of cirriform clouds at the Opportunity site, especially near LS=50 and 115{\deg}. In addition to water ice clouds, a water ice haze may also be present, and carbon dioxide clouds may be present early in the season. Variations in dust opacity are important to the energy balance of each site, and work with seasonal variations in insolation to control dust devil frequency at the Spirit site.Comment: 60 pages, 12 figures, to be published in Icaru

Emission of non‐thermal microwave radiation by a Martian dust storm

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94934/1/grl26053.pd

The Earned Income Tax Credit and Food Consumption Patterns

The Earned Income Tax Credit is unique among social programs in that benefits are not paid out evenly across the calendar year. We exploit this feature of the EITC to investigate how the credit influences the food expenditure patterns of eligible households. We find that eligible households spend relatively more on healthy items including fresh fruit and vegetables, meat and poultry, and dairy products during the months when most refunds are paid

Pre- and Post-entry, Descent and Landing Assessment of the Martian Atmosphere for the Mars 2020 Rover

This review provides an analysis of activities undertaken by the Mars 2020 Council of Atmospheres (CoA) in support of the entry, descent, and landing (EDL) of the Mars 2020 rover Perseverance in Jezero crater, Mars. The activities of the CoA were designed to evaluate the safety of early-stage landing site candidates and, later, to constrain the range of plausible conditions expected at Jezero crater during the early northern spring season of EDL, following the successful blueprint of similar councils for prior landed Mars missions. The multiyear effort of the CoA involved using a combination of numerical modeling of the local Martian atmosphere with limited-domain mesoscale models and atmospheric reanalysis using data assimilation techniques, along with atmospheric observations from multiple orbiting assets, to generate an atmospheric “forecast” for the day of landing. Here we present an overview of these activities, focusing in greater detail on those elements that depart from prior CoA activities as performed for Mars Phoenix, Mars Science Laboratory, and the InSight lander. Following the successful landing of Perseverance on 2021 February 18, reconstruction and reassessment activities were performed and are presented here, comparing prelanding predictions with actual, as-flown conditions

Intravital Observation of Plasmodium berghei Sporozoite Infection of the Liver

Plasmodium sporozoite invasion of liver cells has been an extremely elusive event to study. In the prevailing model, sporozoites enter the liver by passing through Kupffer cells, but this model was based solely on incidental observations in fixed specimens and on biochemical and physiological data. To obtain direct information on the dynamics of sporozoite infection of the liver, we infected live mice with red or green fluorescent Plasmodium berghei sporozoites and monitored their behavior using intravital microscopy. Digital recordings show that sporozoites entering a liver lobule abruptly adhere to the sinusoidal cell layer, suggesting a high-affinity interaction. They glide along the sinusoid, with or against the bloodstream, to a Kupffer cell, and, by slowly pushing through a constriction, traverse across the space of Disse. Once inside the liver parenchyma, sporozoites move rapidly for many minutes, traversing several hepatocytes, until ultimately settling within a final one. Migration damage to hepatocytes was confirmed in liver sections, revealing clusters of necrotic hepatocytes adjacent to structurally intact, sporozoite-infected hepatocytes, and by elevated serum alanine aminotransferase activity. In summary, malaria sporozoites bind tightly to the sinusoidal cell layer, cross Kupffer cells, and leave behind a trail of dead hepatocytes when migrating to their final destination in the liver

Mosaic: A Satellite Constellation to Enable Groundbreaking Mars Climate System Science and Prepare for Human Exploration

The Martian climate system has been revealed to rival the complexity of Earth\u27s. Over the last 20 yr, a fragmented and incomplete picture has emerged of its structure and variability; we remain largely ignorant of many of the physical processes driving matter and energy flow between and within Mars\u27 diverse climate domains. Mars Orbiters for Surface, Atmosphere, and Ionosphere Connections (MOSAIC) is a constellation of ten platforms focused on understanding these climate connections, with orbits and instruments tailored to observe the Martian climate system from three complementary perspectives. First, low-circular near-polar Sun-synchronous orbits (a large mothership and three smallsats spaced in local time) enable vertical profiling of wind, aerosols, water, and temperature, as well as mapping of surface and subsurface ice. Second, elliptical orbits sampling all of Mars\u27 plasma regions enable multipoint measurements necessary to understand mass/energy transport and ion-driven escape, also enabling, with the polar orbiters, dense radio occultation coverage. Last, longitudinally spaced areostationary orbits enable synoptic views of the lower atmosphere necessary to understand global and mesoscale dynamics, global views of the hydrogen and oxygen exospheres, and upstream measurements of space weather conditions. MOSAIC will characterize climate system variability diurnally and seasonally, on meso-, regional, and global scales, targeting the shallow subsurface all the way out to the solar wind, making many first-of-their-kind measurements. Importantly, these measurements will also prepare for human exploration and habitation of Mars by providing water resource prospecting, operational forecasting of dust and radiation hazards, and ionospheric communication/positioning disruptions