InSight Pressure Data Recalibration, and Its Application to the Study of Long-Term Pressure Changes on Mars

Observations of the South Polar Residual Cap suggest a possible erosion of the cap, leading to an increase of the global mass of the atmosphere. We test this assumption by making the first comparison between Viking 1 and InSight surface pressure data, which were recorded 40 years apart. Such a comparison also allows us to determine changes in the dynamics of the seasonal ice caps between these two periods. To do so, we first had to recalibrate the InSight pressure data because of their unexpected sensitivity to the sensor temperature. Then, we had to design a procedure to compare distant pressure measurements. We propose two surface pressure interpolation methods at the local and global scale to do the comparison. The comparison of Viking and InSight seasonal surface pressure variations does not show changes larger than ±8 Pa in the CO₂ cycle. Such conclusions are supported by an analysis of Mars Science Laboratory (MSL) pressure data. Further comparisons with images of the south seasonal cap taken by the Viking 2 orbiter and MARCI camera do not display significant changes in the dynamics of this cap over a 40 year period. Only a possible larger extension of the North Cap after the global storm of MY 34 is observed, but the physical mechanisms behind this anomaly are not well determined. Finally, the first comparison of MSL and InSight pressure data suggests a pressure deficit at Gale crater during southern summer, possibly resulting from a large presence of dust suspended within the crater.

The Emirates Mars Mission

The Emirates Mars Mission (EMM) was launched to Mars in the summer of 2020, and is the first interplanetary spacecraft mission undertaken by the United Arab Emirates (UAE). The mission has multiple programmatic and scientific objectives, including the return of scientifically useful information about Mars. Three science instruments on the mission's Hope Probe will make global remote sensing measurements of the Martian atmosphere from a large low-inclination orbit that will advance our understanding of atmospheric variability on daily and seasonal timescales, as well as vertical atmospheric transport and escape. The mission was conceived and developed rapidly starting in 2014, and had aggressive schedule and cost constraints that drove the design and implementation of a new spacecraft bus. A team of Emirati and American engineers worked across two continents to complete a fully functional and tested spacecraft and bring it to the launchpad in the middle of a global pandemic. EMM is being operated from the UAE and the United States (U.S.), and will make its data freely available.

Multi-model Meteorological and Aeolian Predictions for Mars 2020 and the Jezero Crater Region

Nine simulations are used to predict the meteorology and aeolian activity of the Mars 2020 landing site region. Predicted seasonal variations of pressure and surface and atmospheric temperature generally agree. Minimum and maximum pressure is predicted at Ls ∼ 145 ∘ and 250 ∘ , respectively. Maximum and minimum surface and atmospheric temperature are predicted at Ls ∼ 180 ∘ and 270 ∘ , respectively; i.e., are warmest at northern fall equinox not summer solstice. Daily pressure cycles vary more between simulations, possibly due to differences in atmospheric dust distributions. Jezero crater sits inside and close to the NW rim of the huge Isidis basin, whose daytime upslope (∼east-southeasterly) and nighttime downslope (∼northwesterly) winds are predicted to dominate except around summer solstice, when the global circulation produces more southerly wind directions. Wind predictions vary hugely, with annual maximum speeds varying from 11 to 19 ms - 1 and daily mean wind speeds peaking in the first half of summer for most simulations but in the second half of the year for two. Most simulations predict net annual sand transport toward the WNW, which is generally consistent with aeolian observations, and peak sand fluxes in the first half of summer, with the weakest fluxes around winter solstice due to opposition between the global circulation and daytime upslope winds. However, one simulation predicts transport toward the NW, while another predicts fluxes peaking later and transport toward the WSW. Vortex activity is predicted to peak in summer and dip around winter solstice, and to be greater than at InSight and much greater than in Gale crater.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11214-020-00788-2.

The paradoxes of the Late Hesperian Mars ocean

The long-standing debate on the existence of ancient oceans on Mars has been recently revived by evidence for tsunami resurfacing events that date from the Late Hesperian geological era. It has been argued that these tsunami events originated from the impact of large meteorites on a deglaciated or nearly deglaciated ocean present in the northern hemisphere of Mars. Here we show that the presence of such a late ocean faces a paradox. If cold, the ocean should have been entirely frozen shortly after its formation, thus preventing the formation of tsunami events. If warm, the ice-free ocean should have produced fluvial erosion of Hesperian Mars terrains much more extensively than previously reported. To solve this apparent paradox, we suggest a list of possible tests and scenarios that could help to reconcile constraints from climate models with tsunami hypothesis. These scenarios could be tested in future dedicated studies.

Abstract PD1-09: Phase 2 safety and efficacy results of TAK-228 in combination with exemestane or fulvestrant in postmenopausal women with ER-positive/HER2-negative metastatic breast cancer previously treated with everolimus

Background: TAK-228 is an investigational, oral and highly selective ATP-competitive inhibitor of TORC1/2. Targeting the PI3K/AKT/mTOR pathway with the dual TORC1/2 inhibitor TAK-228 may restore sensitivity to endocrine therapies in patients (pts) with breast cancer who have progressed on the combination of an endocrine agent plus a TORC1 inhibitor. Here we report data from the phase 2 portion of a phase 1b/2 study of TAK-228 plus exemestane (E) or fulvestrant (F).

Methods: Postmenopausal women with ER+ and HER2-, inoperable or metastatic breast cancer (MBC) following everolimus (EVE) plus E or F after progression, received oral TAK-228 (4 mg QD) plus E (25 mg QD) or F (500 mg monthly) for 28-day cycles until progressive disease (PD) or unacceptable toxicity (NCT02049957). Pts were enrolled into parallel cohorts based on prior response to EVE plus E or F and were given the same prior therapy (E or F) at their established dose: EVE-sensitive, defined as disease progression after complete response (CR), partial response (PR), or ≥6 mos stable disease (SD); or EVE-resistant, defined as disease progression without a CR or PR, or after <6 mos SD. Primary endpoint was clinical benefit rate at 16 wks (CR, PR, or SD at 16 wks; CBR-16). Secondary endpoints included CBR at 24 wks (CBR-24), overall response rate (ORR), progression-free survival (PFS), overall survival (OS) and safety.

Results: From Oct 2015 to Dec 2017, 94 pts were enrolled. Median age was 58 y (range 32–83). At baseline, most pts (67%) had stage IV disease and others were stage IA–IIIC (24%), other (3%) or unknown (5%); 94% of EVE-sensitive (93% E vs 100% F) and 88% of EVE-resistant pts (91% E vs 75% F) had received ≥4 prior lines of therapy. Pts received a median of 3 cycles (1–15) of TAK-228. At data cutoff (24 Apr 2018), 98% of pts had discontinued treatment, mainly due to PD (76%) or adverse events (AEs; 14%). CBR-16 was 41% (n=21) in EVE-sensitive and 26% (n=11) in EVE-resistant pts (table). CBR-24 was 24% in EVE-sensitive (19% E vs 50% F) and 23% in EVE-resistant (23% E vs 25% F) pts. Eleven of 21 pts who achieved CBR-16 also achieved CBR-24 (6 SD, 5 PR) in the EVE-sensitive cohort and 8 of 11 pts in the EVE-resistant cohort (6 SD, 2 PR). The ORR was 12% in EVE-sensitive pts and 9% in EVE-resistant pts (table). Median PFS (95% CI) was 4.1 mos (2.2–5.5) and 3.4 mos (1.9–5.4), and median OS (95% CI) was 15.9 mos (14.1–19.5) and 14.0 mos (13.0–16.0) in the EVE-sensitive and -resistant cohorts, respectively. Drug-related any grade and grade ≥3 AEs were seen in 90% and 29% of pts, respectively. Most common drug-related any grade AEs were nausea (50%), fatigue (38%), hyperglycemia and diarrhea (each 29%); 22% of pts reported a serious AE. No deaths were reported. Treatment is ongoing in two pts.

Conclusion: TAK-228 plus E or F showed modest clinical benefit in pts with previously treated, EVE-sensitive or -resistant MBC, with an acceptable safety profile.

 EVE-sensitive (N=51)EVE-resistant (N=43) TAK-228+TAK-228+Best response, n (%)E (n=43)F (n=8)E (n=35)F (n=8)ORR=CR+PR4 (9)2 (25)3 (9)1 (13)CR001 (3)0PR4 (9)2 (25)2 (6)1 (13)CBR-1617 (40)4 (50)9 (26)2 (25)

Citation Format: Diamond JR, Potter D, Salkeni M, Silverman P, Haddad T, Forget F, Awada A, Canon J-L, Danso M, Lortholary A, Bourgeois H, Tan-Chiu E, Patel C, Neuwirth R, Leonard EJ, Lim B. Phase 2 safety and efficacy results of TAK-228 in combination with exemestane or fulvestrant in postmenopausal women with ER-positive/HER2-negative metastatic breast cancer previously treated with everolimus [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD1-09.

Possible climates on terrestrial exoplanets

What kind of environment may exist on terrestrial planets around other stars? In spite of the lack of direct observations, it may not be premature to speculate on exoplanetary climates, for instance, to optimize future telescopic observations or to assess the probability of habitable worlds. To begin with, climate primarily depends on (i) the atmospheric composition and the volatile inventory; (ii) the incident stellar flux; and (iii) the tidal evolution of the planetary spin, which can notably lock a planet with a permanent night side. The atmospheric composition and mass depends on complex processes, which are difficult to model: origins of volatiles, atmospheric escape, geochemistry, photochemistry, etc. We discuss physical constraints, which can help us to speculate on the possible type of atmosphere, depending on the planet size, its final distance for its star and the star type. Assuming that the atmosphere is known, the possible climates can be explored using global climate models analogous to the ones developed to simulate the Earth as well as the other telluric atmospheres in the solar system. Our experience with Mars, Titan and Venus suggests that realistic climate simulators can be developed by combining components, such as a 'dynamical core', a radiative transfer solver, a parametrization of subgrid-scale turbulence and convection, a thermal ground model and a volatile phase change code. On this basis, we can aspire to build reliable climate predictors for exoplanets. However, whatever the accuracy of the models, predicting the actual climate regime on a specific planet will remain challenging because climate systems are affected by strong positive feedbacks. They can drive planets with very similar forcing and volatile inventory to completely different states. For instance, the coupling among temperature, volatile phase changes and radiative properties results in instabilities, such as runaway glaciations and runaway greenhouse effect.

Mars environment and magnetic orbiter scientific and measurement objectives

In this paper, we summarize our present understanding of Mars' atmosphere, magnetic field, and surface and address past evolution of these features. Key scientific questions concerning Mars' surface, atmosphere, and magnetic field, along with the planet's interaction with solar wind, are discussed. We also define what key parameters and measurements should be performed and the main characteristics of a martian mission that would help to provide answers to these questions. Such a mission--Mars Environment and Magnetic Orbiter (MEMO)--was proposed as an answer to the Cosmic Vision Call of Opportunity as an M-class mission (corresponding to a total European Space Agency cost of less than 300 Meuro). MEMO was designed to study the strong interconnection between the planetary interior, atmosphere, and solar conditions, which is essential to our understanding of planetary evolution, the appearance of life, and its sustainability. The MEMO main platform combined remote sensing and in situ measurements of the atmosphere and the magnetic field during regular incursions into the martian upper atmosphere. The micro-satellite was designed to perform simultaneous in situ solar wind measurements. MEMO was defined to conduct: * Four-dimensional mapping of the martian atmosphere from the surface up to 120 km by measuring wind, temperature, water, and composition, all of which would provide a complete view of the martian climate and photochemical system; Mapping of the low-altitude magnetic field with unprecedented geographical, altitude, local time, and seasonal resolutions; A characterization of the simultaneous responses of the atmosphere, magnetic field, and near-Mars space to solar variability by means of in situ atmospheric and solar wind measurements.

A warm layer in Venus' cryosphere and high-altitude measurements of HF, HCl, H2O and HDO

Venus has thick clouds of H2SO4 aerosol particles extending from altitudes of 40 to 60 km. The 60-100 km region (the mesosphere) is a transition region between the 4 day retrograde superrotation at the top of the thick clouds and the solar-antisolar circulation in the thermosphere (above 100 km), which has upwelling over the subsolar point and transport to the nightside. The mesosphere has a light haze of variable optical thickness, with CO, SO2, HCl, HF, H2O and HDO as the most important minor gaseous constituents, but the vertical distribution of the haze and molecules is poorly known because previous descent probes began their measurements at or below 60 km. Here we report the detection of an extensive layer of warm air at altitudes 90-120 km on the night side that we interpret as the result of adiabatic heating during air subsidence. Such a strong temperature inversion was not expected, because the night side of Venus was otherwise so cold that it was named the 'cryosphere' above 100 km. We also measured the mesospheric distributions of HF, HCl, H2O and HDO. HCl is less abundant than reported 40 years ago. HDO/H2O is enhanced by a factor of approximately 2.5 with respect to the lower atmosphere, and there is a general depletion of H2O around 80-90 km for which we have no explanation.

No signature of clear CO2 ice from the ‘cryptic’ regions in Mars' south seasonal polar cap

The seasonal polar ice caps of Mars are composed mainly of CO2 ice. A region of low (< 30%) albedo has been observed within the south seasonal cap during early to mid-spring. The low temperature of this 'cryptic region' has been attributed to a clear slab of nearly pure CO2 ice, with the low albedo resulting from absorption by the underlying surface. Here we report near-infrared imaging spectroscopy of the south seasonal cap. The deep and broad CO2 absorption bands that are expected in the near-infrared with a thick transparent slab of CO2 ice are not observed. Models of the observed spectra indicate that the low albedo results from extensive dust contamination close to the surface of a CO2 ice layer, which could be linked to atmospheric circulation patterns. The strength of the CO2 absorption increases after mid-spring, so part of the dust is either carried away or buried more deeply in the ice layer during the CO2 ice sublimation process.

Global Mineralogical and Aqueous Mars History Derived from OMEGA/Mars Express Data

Global mineralogical mapping of Mars by the Observatoire pour la Mineralogie, l'Eau, les Glaces et l'Activité (OMEGA) instrument on the European Space Agency's Mars Express spacecraft provides new information on Mars' geological and climatic history. Phyllosilicates formed by aqueous alteration very early in the planet's history (the "phyllocian" era) are found in the oldest terrains; sulfates were formed in a second era (the "theiikian" era) in an acidic environment. Beginning about 3.5 billion years ago, the last era (the "siderikian") is dominated by the formation of anhydrous ferric oxides in a slow superficial weathering, without liquid water playing a major role across the planet.

Formation of Glaciers on Mars by Atmospheric Precipitation at High Obliquity

Surface conditions on Mars are currently cold and dry, with water ice unstable on the surface except near the poles. However, geologically recent glacierlike landforms have been identified in the tropics and the midlatitudes of Mars. The ice has been proposed to originate from either a subsurface reservoir or the atmosphere. We present high-resolution climate simulations performed with a model designed to simulate the present-day Mars water cycle but assuming a 45° obliquity as experienced by Mars a few million years ago. The model predicts ice accumulation in regions where glacier landforms are observed, on the western flanks of the great volcanoes and in the eastern Hellas region. This agreement points to an atmospheric origin for the ice and reveals how precipitation could have formed glaciers on Mars.

Phyllosilicates on Mars and implications for early martian climate

The recent identification of large deposits of sulphates by remote sensing and in situ observations has been considered evidence of the past presence of liquid water on Mars. Here we report the unambiguous detection of diverse phyllosilicates, a family of aqueous alteration products, on the basis of observations by the OMEGA imaging spectrometer on board the Mars Express spacecraft. These minerals are mainly associated with Noachian outcrops, which is consistent with an early active hydrological system, sustaining the long-term contact of igneous minerals with liquid water. We infer that the two main families of hydrated alteration products detected-phyllosilicates and sulphates--result from different formation processes. These occurred during two distinct climatic episodes: an early Noachian Mars, resulting in the formation of hydrated silicates, followed by a more acidic environment, in which sulphates formed.

Nightglow in the upper atmosphere of Mars and implications for atmospheric transport

We detected light emissions in the nightside martian atmosphere with the SPICAM (spectroscopy for the investigation of the characteristics of the atmosphere of Mars) ultraviolet (UV) spectrometer on board the Mars Express. The UV spectrum of this nightglow is composed of hydrogen Lyman alpha emission (121.6 nanometers) and the gamma and delta bands of nitric oxide (NO) (190 to 270 nanometers) produced when N and O atoms combine to produce the NO molecule. N and O atoms are produced by extreme UV photodissociation of O2, CO2, and N2 in the dayside upper atmosphere and transported to the night side. The NO emission is brightest in the winter south polar night because of continuous downward transport of air in this region at night during winter and because of freezing at ground level.

MEP (Mars Environment Package): toward a package for studying environmental conditions at the surface of Mars from future lander/rover missions

In view to prepare Mars human exploration, it is necessary to promote and lead, at the international level, a highly interdisciplinary program, involving specialists of geochemistry, geophysics, atmospheric science, space weather, and biology. The goal of this program will be to elaborate concepts of individual instruments, then of integrated instrumental packages, able to collect exhaustive data sets of environmental parameters from future landers and rovers of Mars, and to favour the conditions of their implementation. Such a program is one of the most urgent need for preparing human exploration, in order to develop mitigation strategies aimed at ensuring the safety of human explorers, and minimizing risk for surface operations. A few main areas of investigation may be listed: particle and radiation environment, chemical composition of atmosphere, meteorology, chemical composition of dust, surface and subsurface material, water in the subsurface, physical properties of the soil, search for an hypothesized microbial activity, characterization of radio-electric properties of the Martian ionosphere. Scientists at the origin of the present paper, already involved at a high degree of responsibility in several Mars missions, and actively preparing in situ instrumentation for future landed platforms (Netlander--now cancelled, MSL-09), express their readiness to participate in both ESA/AURORA and NASA programs of Mars human exploration. They think that the formation of a Mars Environment working group at ESA, in the course of the AURORA definition phase, could act positively in favour of the program, by increasing its scientific cross-section and making it still more focused on human exploration.

Formation of recent martian debris flows by melting of near-surface ground ice at high obliquity

The observation of small gullies associated with recent surface runoff on Mars has renewed the question of liquid water stability at the surface of Mars. The gullies could be formed by groundwater seepage from underground aquifers; however, observations of gullies originating from isolated peaks and dune crests question this scenario. We show that these landforms may result from the melting of water ice in the top few meters of the martian subsurface at high obliquity. Our conclusions are based on the analogy between the martian gullies and terrestrial debris flows observed in Greenland and numerical simulations that show that above-freezing temperatures can occur at high obliquities in the near surface of Mars, and that such temperatures are only predicted at latitudes and for slope orientations corresponding to where the gullies have been observed on Mars.

A weekly 24-h infusion of high-dose 5-fluorouracil (5-FU)+leucovorin and bi-weekly cisplatin (CDDP) was active and well tolerated in patients with non-colon digestive carcinomas

In patients with non-colon digestive carcinomas, various schedules and doses of 5-fluorouracil (5-FU) and leucovorin combined with cisplatin (CDDP) have been used extensively. The present study explored the toxicity and activity of a weekly 24-h infusion of high dose 5-FU modulated by high dose leucovorin with bi-weekly CDDP. 59 patients with measurable disease were treated with a weekly infusion of high dose 5-FU (2 or 2.6 g/m2)+leucovorin 500 mg/m2 for 6 weeks and a bi-weekly dose of CDDP (50 mg/m2). All patients had metastatic or locoregionally advanced disease and had a performance status < or =3. All patients were evaluable for toxicity and 58 for response. Toxicity was different according to the schedule of 5-FU. Serious adverse events occurred most frequently when 5-FU was given at a dose of 2.6 g/m2 with a high incidence of grade 3/4 neutropenia (16%) and febrile neutropenia (13%), and led to dose reductions in both CDDP and 5-FU in 13 patients (34%). For patients who started 5-FU at a dose of 2 g/m2, no reduction in 5-FU was required, and only 4 patients required a dose reduction of CDDP (19%). Grade 3/4 neutropenia was seen in 10% of patients of this group and only 1 patient required hospitalisation for febrile neutropenia. Other grade 3/4 toxicities were rare in both groups. Renal toxicity was infrequent and mild and did not require dose adjustments. The overall response rate was 33%; 19 patients achieved a partial responses (PR). No patient had a complete response (CR). The median duration of response was 5.7 months (range 2-24 months) and the median survival was 7.9 months ( range: 1-30, 95% confidence interval (CI): 7-9). The combination of weekly 24-h infusion of high dose 5-FU with leucovorin and bi-weekly cisplatin seems a well-tolerated and active treatment in non-colon digestive carcinomas. A dose of 2 g/m2 of 5-FU seems to be recommended.

Anticancer chemotherapy in a patient with prior history of acute intermittent porphyria. A case report and review of the literature

We describe the case of a patient with a prior history of acute intermittent porphyria (AIP) who needed the administration of anticancer drugs. Our experience with this patient and the limited experience reported in the literature show that it is probably safe to administer some chemotherapeutic agents, but it is important to prevent (or to minimize) the toxicities of these chemotherapeutic agents, as they seem to put the patient at major risk of an AIP crisis. Hematin and supportive treatments were useful treatments in our patient.

The state and future of Mars polar science and exploration

As the planet's principal cold traps, the martian polar regions have accumulated extensive mantles of ice and dust that cover individual areas of approximately 10(6) km2 and total as much as 3-4 km thick. From the scarcity of superposed craters on their surface, these layered deposits are thought to be comparatively young--preserving a record of the seasonal and climatic cycling of atmospheric CO2, H2O, and dust over the past approximately 10(5)-10(8) years. For this reason, the martian polar deposits may serve as a Rosetta Stone for understanding the geologic and climatic history of the planet--documenting variations in insolation (due to quasiperiodic oscillations in the planet's obliquity and orbital elements), volatile mass balance, atmospheric composition, dust storm activity, volcanic eruptions, large impacts, catastrophic floods, solar luminosity, supernovae, and perhaps even a record of microbial life. Beyond their scientific value, the polar regions may soon prove important for another reason--providing a valuable and accessible reservoir of water to support the long-term human exploration of Mars. In this paper we assess the current state of Mars polar research, identify the key questions that motivate the exploration of the polar regions, discuss the extent to which current missions will address these questions, and speculate about what additional capabilities and investigations may be required to address the issues that remain outstanding.

Warming early Mars with carbon dioxide clouds that scatter infrared radiation

Geomorphic evidence that Mars was warm enough to support flowing water about 3.8 billion years ago presents a continuing enigma that cannot be explained by conventional greenhouse warming mechanisms. Model calculations show that the surface of early Mars could have been warmed through a scattering variant of the greenhouse effect, resulting from the ability of the carbon dioxide ice clouds to reflect the outgoing thermal radiation back to the surface. This process could also explain how Earth avoided an early irreversible glaciation and could extend the size of the habitable zone on extrasolar planets around stars.

Absorption and scattering properties of the Martian dust in the solar wavelengths

A new wavelength-dependent model of the single-scattering properties of the Martian dust is presented. The model encompasses the solar wavelengths (0.3 to 4.3 micrometers at 0.02 micrometer resolution) and does not assume a particular mineralogical composition of the particles. We use the particle size distribution, shape, and single-scattering properties at Viking Lander wavelengths presented by Pollack et al. [1995]. We expand the wavelength range of the aerosol model by assuming that the atmospheric dust complex index of refraction is the same as that of dust particles in the bright surface geologic units. The new wavelength-dependent model is compared to observations taken by the Viking Orbiter Infrared Thermal Mapper solar channel instrument during two dust storms. The model accurately matches afternoon observations and some morning observations. Some of the early morning observations are much brighter than the model results. The increased reflectance can be ascribed to the formation of a water ice shell around the dust particles, thus creating the water ice clouds which Colburn et al. [1989], among others, have predicted.