Study of the Quality of Cosmonauts’ Activities When Simulating the EVA Environment on the Martian Surface in the Experiments Involving the ISS Crews.

The paper studies the possibilities and quality of performing a number of standard EVA operations by cosmonauts after a long-duration space mission aboard the ISS Russian Segment. Experiments have been conducted using the gravity offload stand that allows simulating the Martian gravity and conditions of spacesuited activity of cosmonauts on the planet surface. A comparative evaluation of the EVA operations performed by cosmonauts in pre- and post-flight experiments has been carried out.

ExoPhot: a new approach for the study of photosynthesis viability in exoplanetary systems.

<p>NASA and ESA are making plans for the next generation of space telescopes, which should be able to detect biomarkers in the atmospheres of exoplanets in the classical habitable zones around their stars (i.e., the range of separations at which water would be in liquid state on the exoplanet surface). The launch of <em>James Space Webb Telescope</em> is scheduled for October 2021. The main questions are related with the type of organisms producing such possible biomarkers and with the related metabolism? Will autotrophs be the base of the exoplanet ecological pyramid, as on Earth? Will they be phototroph or chemotroph? Will they be photosynthetic? Oxygenic or anoxygenic? Which will their photosynthetic pigments be? ESA’s <em>LIFE</em> or any other new concept for which scientific requirements have not been defined yet might be able to not only detect biomarkers, but to shed light on the actual biochemistry of exoplanet ecosystems. Therefore, investigating the potential variety of photosynthetic systems in exoplanets, either real or to be discovered, is actually very timely, as the requirements of new such telescope concepts are not set yet.</p> <p>The conversion of solar energy to chemical energy through photosynthesis is considered one of the first metabolic routes on planet Earth. Although a low percentage of the solar radiation from our Sun is captured by photosynthesis, this metabolic route provides the energy to drive all the life on Earth. Cyanobacteria are thought to be the first photosynthetic microorganisms on Earth. Subsequent photosynthetic organisms acquired photosynthesis via cyanobacteria endosymbionts, that evolved into chloroplasts in plants (Tomioka & Sugiura 1983).</p> <p>At the same time, photosynthesis modified the atmosphere of the early Earth by producing oxygen as a by-product. The concentration in this gas was increased in the primitive atmosphere, transforming the metabolic possibilities for the rest of organisms and, nowadays, oxygen supports the whole aerobic organisms on the planet. The only requirements that photosynthesis has are the exposure to optical radiation from the corresponding star and the availability of water and carbon dioxide (as a carbon source), making photosynthesis a putative imperative metabolism to be present in any particular radiative planetary system.</p> <p>To deepen into this idea, ExoPhot aims to study the relation between photosynthetic systems on exoplanets around different types of stars (i.e. stellar spectral types) from an astrobiological and multidisciplinary point of view, by focusing on two aspects:</p> <ul> <li>Assess the photosynthetic fitness of a variety of photopigments (either real or hypothetical) as a function of star, exoplanet and atmospheric scenario.</li> <li>Delineate a range of stellar, exoplanet and atmospheric parameters for which photosynthetic activity might be feasible.</li> </ul> <p>To accomplish these goals, we will use state-of-the-art planetary and stellar models to retrieve the radiation signatures at the planet surface for a wide range of exoplanet, atmosphere and host star parameters, and will carry out a quantification of the overlap (convolution) between those spectra with the absorption spectra of photosynthetic pigments, both terrestrial and hypothetical (our own developments on computer-simulated primordial pigments). Here, at the EPSC2021 conference, we present our preliminary results and future work to be developed.</p> <p> </p> <p><em>Bibliography:</em></p> <p>Tomioka, N. & Sugiura, M. The complete nucleotide sequence of a 16S ribosomal RNA gene from a blue-green alga, Anacystis nidulans. <em>Molecular and General Genetics, </em>1983<em>, 191</em>, 46–50. https://doi.org/10.1007/BF00330888</p> <p> </p>

INVOLVEMENT OF ALTIMETRY INFORMATION INTO THE IMPROVED PHOTOCLINOMETRY METHOD FOR RELIEF RETRIEVAL FROM A SLOPE FIELD

Purpose: The paper discusses the possibility for increasing the planet’s surface relief retrieving accuracy with the improved photoclinometry method through the reference of the desired relief to the altimetry data. The general approach to solving the problem is proposed. The use of altimeters having both wide and narrow beam patterns are discussed, but the narrow beam pattern altimeter data is studied more in detail. The spatial resolution of the retrieved relief calculated with the improved photoclinometry method conforms to the one of the source images. Altimetry allows absolute reference to the surface heights and improves the accuracy of the relief determination. Design/metodology/approach: The work is based on the improved photoclinometry method for the planet’s surface relief retrieving from images. This method is mathematically rigorous and uses the Bayesian statistical approach, that allows calculation of the most probable relief according to available observations. Findings: An approach to determining the optimal statistical estimate of the surface heights from images in the frames of the improved photoclinometry method is proposed and an expression for the optimal filter which converts source images along with the wide beam pattern altimetry data into the most probable relief of the planet surface area is presented. The reference technique for the narrow beam pattern altimeter data is formulated. The efficiency of the method has been verified with the computer simulation. The relief of the surface area in Mare Imbrium on the Moon was retrieved using three images and laser altimeter data taken by the “Lunar Reconnaissance Orbiter” spacecraft. Conclusions: Accounting for the narrow beam pattern altimeter data increases the accuracy of the relief determination. Using the narrow beam pattern altimeter data turns out to be more preferable over the involving wide beam pattern altimeter data. Computer simulation has shown that accounting for the narrow beam pattern altimeter data significantly increases the accuracy of the calculated heights as against using images exclusively and helps to speed up the calculation procedure. Key words: planet surface relief; photometry; altimetry; optimal filtering; statistical estimation of random value

Marine natural products: the new generation of pharmacotherapeutics

The biomedical potential of the sea has gone largely unexplored so far, despite the fact that it covers three quarters of the planet surface and the fact that life on Earth originated from the sea. However, with the arrival of the professional deep sea divers, the marine researchers have gained access to all sorts of marine creatures like sponges, corals, sea urchins, sea squirts, hydroids, sea anemones, fishes and mollusks as well as to varied types of sea plants including algae and the other micro-organisms embedded in the sea bed. The biomedical scientists are exploiting these all to extract marine natural products (MNPs) having pharmacological properties that may one day cure long list of illnesses varying from bacterial infections to cancer, Alzheimer's and AIDS and was the focus of this review article.

Trajectory Design of Perseus: A CubeSat Mission Concept to Phobos

The Martian satellites Phobos and Deimos hold many unanswered questions that may provide clues to the origin of Mars. These moons are low Δv stopover sites to Mars. Some human missions to Mars typically identify Phobos and Deimos as staging bases for Mars surface exploration. Astronauts could base initial operations there in lieu of repeated voyages to and from the planet surface, to refuel transiting spacecraft, to teleoperate robotics and other critical machinery, and to develop habitable infrastructure ahead of human landings. Despite their strategic and scientific significance, there has been no successful dedicated mission to either moon. For this reason, we propose Perseus, a geological imaging CubeSat mission to Phobos. Perseus, a 27U, 54kg CubeSat will return thermal and visible images at resolutions better than currently available over most of Phobos’ surface. This includes visible images at 5m/pixel and thermal images at 25m/pixel of Phobos’ surface. The Perseus mission is nominally intended to be a co-orbital mission, where the spacecraft will encounter Phobos on its Martian orbit. However, a hyperbolic rendezvous mission concept, to image Phobos on a hyperbolic flyby, is also considered to reduce the risks associated with orbit capture and to reduce mission costs. This paper presents the preliminary feasibility, science objectives, and technological development challenges of achieving these science goals. We then formulate two rendezvous concepts as a series of three nonlinear optimization problems that span the design tree of mission concepts. The tree’s root node is the heliocentric cruise problem, which identifies the near-optimal launch and arrival windows for the Perseus spacecraft. The leaf nodes of the design tree are the two rendezvous concepts that identify near-optimal co-orbital and hyperbolic trajectories for Phobos’ reconnaissance. The design problems are solved using evolutionary algorithms, and the performance of the selected mission concepts is then examined. The results indicate that a co-orbital encounter allows about one encounter per day with about 6 min per encounter. The hyperbolic encounter, on the other hand, allows a single encounter where the spacecraft will spend about 2 min in the imaging region with respect to Phobos. The spacecraft will obtain higher resolution images of Phobos on this feasible region than have ever been seen for most of the surface. These detailed images will help identify candidate landing sites and provide critical data to derisk future surface missions to Phobos.

Gamma-ray bursts: not so much deadlier than we thought

ABSTRACT We analyse the additional effect on planetary atmospheres of recently detected gamma-ray burst afterglow photons in the range up to 1 TeV. For an Earth-like atmosphere, we find that there is a small additional depletion in ozone versus that modeled for only prompt emission. We also find a small enhancement of muon flux at the planet surface. Overall, we conclude that the additional afterglow emission, even with TeV photons, does not result in a significantly larger impact over that found in past studies.

Climate bistability of rocky exoplanets

<p>Until about 600 million years ago, our planet experienced temporary snowball conditions, with continental and sea ices covering a large fraction of its surface. This points to a potential bistability of Earth’s climate, that can have at least two different (statistical) equilibrium states for the same external forcing (i.e., solar radiation). Here we explore the probability of finding bistable climates in rocky exoplanets, and consider the properties of planetary climates obtained by varying the semi-major orbital axis (thus, received stellar radiation), eccentricity and obliquity, and atmospheric pressure. To this goal, we use the Earth-like planet surface temperature model (ESTM), an extension of 1D Energy Balance Models developed to provide a numerically efficient climate estimator for parameter sensitivity studies and long climatic simulations. After verifying that the ESTM is able to reproduce Earth climate bistability, we identify the range of parameter space where climate bistability is detected. An intriguing result of the present work is that the planetary conditions that support climate bistability are remarkably similar to those required for the sustainance of complex, multicellular life on the planetary surface. The exploration of potential climate bistability proceeds with the case of a Earth-like planet partially covered by vegetation that generates a positive vegetation-albedo feedback, in the spirit of the Charney conceptual model. In this case, it is shown that the presence of this vegetation feedback can induce relevant changes in climate dynamics and alter the range of habitable conditions for the planet.</p>

The development of Anthropocene biotas

Biodiversity has always responded dynamically to environmental perturbations in the geological past, through changes to the abundances and distributions of genes and species, to the composition of biological communities, and to the cover and locations of different ecosystem types. This is how the ‘nature’ that exists today has survived. The same is true in the Anthropocene. The entire planet surface has been altered by humans, ranging from direct vegetation transformation and removal of most of the world's megafauna, through to atmospheric changes in greenhouse gasses and consequent climatic changes and ocean acidification. These anthropogenic perturbations have led to the establishment of genes and species in new locations, thus generating novel communities and ecosystems. In this historical context, recent biological changes should be seen as responses to multiple drivers of change, rather than being a problem per se . These changes are the means by which the biosphere is adjusting to and will ultimately survive the Anthropocene. Thus, management and conservation of the biological world, and our place in it, requires a transition from trying to minimize biological change to one in which we facilitate dynamism that accelerates the rates at which species and ecosystems adjust to human-associated drivers of change. This article is part of the theme issue ‘Climate change and ecosystems: threats, opportunities and solutions’.

Application of nanosatellites PlanetScope data to monitor crop growth

In this research, an approach to monitor crop growth and development is presented using time series satellite data of high spatial resolution. Monitoring of winter wheat phenology based on images of PlanetScope constellations is considered. By applying various PlanetScope data processing types and ground based GreenSeeker data, differences of NDVI values at two variants of crop fertilization are determined. In particular, the following approaches were used in the research: obtaining the Top of Atmosphere Reflectance (TOA), the Planet Surface Reflectance (SR), and receiving NDVI image in Python using a Rasterio module. It was estimated that NDVI values derived from the surface reflectance imagery were significantly correlated to the ground data of a manual active GreenSeeker optical sensor (p < 0.05). The proposed simplified technique, based on PlanetScope NDVI time series, demonstrates the possibilities to monitor temporal changes in crop growth.

Climate bistability of Earth-like exoplanets

ABSTRACT Before about 500 million years ago, most probably our planet experienced temporary snowball conditions, with continental and sea ices covering a large fraction of its surface. This points to a potential bistability of Earth’s climate that can have at least two different (statistical) equilibrium states for the same external forcing (i.e. solar radiation). Here, we explore the probability of finding bistable climates in Earth-like exoplanets and consider the properties of planetary climates obtained by varying the semimajor orbital axis (thus, received stellar radiation), eccentricity and obliquity, and atmospheric pressure. To this goal, we use the Earth-like planet surface temperature model (ESTM), an extension of one-dimensional Energy Balance Models developed to provide a numerically efficient climate estimator for parameter sensitivity studies and long climatic simulations. After verifying that the ESTM is able to reproduce Earth climate bistability, we identify the range of parameter space where climate bistability is detected. An intriguing result of this work is that the planetary conditions that support climate bistability are remarkably similar to those required for the sustenance of complex, multicellular life on the planetary surface. The interpretation of this result deserves further investigation, given its relevance for the potential distribution of life in exoplanetary systems.