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In der Strahlentherapie ist es fundamental den Strahlenschaden im Hinblick auf die Tumorkontrolle und auf Normalgewebskomplikationen zu steuern. Somit müssen Therapieansätze einen Kompromiss zwischen der applizierbaren Dosis für den klonogenen Zelltod der Tumorzellen und möglichen Nebenwirkungen finden. Mithilfe von strahlenbiologischen Experimenten können weitere Erkenntnisse über die schädigende Strahlenwirkung gewonnen werden. Diese Arbeit stellt drei unterschiedliche und unabhängige Forschungsansätze in der Physik der Protonentherapie von der Größenordnung Millimeter bis zu Nanometer vor, um strahlenbiologische Experimente und damit den langfristigen Therapieerfolg zu verbessern. Im ersten Projekt wird eine Methode zur Optimierung der Feldformung bei der Behandlungsmodalität von gescannten Protonennadelstrahlen in Kombination mit kollimierenden Aperturen präsentiert. Eine optimierte Positionierung des Spots relativ zur Aperturkante erzeugt dabei eine kleinere laterale Penumbra. In einem zweiten Projekt wird ein Versuchsaufbau entwickelt und optimiert, um Protonen, die ursprünglich auf klinische Energien beschleunigt wurden, so effizient wie möglich mit einer beliebigen Energie bis hinunter zu wenigen MeV bereitzustellen. Mit einem optimalen Setup können niederenergetische Protonen mit maximaler Effizienz für strahlenbiologische Experimente bereitgestellt werden. Das dritte Projekt untersucht den strahlensensitiven Effekt von Platinnanopartikeln (PtNPs) in der Protonentherapie, der potentiell eine erhöhte Tumorkontrolle bei der Behandlung bewirken kann. Es wird experimentell nachgewiesen, dass der strahlensensitive Effekt von PtNPs in der Protonentherapie nicht in einer erhöhten Energiedeposition der Protonen auf makroskopischer Skala begründet liegt. Insgesamt liefern die in dieser Arbeit untersuchten Projekte individuelle Beiträge zur Physik in der strahlenbiologischen Forschung und damit zur Verbesserung der Strahlenwirkung in der Protonentherapie., In radiotherapy, it is fundamental to manage the radiation damage in terms of tumor control and normal tissue complications. Thus, therapeutic strategies aim to find a compromise between the applicable dose for clonogenic cell death of the tumor cells and possible side effects. Radiobiological experiments may provide further insight into the damaging effects of radiation. Here, three different and independent research approaches in proton therapy physics from the millimeter to nanometer scale are introduced to improve radiobiological experiments and thus long-term therapeutic outcome. The first project presents a method to optimize field shaping in the treatment modality of proton pencil beam scanning in combination with collimating apertures. An optimized positioning of the spot relative to the aperture edge results in a smaller lateral penumbra. In a second project, an experimental setup is developed and optimized to deliver protons originally accelerated to clinical energies as efficiently as possible with an arbitrary energy down to only a few MeV. With an optimal absorber thickness, low-energetic protons can be provided with maximum efficiency for radiobiology experiments. The third project investigates the radiosensitizing effect of platinum nanoparticles (PtNPs) in proton therapy, which can potentially induce increased tumor control during treatment. It is experimentally demonstrated that the radiosensitizing effect of PtNPs in proton therapy is not due to an increased proton energy deposition at the macroscopic scale. Overall, the projects investigated in this work provide individual contributions to physics in the radiobiological research and thus to the improvement of the radiation effect in proton beam therapy.

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAM, Background: Extreme terrestrial, analogue environments are widely used models to study the limits of life and to infer habitability of extraterrestrial settings. In contrast to Earth’s ecosystems, potential extraterrestrial biotopes are usually characterized by a lack of oxygen. Methods: In the MASE project (Mars Analogues for Space Exploration), we selected representative anoxic analogue environments (permafrost, salt-mine, acidic lake and river, sulfur springs) for the comprehensive analysis of their microbial communities. We assessed the microbiome profile of intact cells by propidium monoazide-based amplicon and shotgun metagenome sequencing, supplemented with an extensive cultivation effort. Results: The information retrieved from microbiome analyses on the intact microbial community thriving in the MASE sites, together with the isolation of 31 model microorganisms and successful binning of 15 high-quality genomes allowed us to observe principle pathways, which pinpoint specific microbial functions in the MASE sites compared to moderate environments. The microorganisms were characterized by an impressive machinery to withstand physical and chemical pressures. All levels of our analyses revealed the strong and omnipresent dependency of the microbial communities on complex organic matter. Moreover, we identified an extremotolerant cosmopolitan group of 34 poly-extremophiles thriving in all sites. Conclusions: Our results reveal the presence of a core microbiome and microbial taxonomic similarities between saline and acidic anoxic environments. Our work further emphasizes the importance of the environmental, terrestrial parameters for the functionality of a microbial community, but also reveals a high proportion of living microorganisms in extreme environments with a high adaptation potential within habitability borders. Keywords: Extreme environments, Microbiomes, Archaea, Bacteria, Propidium monoazide, Astrobiology, Spaceanalogue, Extremophiles, Extraterrestrial life, Metagenomics

Radiation of ionizing or non-ionizing nature has harmful effects on cellular components like DNA as radiation can compromise its proper integrity. To cope with damages caused by external stimuli including radiation, within living cells, several fast and efficient repair mechanisms have evolved. Previous studies addressing organismic radiation tolerance have shown that radiotolerance is a predominant property among extremophilic microorganisms including (hyper-) thermophilic archaea. The analysis of the ionizing radiation tolerance of the chemolithoautotrophic, obligate anaerobic, hyperthermophilic Crenarchaeon Ignicoccus hospitalis showed a D10-value of 4.7 kGy, fourfold exceeding the doses previously determined for other extremophilic archaea. The genome integrity of I. hospitalis after γ-ray exposure in relation to its survival was visualized by RAPD and qPCR. Furthermore, the discrimination between reproduction, and ongoing metabolic activity was possible for the first time indicating that a potential viable but non-culturable (VBNC) state may also account for I. hospitalis.

BackgroundThe extraordinarily resistant bacteriumDeinococcus radioduranswithstands harsh environmental conditions present in outer space.Deinococcus radioduranswas exposed for 1 year outside the International Space Station within Tanpopo orbital mission to investigate microbial survival and space travel. In addition, a ground-based simulation experiment with conditions, mirroring those from low Earth orbit, was performed.MethodsWe monitoredDeinococcus radioduranscells during early stage of recovery after low Earth orbit exposure using electron microscopy tools. Furthermore, proteomic, transcriptomic and metabolomic analyses were performed to identify molecular mechanisms responsible for the survival ofDeinococcus radioduransin low Earth orbit.ResultsD. radioduranscells exposed to low Earth orbit conditions do not exhibit any morphological damage. However, an accumulation of numerous outer-membrane-associated vesicles was observed. On levels of proteins and transcripts, a multi-faceted response was detected to alleviate cell stress. The UvrABC endonuclease excision repair mechanism was triggered to cope with DNA damage. Defense against reactive oxygen species is mirrored by the increased abundance of catalases and is accompanied by the increased abundance of putrescine, which works as reactive oxygen species scavenging molecule. In addition, several proteins and mRNAs, responsible for regulatory and transporting functions showed increased abundances. The decrease in primary metabolites indicates alternations in the energy status, which is needed to repair damaged molecules.ConclusionLow Earth orbit induced molecular rearrangements trigger multiple components of metabolic stress response and regulatory networks in exposed microbial cells. Presented results show that the non-sporulating bacteriumDeinococcus radioduranssurvived long-term low Earth orbit exposure if wavelength below 200 nm are not present, which mirrors the UV spectrum of Mars, where CO2effectively provides a shield below 190 nm. These results should be considered in the context of planetary protection concerns and the development of new sterilization techniques for future space missions.

A radiative transfer model for the determination of UV radiation on arbitrarily oriented surfaces is validated by spectral measurements taken directly on the inner surface of a cockpit window of an Airbus A321-231 during a flight from Frankfurt, Germany to Málaga, Spain on 23 August, 2018. The simulations consider the UV spectral range from 290 nm to 400 nm and take into account both the measured spectral transmittance of a cockpit window as well as its construction-related orientation. Comparisons are performed for selected route segments with largely cloud-free conditions. The cruising level of the Airbus on these segments was nearly constant between 11.27 km and 11.29 km. UV irradiance measurements at the cockpit window give values within a range of 19 W/m2 and 26 W/m2. The comparison of modelled and measured irradiances show a very good agreement, i.e. the relative differences between simulated and measured values range from -2.1 % to +4.3 %. In addition, horizontally and vertically oriented sensors are simulated for the same flight. The validation results generally underpin the application potential of the model. As an example of this, UV irradiances incident on differently oriented surfaces, as could occur inside and outside of a future flying taxi on a short-haul flight between Munich and Augsburg at low cruising level, are shown.

Radioligand therapy (RLT) targeting prostate-specific membrane antigen (PSMA) is a promising systemic treatment for metastatic castration-resistant prostate cancer (mCRPC) when conventional treatments are no longer an option. Although PSMA-targeted RLT is a viable treatment option for mCRPC, the effect of therapy varies from patient to patient. The therapeutic effect is generally determined by the absorbed dose and absorbed dose rate in tumors and normal organs, which depend on the choice of radionuclide, ligand properties, and individual patients' biokinetics. Measurement before therapy, e.g., PET/CT, is becoming increasingly essential to accurately estimate the absorbed dose in therapy. Varying ligand amounts, ligand properties, and radionuclides can affect the efficacy of PSMA-targeted imaging and therapy. Inter-patient variability, such as total tumor volume (TTV), must also be considered as it affects the biodistribution of radioligand in the patient. A more detailed understanding of the important parameters affecting imaging and therapy of PSMA-targeted RLT is needed. Therefore, this thesis aimed to investigate 1) the effect of TTV on the biologically effective dose (BED) to tumors and organs at risk (OAR), 2) the effects of ligand amounts, affinities, and internalization on imaging and therapy, and 3) the effects of radionuclide half-lives, ligand affinities, and measurement time points after injection on tumor and background activity. For this purpose, 13 patients with mCRPC treated with 177-Lu-PSMA I&T were included. A physiologically-based whole-body pharmacokinetic (PBPK) model for PSMA-specific ligands was developed based on PSMA-11 and PSMA I&T and implemented in MATLAB® software packages (Simulink and Simbiology). The PBPK model was fitted to biokinetics data of 13 patients to estimate individual patient parameters. The PBPK model with individually estimated parameters (virtual patients) was utilized for the simulations with MATLAB®. The effect of TTV on absorbed dose and BED was investigated by simulating TTVs of 0.1-10 L for tumors and OAR. The activity and amount of ligand to be administered leading to an optimal tumor to kidney ratio were also investigated. The effects of ligand properties on PET/CT imaging and therapy were studied for ligand amounts (1-1000 nmol), association rates kon (0.1-0.01 L/nmol/min), dissociation rates koff (0.1-0.0001 min-1), and internalization rates λint (0.01-0.0001 min-1). The activity was normalized to volume and administered activity for imaging (68Ga-PSMA at 1 h). The absorbed dose of 7.3 GBq 177-Lu-PSMA was calculated for therapy. Three radionuclides with different half-lives 68Ga (t1/2 = 1.13 h), 18F (t1/2 = 1.83 h), and 64Cu (t1/2 = 12.7 h) were simulated for different affinities (dissociation constants KD of 1-0.01 nM). A common ligand amount of 3 nmol investigated the effects of radionuclide half-life and ligand affinity on activity concentration in PET/CT imaging. Activity concentrations were calculated at various time points (1, 2, 3, 4, 8, 12, and 16 h p.i.). Simulated BEDs decreased in tumor lesion (58% ± 18%), kidneys (58% ± 17%), parotid glands (59% ± 16%), and submandibular glands (59% ± 16%) when TTV was increased from 0.3 to 3 L. BED for red bone marrow increased (185% ± 29%). The optimal ligand amount and activity were 273 ± 136 nmol and 10.4 ± 4.4 GBq, respectively, in patients with a TTV greater than 0.3 L. The effects of ligand properties on therapy were greater than those of imaging. The combination of ligand properties (kon = 0.1 L/nmol/min, and koff = 0.01 min-1) resulted in the highest tumor uptake for imaging using commonly used ligand amounts (1-10 nmol). The higher the internalization rate, the higher ligand amount is required for an appropriate tumor-to-kidney ratio in therapy. Choosing the optimal amount of ligand became more crucial as the affinity increased. The maximum tumor uptake was achieved 1 h p. i. for 68-Ga-PSMA in a simulated study on the effect of the radioactive half-life on PET/CT imaging for varied ligand affinities. The maximum tumor uptake was at 1 h p. i. and 2 h p. i. for 18-F-PSMA, for dissociation constants KD = 1 nM and KD = 0.1-0.01 nM, respectively. The maximum tumor uptake for 64-Cu-PSMA was observed at 4 h p.i. for dissociation constant KD = 1 nM, and at 4 h p. i. (9 patients) and 8 h p. i. (4 patients) for higher affinities. Activity concentrations in the tumor increased 1.3-fold for 18F-PSMA (2 h p.i.) compared to 68-Ga-PSMA (1 h p.i.), with insignificant differences for all affinities. The improvements in 64-Cu-PSMA (4 h p. i.) were 2.8 to 3.2-fold for all affinities. The presented results provide essential information to optimize imaging and therapy of PSMA-targeted RLT. It can be concluded that: 1. The total tumor volume strongly influences the absorbed dose and BED in tumors and OAR. Patients with a high tumor burden can receive more activities and ligands without exceeding the tolerable BED for the OAR to improve the therapeutic effect. 2. The higher the ligand affinity, the more important the optimal amount of ligand was chosen. 3. The highest tumor-to-background ratio can be achieved after 4 h in PET/CT with the commonly used ligand amounts of the high-affinity 64-Cu-PSMA target ligands.

The ICCHIBAN project was an international collaboration to intercalibrate and intercompare the response of the different detectors and instruments used for radiation dosimetry aboard manned spacecraft. The objectives of the ICCHIBAN project were: 1) to determine the response of space radiation instruments and dosimeters to heavy ions of charge and energy similar to that found in the galactic cosmic radiation (GCR) spectrum; 2) to compare the response and sensitivity of various space radiation monitoring instruments and aid in reconciling differences in measurements made by various radiation instruments during space flight; and 3) to establish and characterize a heavy ion “reference standard” against which space radiation instruments can be calibrated. ICCHIBAN experiments were carried out at a number of particle accelerator facilities, the vast majority, eight, using the HIMAC heavy ion accelerator at the National Institute for Radiological Sciences, Chiba, Japan. Benefits of the ICCHIBAN project included the identification and correction of problems in calibration and data interpretation of a number of active space radiation instruments, and the demonstration of the overall efficacy and reproducibility of passive radiation dosimeters, especially luminescence-based detectors such as TLD and OSLD used in conjunction with CR-39 PNTD.

Solar energetic particles are one of the main sources of particle radiation seen in space. In the first part of September 2017 the most active solar period of cycle 24 produced four large X-class flares and a series of (interplanetary) coronal mass ejections, which gave rise to radiation storms seen over all energies and at the ground by neutron monitors. This paper presents comprehensive cross comparisons of in situ radiation detector data from near-Earth satellites to give an appraisal on the state of present data processing for monitors of such particles. Many of these data sets have been the target of previous cross calibrations, and this event with a hard spectrum provides the opportunity to validate these results. As a result of the excellent agreement found between these data sets and the use of neutron monitor data, this paper also presents an analytical expression for fluence spectrum for the event. Derived ionizing dose values have been computed to show that although there is a significant high-energy component, the event was not particularly concerning as regards dose effects in spacecraft electronics. Several sets of spacecraft data illustrating single event effects are presented showing a more significant impact in this regard. Such a hard event can penetrate thick shielding; human dose quantities measured inside the International Space Station and derived through modeling for aircraft altitudes are also presented. Lastly, simulation results of coronal mass ejection propagation through the heliosphere are presented along with data from Mars-orbiting spacecraft in addition to data from the Mars surface.

Planetary Protection is an international concern and responsibility. The international standard for planetary protection has been developed by the Committee on Space Research (COSPAR) which provides a forum for international consultation and has formulated a Planetary Protection Policy with associated requirements that are put in place after examination of the most updated relevant scientific studies and recommendations made by the COSPAR Panel on Planetary Protection. The COSPAR Planetary Protection Policy, and its associated requirements, is not legally binding under international law but it is the only internationally agreed planetary protection standard with implementation guidelines for reference in compliance with Article IX of the United Nations Outer Space Treaty of 1967. States Parties to the Outer Space Treaty are responsible for national space activities under Article VI, including the activities of governmental and non-governmental entities. It is the State that ultimately will be held responsible for wrongful acts committed by its jurisdictional subjects.

There is a need to investigate new countermeasures against the detrimental effects of ionizing radiation as deep space exploration missions are on the horizon.Objective: In this systematic review, the effects of physical exercise upon ionizing radiation-induced damage were evaluated.Methods: Systematic searches were performed in Medline, Embase, Cochrane library, and the databases from space agencies. Of 2,798 publications that were screened, 22 studies contained relevant data that were further extracted and analyzed. Risk of bias of included studies was assessed. Due to the high level of heterogeneity, meta-analysis was not performed. Five outcome groups were assessed by calculating Hedges' g effect sizes and visualized using effect size plots.Results: Exercise decreased radiation-induced DNA damage, oxidative stress, and inflammation, while increasing antioxidant activity. Although the results were highly heterogeneous, there was evidence for a beneficial effect of exercise in cellular, clinical, and functional outcomes.Conclusions: Out of 72 outcomes, 68 showed a beneficial effect of physical training when exposed to ionizing radiation. As the first study to investigate a potential protective mechanism of physical exercise against radiation effects in a systematic review, the current findings may help inform medical capabilities of human spaceflight and may also be relevant for terrestrial clinical care such as radiation oncology.

Introduction: Long-term space missions are accompanied by harmful environmental conditions like microgravity. Due to the reduced gravity, astronauts adapt to their environment resulting in tissue fluidic shifts. Since the knowledge about microbiome data in space is sparse and conduction of experiments at the ISS is complex, suitable analogs are needed. Therefore, the first cooperative bed-rest study called Artificial Gravity Bed-Rest study with ESA (AGBRESA), by NASA, ESA and DLR offered optimal features to investigate possible correlations between microbial shifts and physiological microgravity by using -6° head-downtilt (HDT). The aim of this survey was to identify changes within the standardized conditions, such as diet and wrongly distributed tissue fluids to reveal causal connections among health state and microbial communities.

The EDEN ISS greenhouse, integrated in two joined containers, is a confined mobile test facility in Antarctica for the development and optimization of new plant cultivation techniques for future space programs. The EDEN ISS greenhouse was used successfully from February to November 2018 for fresh food production for the overwintering crew at the Antarctic Neumayer III station. During the 9 months of operation, samples from the different plants, from the nutrition solution of the aeroponic planting system, and from diverse surfaces within the three different compartments of the container were taken [future exploration greenhouse (FEG), service section (SS), and cold porch (CP)]. Quantity as well as diversity of microorganisms was examined by cultivation. In case of the plant samples, microbial quantities were in a range from 102 to 104 colony forming units (CFU) per gram plant material. Compared to plants purchased from a German grocery, the produce hosted orders of magnitude more microorganisms than the EDEN ISS plants. The EDEN ISS plant samples contained mainly fungi and a few bacteria. No classical food associated pathogenic microorganism, like Escherichia and Salmonella, could be found. Probably due to the used cultivation approach, Archaea were not found in the samples. The bioburden in the nutrition solutions increased constantly over time but never reached critical values like 10² –10³ CFU per 100 mL in irrigation water as it is stated, e.g., for commercial European plant productions. The surface samples revealed high differences in the microbial burden between the greenhouse part of the container and the SS and CP part. However, the numbers of organisms (bacteria and fungi) found in the planted greenhouse were still not critical. The microbial loaded surfaces showed strong temporal as well as spatial fluctuations. In samples of the nutrition solution and the surface, the number of bacteria exceeded the amount of fungi by many times. For identification, 16S rRNA gene sequencing was performed for the isolated prokaryotic organisms. Phylogenetic analyses revealed that the most abundant bacterial phyla were Firmicutes and Actinobacteria. These phyla include plant- and human-associated bacterial species. In general, it could be shown that it is possible to produce edible fresh food in a remote environment and this food is safe for consumption from a microbiological point of view.

Long term human space missions require efficient strategies to sustain crew health and safety. This is why we need to develop improved spaceflight-suitable methods for microbiological monitoring and contamination control. Especially microbial biofilms are of concern in spaceflight because they can damage equipment by polymer deterioration, corrode metal and cause bio-fouling. Furthermore, biofilms can harbor pathogenic microorganisms that can cause infections which is unwanted, especially since it is known that the immune system of astronauts is impaired during spaceflight. Antimicrobial surfaces reduce the ability of microorganisms to form biofilms and can therefore be helpful in sustaining spaceship integrity as well as the astronaut’s health. Metals such as silver, copper and their alloy are known to have antimicrobial properties. The introduction of antimicrobial surfaces for medical, pharmaceutical and industrial purposes has already shown a unique potential for reducing and preventing microbial contamination. However, their efficiency within the spaceflight context still has to be investigated in further detail: The European Space Agency (ESA) selected project BIOFILMS (No. ILSRA-2014-054) will test the effect of tailor-made nanostructured copper-based surfaces on bacterial biofilm in an experiment aboard the International Space Station (ISS). BIOFILMS is an acronym that stands for “Biofilm Inhibition on Flight equipment and on board the ISS using microbiologically Lethal Metal Surfaces". In the project, three spaceflight relevant bacterial species will be tested: Acinetobacter radioresistens, Cupriavidus metallidurans and Staphylococcus capitis. Steel is going to be used as a refence surface for biofilm formation and the antimicrobial surfaces are copper-based. They differ in their antimicrobial activity based on chemical composition and/or geometric nanostructures. The innovative approach is that the surfaces are patterned in a process called Direct Laser Interference Patterning (DLIP) using ultra-short pulses (USP). The surfaces will be evaluated for biofilm formation rates under different spaceflight relevant gravitational regimes (Mars, ISS and Earth control) and bacterial growth will occur under optimal biofilm-inducing conditions in the KUBIK incubator inside ESA’s Columbus laboratory. Preflight experiments, performed on ground (1g), showed that the BIOFILMS hardware is biocompatible and allows biofilm formation of all three bacterial species on the reference steel surfaces. The use of pure copper and brass surfaces inside the hardware significantly reduced bacterial growth and biofilm formation. In our preliminary experiments, the DLIP nanostructured copper surfaces were more effective than the smooth surfaces. The obtained results from the BIOFILMS experiment will be of immense importance for understanding the influence of gravity on biofilm formation and on the effectivity of USP-DLIP antimicrobial copper surfaces. Furthermore, the evaluation of different antimicrobial materials in microgravity is relevant for present and future astronaut-/robotic-associated activities in space exploration. Here, an overview on the ongoing and upcoming activities of the ISS spaceflight experiment BIOFILMS is presented.

As humans explore and settle in space, they will need to mine elements to support industries such as manufacturing and construction. In preparation for the establishment of permanent human settlements across the Solar System, we conducted the ESA BioRock experiment on board the International Space Station to investigate whether biological mining could be accomplished under extraterrestrial gravity conditions. We tested the hypothesis that the gravity (g) level influenced the efficacy with which biomining could be achieved from basalt, an abundant material on the Moon and Mars, by quantifying bioleaching by three different microorganisms under microgravity, simulated Mars and Earth gravitational conditions. One element of interest in mining is vanadium (V), which is added to steel to fabricate high strength, corrosion-resistant structural materials for buildings, transportation, tools and other applications. The results showed that Sphingomonas desiccabilis and Bacillus subtilis enhanced the leaching of vanadium under the three gravity conditions compared to sterile controls by 184.92 to 283.22%, respectively. Gravity did not have a significant effect on mean leaching, thus showing the potential for biomining on Solar System objects with diverse gravitational conditions. Our results demonstrate the potential to use microorganisms to conduct elemental mining and other bioindustrial processes in space locations with non-1 × g gravity. These same principles apply to extraterrestrial bioremediation and elemental recycling beyond Earth.

Ignicoccus hospitalis is an extremophilic Archaea that has demonstrated an extraordinary high tolerance to ionizing radiation. The cells remain viable after exposure to X-ray doses up to 12 kGy, metabolically active after up to 118 kGy and completely repair DNA damages within one hour. This is surprising since ionizing radiation is not present in its natural habitat - a submarine system of hydrothermal vents. In this work, the origin and mechanisms of I. hospitalis radiation tolerance are being addressed studying the intracellular-specific protection (e.g. polyploidy, compatible solutes, histone-like proteins and Mn²⁺/Fe² ratio). Therefore, different growth parameters have been tested and DNA extraction protocols optimized to gain information about numbers of genome copies. Additionally, the existence of an unknown repair system (e.g. up-regulation, DNA lesions, DNA repair proteins) will be investigated. This will help gain knowledge on the DNA repair mechanisms in Archaea, and to better understand the limits of life.

Understanding the extent to which non-fastidious pathogenic bacteria can survive in extraterrestrial conditions will help to guarantee the safety of astronauts. Despite stringent decontamination protocols, terrestrial microorganisms were previously found to travel on the bodies of astronauts, on spaceships and equipment. This might create the possibility that these microorganisms adapt, grow and evolve in the new environment. In this study we assessed the adaptability of clinically relevant bacteria species which are able to grow on carbon-containing compounds identified in carbonaceous meteorites (Klebsiella pneumoniae, Burkholderia cepacia, Serratia marcescens and Pseudomonas aeruginosa). Previous work has shown that bacterial survival and growth under these conditions led to the modification of their cell envelope, in turn altering their pathogenic potential. We continued with this line of research and explored the survival of these bacterial species to a range of Martian conditions: i.e. desiccation, UVC and polychromatic UV irradiation, growth in the presence of perchlorates, growth on Martian soil and Martian atmospheric composition and pressure. Preliminary results showed that growth was enhanced by the addition of Mars Global simulant (mimicking Martian soil). Furthermore, only two of the strains, K. pneumoniae and S. marcescens are resistant to desiccation, up to 16 days. The UVC irradiation experiments have shown that the bacteria with the highest degree of survival are P. aeruginosa and S. marcescens. Likewise, the same two strains have shown higher survival rates compared to K. pneumoniae and B. cepacia following polychromatic UV irradiation, than from UVC irradiation. To understand the consequences of survival and growth under these conditions on virulence and immune recognition, we will analyse the response of immune cells exposed to bacteria adapted to Martian conditions. In addition, gene expression of the adapted bacteria will be further studied. This collaborative study between the DLR and the Radboud UMC, in the Netherlands will improve our insight into the adaptability of pathogenic bacteria to Martian conditions and their effects on virulence and immune recognition to anticipate on the potential risks of infection and inflammation associated with space-travel.

Mikroorganismen in marinen Untergrundsedimenten tragen wesentlich zur globalen Biomasse bei. Sedimente, die wärmer als 40 °C sind, machen dabei etwa die Hälfte des marinen Sedimentvolumens aus. Über die mikrobiellen Prozesse dieser Populationen in den nur schwer zugänglichen Habitaten ist bisher nur wenig bekannt. Jetzt gelang es, in bis zu 120 °C heißen Sedimenten unter dem Ozeanboden Leben nachzuweisen.

The ability of terrestrial life to survive in the Martian environment is of particular interest for both planetary protection measures and for future colonization endeavors. Many studies have examined bacterial spore survival and decontamination, however, little is known about fungal spore resistance properties. To understand the survival potential of fungal spores to Mars conditions, Aspergillus niger spores were sent on a 6.5-hour balloon flight to Earth’s stratosphere ( 38 km), where UV radiation and temperature conditions were similar to levels typical for equatorial Mars. Spores were carried inside the TREX unit – a sealed aluminum container filled with a Mars gas mixture – and flown aboard the MARSBOx balloon payload. Two different spore concentrations were tested on the TREX, exposed as dried samples in small quartz discs (20 µL). Discs were set in two different layers: a top layer exposed to direct UV radiation [M(+)UV, in a total dose of 1500 J/m²], and a bottom layer that was shielded from radiation [M(-)UV]. After the flight, fungal spore survival was determined by plating on agar and determining colony forming units (CFU/ml). A germination rate was calculated based on light microscopy analysis and revival metabolism assay was completed with resazurin dye. Results show that A. niger spores can survive Mars-like conditions [M(+)UV] for the 6.5 htime period tested in the middle stratosphere with only a 2-log reduction and slight delays in germination and revival metabolism compared to unflown lab controls. When shielded from UV, but exposed to Mars gas, pressure and temperature [M(-)UV] spore survival and germination were not affected. This study provides valuable insights on whether fungal spores could survive on Mars, and underscores the need for longer-duration exposure studies in Earth’s stratosphere to better characterize microbial resistance to space-related conditions.

In order to assess the performance of space environment models that are relevant to various impacts on (aero)space assets, the ISWAT Near-Earth Radiation and Plasma Environment community has been actively involved in engaging different communities together with the goal of addressing the issue from a systematic perspective. Information will be provided in first defining the essential space environment quantities (ESEQ) that are most relevant to the impacts (also directly measurable) and the corresponding essential effect quantities that are more easily understandable/useful for end-users. Metrics for measuring the model performance for different impacts/applications, uncertainties of models and observations, and methods of carrying out and archiving such model validation efforts/results for long-term performance assessment and tracking will be the focus of the presentation.

The radiation environment encountered in space differs in nature from that on Earth, consisting mostly of highly energetic ions from protons up to iron, resulting in radiation levels far exceeding the ones present on Earth for occupational radiation workers. Since the beginning of the space era the radiation exposure during space missions has been monitored with various passive and active radiation instruments. Also on-board the International Space Station (ISS) a number of area monitoring devices provide data related to the spatial and temporal variation of the radiation field in – and outside the ISS. The aim of the DOSIS 3D (2012 - ongoing) experiment is the measurement of the radiation environment within the European Columbus Laboratory of the ISS. These measurements are, on the one hand, performed with passive radiation detectors mounted at eleven locations within Columbus for the determination of the spatial distribution of the radiation field parameters and, on the other hand, with two active radiation detectors (DOSTEL) mounted at a fixed position inside Columbus for the determination of the temporal variation of the radiation field parameters. The talk will give an overview of the current results of the data evaluation performed for the passive and active radiation detectors for DOSIS 3D in the years 2012 to 2020 and further focus on the work in progress for data comparison with other passive and active radiation detector systems measuring on-board the ISS.

Whether terrestrial life can withstand the martian environment is of paramount interest for planetary protection measures and space exploration. To understand microbial survival potential in Mars-like conditions, several fungal and bacterial samples were launched in September 2019 on a large NASA scientific balloon flight to the middle stratosphere (∼38 km altitude) where radiation levels resembled values at the equatorial Mars surface. Fungal spores of Aspergillus niger and bacterial cells of Salinisphaera shabanensis, Staphylococcus capitis subsp. capitis, and Buttiauxella sp. MASE-IM-9 were launched inside the MARSBOx (Microbes in Atmosphere for Radiation, Survival, and Biological Outcomes Experiment) payload filled with an artificial martian atmosphere and pressure throughout the mission profile. The dried microorganisms were either exposed to full UV-VIS radiation (UV dose = 1148 kJ m⁻² ) or were shielded from radiation. After the 5-h stratospheric exposure, samples were assayed for survival and metabolic changes. Spores from the fungus A. niger and cells from the Gram-(–) bacterium S. shabanensis were the most resistant with a 2- and 4-log reduction, respectively. Exposed Buttiauxella sp. MASE-IM-9 was completely inactivated (both with and without UV exposure) and S. capitis subsp. capitis only survived the UV shielded experimental condition (3-log reduction). Our results underscore a wide variation in survival phenotypes of spacecraft associated microorganisms and support the hypothesis that pigmented fungi may be resistant to the martian surface if inadvertently delivered by spacecraft missions.

The use of high linear energy transfer (LET) ionizing radiation (IR) is progressively being incorporated in radiation therapy due to its precise dose localization and high relative biological effectiveness. At the same time, these benefits of particle radiation become a high risk for astronauts in the case of inevitable cosmic radiation exposure. Nonetheless, DNA Damage Response (DDR) activated via complex DNA damage in healthy tissue, occurring from such types of radiation, may be instrumental in the induction of various chronic and late effects. An approach to elucidating the possible underlying mechanisms is studying alterations in gene expression. To this end, we identified differentially expressed genes (DEGs) in high Z and high energy (HZE) particle-, γ-ray- and X-ray-exposed healthy human tissues, utilizing microarray data available in public repositories. Differential gene expression analysis (DGEA) was conducted using the R programming language. Consequently, four separate meta-analyses were conducted, after DEG lists were grouped depending on radiation type, radiation dose and time of collection post-irradiation. To highlight the biological background of each meta-analysis group, functional enrichment analysis and biological network construction were conducted. For HZE particle exposure at 8–24 h post-irradiation, the most interesting finding is the variety of DNA repair mechanisms that were downregulated, a fact that is probably correlated with complex DNA damage formation. Simultaneously, after X-ray exposure during the same hours after irradiation, DNA repair mechanisms continue to take place. Finally, in a further comparison of low- and high-LET radiation effects, the most prominent result is that autophagy mechanisms seem to persist and that adaptive immune induction seems to be present. Such bioinformatics approaches may aid in obtaining an overview of the cellular response to high-LET particles. Understanding these response mechanisms can consequently aid in the development of countermeasures for future space missions and ameliorate heavy ion treatments.

The aerospace environment has several sources of ionizing radiation. Exposure to this radiation is one of the natural hazards faced by aircrew, high-altitude pilots, frequent flyers, and commercial space travelers. Galactic cosmic rays (GCRs) and solar energetic particles (SEPs) almost always are the most important sources of ionizing radiation, particularly when traveling at or above commercial aviation altitudes (8 km or 26,000 ft). GCRs originate from outside the solar system and consist mostly of energetic protons with some alpha particles and a few heavier ions such as iron. SEPs originate on the Sun and are similar in composition to GCRs, being predominantly protons but with relatively fewer heavier ions. Recent measurements also suggest that secondary bremsstrahlung gamma-rays from precipitating Van Allen Belt relativistic electrons may also contribute dose at aviation altitudes. Regardless of their sources, charged particles transit Earth’s magnetosphere and interact with its atmosphere depending upon cutoff rigidity where the Earth’s magnetic field acts like a high-pass filter. During normal geomagnetic conditions, cutoff rigidity varies approximately inversely with geographic latitude; only particles with relatively high rigidity can make it to the atmosphere at latitudes near the equator, while even the lowest rigidity particles can enter the atmosphere at the geomagnetic poles. As a result, the largest primary radiation fluxes enter at high latitudes, with maxima surrounding the geomagnetic poles. We describe the ISWAT workshop results reviewing the state-of-art for aviation radiation monitoring and report the first results of the ARMAS Dual Monitor project demonstrating 24/7 monitoring as well as improved understanding of the particles and processes that create the aviation radiation environment.

The EDEN ISS greenhouse is a confined mobile test facility in Antarctica for the development and optimization of new plant cultivation techniques for future space programs. The EDEN ISS greenhouse was in operation from February to November 2018 for fresh food production for the overwintering crew at the German Antarctic Neumayer III station. During the nine months of operation, samples from the different plants, from the nutrition solution of the aeroponic planting system and from diverse surfaces within the three different compartments of the container were taken (future exploration greenhouse, service section, cold porch). Quantity as well as diversity of microorganisms was examined by cultivation. For identification, 16S rRNA gene sequencing was performed for the isolated prokaryotic organisms. In case of the plant samples, microbial quantities were in a range from 102 to 104 colony forming units per gram plant material. Compared to plants purchased from a German grocery, the produce hosted much more microorganisms than the EDEN ISS plants. The EDEN ISS plant samples contained mainly fungi and a few, most probably harmless bacteria. Most likely due to the used cultivation approach, Archaea were not found in the samples. The bioburden in the nutrition solutions increased constantly over time but never reached critical values. The surface samples revealed high differences in the microbial burden between the greenhouse part of the container and the service section and cold porch part. However, the numbers of organisms (bacteria and fungi) found in the planted greenhouse were still not critical. The microbial loaded surfaces showed strong temporal as well as spatial fluctuations. In samples of the nutrition solution and the surface, the amount of bacteria exceeded the amount of fungi by many times. The most abundant bacterial phyla were Firmicutes and Actinobacteria. These phyla include plant- and human-associated bacterial species. In general, there is a low risk of infection due to microbial contamination according to the results of this study. The metagenomic analysis of the EDENISS samples is ongoing.

The use of high linear energy (LET) ionizing radiation (IR) is progressively being incorporated in radiation therapy (RT) due to its precise dose localization and high relative biological effectiveness. At the same time, these benefits of particle radiation become a high risk for astronauts in the case of inevitable long-term cosmic radiation exposure. Nonetheless, DNA Damage Response (DDR) activated via complex DNA damage on healthy tissue, occurring from such types of radiation, may be instrumental in the induction of various chronic and late effects. A method of approach in understanding the possible underlying mechanisms, is studying alterations in gene expression. To this end we identified Differentially Expressed Genes (DEGs) in IR-exposed healthy human tissue, utilizing microarray data available in public repositories. DEG analysis was conducted using R programming language. Consequently, through functional enrichment and biological network analysis, we identified biological pathways and processes implicated in DDR. By comparing low and high-LET radiation effects, our primary results indicate the induction of a differential biological response for high-LET, like an enhanced inflammatory response.In addition, patterns of DNA repair are substantially distinct compared to low-LET. Finally, we expanded our study in search of possible comorbidities for HZE particle exposure. Pathway enrichment analysis suggests the involvement of mechanisms, tightly correlated with neurodegenerative disorders like amyloid fibrils formation. Regarding blood tissue, platelet activation signaling was found, upholding the connection to cardiovascular disease. This holistic bioinformatics approach revealed cellular trends towards inflammation and degeneration which might be central to the development of late effects of high-LET radiation exposure. It can contribute to the identification of molecular targets for effective countermeasures.

BACKGROUND Radiation and reduced gravity impose a major burden on health and performance during human spaceflight. While radiation increases cancer risk and limits tissue regeneration, reduced gravity predisposes to musculoskeletal and cardiovascular deconditioning. Deconditioning could conceivably limit the recovery from radiation damage. Our aim was to develop a terrestrial ex vivo model that could be utilized to study the effect of simulated reduced gravity using head-down-tilt bed-rest on repair of ionizing-radiation-induced DNA damage.

Das Targeting des MEK-Proteins in Krebszellen führt in der Regel zu einer erworbenen Resistenz gegen MEK-Inhibitoren und zur Aktivierung des überlebenswichtigen Proteins Akt. Da sowohl MEK als auch Akt Clienten des Hsp90-Chaperonsystems sind, untersucht die vorliegende Arbeit die Reaktionen von bestrahlten Lungenkarzinom- (A549) und Glioblastom- (SNB19) Zelllinien auf eine kombinierte MEK- und Hsp90-Hemmung. Unerwarteterweise verbesserte der 24 h vor der Bestrahlung verabreichte MEK-Inhibitor PD184352 das Zellüberleben durch Hochregulation von MEK und Erk1/2, aber auch von Akt. Im Gegensatz dazu reduzierte PD184352, das 1 h vor der Bestrahlung zugegeben wurde, die Expression von Erk stark und regulierte Akt in beiden Zelllinien nicht hoch. Als Ergebnis verstärkte der MEK-Inhibitor die radiosensibilisierende Wirkung des Hsp90-Inhibitors NVP-AUY922 in Glioblastomzellen (SNB19)., Targeting MEK protein in cancer cells usually leads to acquired resistance to MEK inhibitors and activation of the prosurvival protein Akt. Since both MEK and Akt are clients of the Hsp90 chaperone system, the present study explores the responses of irradiated lung carcinoma A549 and glioblastoma SNB19 cell lines to combined MEK and Hsp90 inhibition. Unexpectedly, the MEK inhibitor PD184352 administered 24 h prior to irradiation, enhanced cell survival through upregulation of not only MEK and Erk1/2 but also of Akt. In contrast, PD184352 added 1 h before irradiation strongly reduced the expression of Erk and did not upregulate Akt in both cell lines. As a result, the MEK inhibitor increased the radiosensitizing effect of the Hsp90 inhibitor NVP-AUY922 in glioblastoma SNB19 cells.

Exposure of aircrew to cosmic radiation has been recognized as an occupational health risk for several decades. Based on the recommendations by the International Commission on Radiological Protection (ICRP), many countries and their aviation authorities, respectively have either stipulated legal radiation protection regulations, e.g., in the European Union or issued corresponding advisory circulars, e.g., in the United States of America. Additional sources of ionizing and non-ionizing radiation, e.g., due to weather phenomena have been identified and discussed in the scientific literature in recent years. This article gives an overview of the different generally recognized sources due to weather as well as space weather phenomena that contribute to radiation exposure in the atmosphere and the associated radiation effects that might pose a risk to aviation safety at large, including effects on human health and avionics. Furthermore, potential mitigation measures for several radiation sources and the prerequisites for their use are discussed.

Among the celestial bodies in the Solar System, Mars currently represents the main target for the search for life beyond Earth. However, its surface is constantly exposed to high doses of cosmic rays (CRs) that may pose a threat to any biological system. For this reason, investigations into the limits of resistance of life to space relevant radiation is fundamental to speculate on the chance of finding extraterrestrial organisms on Mars. In the present work, as part of the STARLIFE project, the responses of dried colonies of the black fungus Cryomyces antarcticus Culture Collection of Fungi from Extreme Environments (CCFEE) 515 to the exposure to accelerated iron (LET: 200 keV/μm) ions, which mimic part of CRs spectrum, were investigated. Samples were exposed to the iron ions up to 1000 Gy in the presence of Martian regolith analogues. Our results showed an extraordinary resistance of the fungus in terms of survival, recovery of metabolic activity and DNA integrity. These experiments give new insights into the survival probability of possible terrestrial-like life forms on the present or past Martian surface and shallow subsurface environments.

Microorganisms are employed to mine economically important elements from rocks, including the rare earth elements (REEs), used in electronic industries and alloy production. We carried out a mining experiment on the International Space Station to test hypotheses on the bioleaching of REEs from basaltic rock in microgravity and simulated Mars and Earth gravities using three microorganisms and a purposely designed biomining reactor. Sphingomonas desiccabilis enhanced mean leached concentrations of REEs compared to non-biological controls in all gravity conditions. No significant difference in final yields was observed between gravity conditions, showing the efficacy of the process under different gravity regimens. Bacillus subtilis exhibited a reduction in bioleaching efficacy and Cupriavidus metallidurans showed no difference compared to non-biological controls, showing the microbial specificity of the process, as on Earth. These data demonstrate the potential for space biomining and the principles of a reactor to advance human industry and mining beyond Earth., Rare earth elements are used in electronics, but increase in demand could lead to low supply. Here the authors conduct experiments on the International Space Station and show microbes can extract rare elements from rocks at low gravity, a finding that could extend mining potential to other planets.

Antimicrobial surfaces are a well suited technology to prevent and reduce microbial loads in sensitive areas, where high humidity and temperature levels are causing increased microbial loads. These can endanger human health, health of organisms e.g. in bioregenerative life-support systems as well as technical equipment. Antimicrobial surfaces are preventively beneficial • in spaceflight – e.g. in confined environments in LEO and during exploration activities, to support breeding activities of e.g. algae in bioreactors and for biological experiments, and furthermore to meet the COSPAR planetary protection policy • as well as also on Earth - in hygiene areas during medical activities and food handling, in swimming baths, bathrooms, public transportation, submarines, greenhouses etc. For its dedicated use in space as well as on Earth, antimicrobial surfaces must be free of any toxic substance, otherwise higher non-target organisms would be affected. That means, that synthetic chemicals, silver, copper etc., as used until now, are not a suited solution - which in addition might lead to resistances of the bacteria to these toxic substances and are acting rather unspecific. A suited alternative to overcome these problems are bioinspired technologies as using antimicrobial peptides from nature (e.g. from frog skin etc.), immobilized on surfaces. High flexibility concerning the microbial target, acting specifically, low toxicity and an absence of resistances are the main advantages. As a logical step, the goal of the ESA-funded project BALS (Bioinspired antimicrobial lacquer for space) was the development of a new innovative antimicrobial acting lacquer based on peptides. Project partners were OHB System, Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM) (both Bremen, Germany) as well as the German Aerospace Center, Institute of Aerospace Medicine (Cologne, Germany). The developed antimicrobial lacquer with immobilized peptides showed an antimicrobial activity against S. cohnii and E. coli, compared to a reference lacquer without peptides. Its adhesion strength on space relevant substrates was demonstrated in a ECSS-Q-70-13A-test series, measuring the peel and pull-off strength using pressure-sensitive tapes. In addition, the absence of effects on higher organisms and the environment was shown in a laboratory aquatic biological multispecies test system (AquaHab®). With the successful demonstration of feasibility and use (TRL 4) of such a bioinspired antimicrobial lacquer and including these promising test results, all preconditions are now given for the further development and qualification until a full commercial exploitation, ready to be used in application fields in space and on Earth.

Ignicoccus hospitalis es un organismo extremófilo que pertenece al dominio Archaea. Se caracteriza por crecer bajo condiciones muy específicas, puesto que es un microbio hipertermófilo, estrictamente anaerobio y quimiolitoautótrofo; metaboliza azufre elemental por reducción y utiliza CO2 como fuente de carbono, fijándolo por medio de una ruta única en su tipo que fue descrita recientemente por primera vez. Estas características biológicas están directamente relacionadas a las condiciones físicoquímicas propias del ambiente de donde fue aislado, un sistema submarino de fumarolas hidrotermales en la cordillera Kolbeinsey ubicada al norte de Islandia.

Human exploration of the Moon is associated with substantial risks to astronauts from space radiation. On the surface of the Moon, this consists of the chronic exposure to galactic cosmic rays and sporadic solar particle events. The interaction of this radiation field with the lunar soil leads to a third component that consists of neutral particles, i.e., neutrons and gamma radiation. The Lunar Lander Neutrons and Dosimetry experiment aboard China's Chang'E 4 lander has made the first ever measurements of the radiation exposure to both charged and neutral particles on the lunar surface. We measured an average total absorbed dose rate in silicon of 13.2 ± 1 μGy/hour and a neutral particle dose rate of 3.1 ± 0.5 μGy/hour.

The deep-sea anoxic brines of the Red Sea include some of the most extreme locations on Earth (1). Their unique combination of high salinity, high-pressure, anoxia, and varying levels of hydrothermal input make them a valuable source of new polyextremophilic microbes and for exploring the limits of life. They have recently been proposed as relevant terrestrial analogues and flagged for future Astrobiological-based research (2). Among these proposals, exposure experiments with representatives of new taxa was seen as one of the top priorities. Current knowledge on the capability of (facultative) anaerobic microbes to withstand extraterrestrial conditions is still very sparse and is one of the main goals of the project MEXEM (Mars EXposed Extremophiles Mixture). Here we report the results of exposure experiments performed with Salinisphaera shabanensis, a facultative anaerobic, halophilic bacterium isolated from one of the Red Sea brines (3). Our results show that this bacterium is facultative anaerobic, radiation tolerant and can survive long periods of desiccation, making it a promising new model organism for Astrobiology. Comparative studies with other species within this genus (including thermophilic, alkaliphilic, and non-extremophilic ones) should prove particularly insightful in the near future.

Space exposure experiments from the last 15 years have unexpectedly shown that several terrestrial organisms, including some multi-cellular species, are able to survive in open space without protection. The robustness of bdelloid rotifers suggests that these tiny creatures can possibly be added to the still restricted list of animals that can deal with the exposure to harsh condition of space. Bdelloids are one of the smallest animals on Earth. Living all over the world, mostly in semi-terrestrial environments, they appear to be extremely stress tolerant. Their desiccation tolerance at any stage of their life cycle is known to confer tolerance to a variety of stresses including high doses of radiation and freezing. In addition, they constitute a major scandal in evolutionary biology due to the putative absence of sexual reproduction for at least 60 million years. Adineta vaga, with its unique characteristics and a draft genome available, was selected by ESA (European Space Agency) as a model system to study extreme resistance of organisms exposed to space environment. In this manuscript, we documented the resistance of desiccated A. vaga individuals exposed to increasing doses of X-ray, protons and Fe ions. Consequences of exposure to different sources of radiation were investigated in regard to the cellular type including somatic (survival assay) and germinal cells (fertility assay). Then, the capacity of A. vaga individuals to repair DNA DSB induced by different source of radiation was investigated. Bdelloid rotifers represent a promising model in order to investigate damage induced by high or low LET radiation. The possibility of exposure both on hydrated or desiccated specimens may help to decipher contribution of direct and indirect radiation damage on biological processes. Results achieved through this study consolidate our knowledge about the radioresistance of A. vaga and improve our capacity to compare extreme resistance against radiation among living organisms including metazoan.

One of the primary current astrobiological goals is to understand the limits of microbial resistance to extraterrestrial conditions. Much attention is paid to ionizing radiation, since it can prevent the preservation and spread of life outside the Earth. The aim of this research was to study the impact of accelerated He ions (150 MeV/n, up to 1 kGy) as a component of the galactic cosmic rays on the black fungus C. antarcticus when mixed with Antarctic sandstones&mdash, the substratum of its natural habitat&mdash, and two Martian regolith simulants, which mimics two different evolutionary stages of Mars. The high dose of 1 kGy was used to assess the effect of dose accumulation in dormant cells within minerals, under long-term irradiation estimated on a geological time scale. The data obtained suggests that viable Earth-like microorganisms can be preserved in the dormant state in the near-surface scenario for approximately 322,000 and 110,000 Earth years within Martian regolith that mimic early and present Mars environmental conditions, respectively. In addition, the results of the study indicate the possibility of maintaining traces within regolith, as demonstrated by the identification of melanin pigments through UltraViolet-visible (UV-vis) spectrophotometric approach.

Microorganisms perform countless tasks on Earth and they are expected to be essential for human space exploration. Despite the interest in the responses of bacteria to space conditions, the findings on the effects of microgravity have been contradictory, while the effects of Martian gravity are nearly unknown. We performed the ESA BioRock experiment on the International Space Station to study microbe-mineral interactions in microgravity, simulated Mars gravity and simulated Earth gravity, as well as in ground gravity controls, with three bacterial species: Sphingomonas desiccabilis, Bacillus subtilis, and Cupriavidus metallidurans. To our knowledge, this was the first experiment to study simulated Martian gravity on bacteria using a space platform. Here, we tested the hypothesis that different gravity regimens can influence the final cell concentrations achieved after a multi-week period in space. Despite the different sedimentation rates predicted, we found no significant differences in final cell counts and optical densities between the three gravity regimens on the ISS. This suggests that possible gravity-related effects on bacterial growth were overcome by the end of the experiment. The results indicate that microbial-supported bioproduction and life support systems can be effectively performed in space (e.g., Mars), as on Earth.

In this chapter, the key technologies and the instrumentation required for the subsurface exploration of ocean worlds are discussed. The focus is laid on Jupiter’s moon Europa and Saturn’s moon Enceladus because they have the highest potential for such missions in the near future. The exploration of their oceans requires landing on the surface, penetrating the thick ice shell with an ice-penetrating probe, and probably diving with an underwater vehicle through dozens of kilometers of water to the ocean floor, to have the chance to find life, if it exists. Technologically, such missions are extremely challenging. The required key technologies include power generation, communications, pressure resistance, radiation hardness, corrosion protection, navigation, miniaturization, autonomy, and sterilization and cleaning. Simpler mission concepts involve impactors and penetrators or – in the case of Enceladus – plume-fly-through missions.

The radiation environment in free space and the related radiation exposure is seen as one of the main health detriments for future long-duration human exploration missions beyond Low Earth Orbit (LEO). The steady flux of energetic particles in the galactic cosmic radiation (GCR) produces a low dose-rate radiation exposure, which is heavily influenced by several factors including the solar cycle, the presence of an atmosphere, relevant magnetic fields (as on Earth) and of course by the relevant spacecraft shielding. Investigations of the GCR variations over the course of a solar cycle provide valuable data for exploration mission planning and for the determination of the radiation load received due to the GCR environment. Within the current work these investigations have been performed applying three datasets generated on board the International Space Station (ISS) with the DOSTEL instruments in the frame of the DOSIS and DOSIS-3D projects, with the CRaTER instrument in a Moon orbit and with the MSL-RAD instrument on the way to and on the surface of Mars. To derive GCR dose contributions on board the ISS two procedures have been developed separating the contributions from GCR from passing’s through the South Atlantic Anomaly (SAA), as well as ways to extrapolate the GCR dose measured on board the ISS to free space based on various ranges of the McIlwain L-shell parameter. At the end we provide a dataset spanning the timeframe for GCR measurements on the ISS (2009 – 2011 & 2012 – 2019), Moon (2009 – 2019) and Mars (2012 – 2019), thereby covering the time span from the deep minimum of solar cycle 23, the ascending phase and maximum of solar cycle 24, and the descending phase of cycle 24, which is ongoing at the time of this writing.

Hintergrund Augenveränderungen bei Astronautinnen und Astronauten, insbesondere das „spaceflight associated neuro-ocular syndrome“ (SANS), sind eine medizinische Herausforderung, für die es bisher noch keine geeignete Präventionsmaßnahme gibt. Bei längeren Weltraummissionen z. B. zu Mond und Mars könnten SANS und die strahlenbedingte Katarakt die Gesundheit und Leistungsfähigkeit der Crews und den Erfolg der Missionen gefährden. Für mechanistische Studien und Entwicklung präventiver Verfahren sind geeignete terrestrische Modelle erforderlich. Ziele der Arbeit Es soll eine Übersicht über den aktuellsten Forschungsstand und künftige Bestrebungen in der Weltraummedizin gegeben werden. Material und Methoden Es erfolgt eine Analyse der relevanten Veröffentlichungen anhand von PubMed. Ergebnisse In den Bettruhestudien des Instituts für Luft- und Raumfahrtmedizin des DLR (Deutsches Zentrum für Luft- und Raumfahrt) konnte gezeigt werden, dass strikte Bettruhe in −6° Kopftieflage Veränderungen wie bei SANS auf der Erde reproduzieren kann. Das Modell inklusive der Erzeugung von Papillenödemen wird eingesetzt, um die Wirkung künstlicher Schwerkraft mittels Kurzarmzentrifugation als präventive Maßnahme zu untersuchen. Die einzigartige Forschungseinrichtung :envihab bietet die Möglichkeit, während der Bettruhestudien auch die Umgebungsbedingungen wie auf der Internationalen Raumstation zu simulieren. Schlussfolgerung Künftige Bettruhestudien in Kopftieflage sollen dazu dienen, Verfahren für die Prävention von SANS systematisch zu prüfen. Dies wäre unter realen Weltraumbedingungen schwer zu realisieren. Durch eine enge Kooperation von Weltraummedizin und terrestrischer Ophthalmologie soll diese Forschung auch Patienten auf der Erde zugutekommen.

Carotenoids are promising targets in our quest to search for life on Mars due to their biogenic origin and easy detection by Raman spectroscopy, especially with a 532 nm excitation thanks to resonance effects. Ionizing radiations reaching the surface and subsurface of Mars are however detrimental for the long-term preservation of biomolecules. We show here that desiccation can protect carotenoid Raman signatures in the desert cyanobacterium Chroococcidiopsis sp. CCMEE 029 even after high-dose gamma irradiation. Indeed, while the height of the carotenoids Raman peaks was considerably reduced in hydrated cells exposed to gamma irradiation, it remained stable in dried cells irradiated with the highest tested dose of 113 kGy of gamma rays, losing only 15-20% of its non-irradiated intensity. Interestingly, even though the carotenoid Raman signal of hydrated cells lost 90% of its non-irradiated intensity, it was still detectable after exposure to 113 kGy of gamma rays. These results add insights into the preservation potential and detectability limit of carotenoid-like molecules on Mars over a prolonged period of time and are crucial in supporting future missions carrying Raman spectrometers to Mars&rsquo, surface.

To understand the mechanisms of disturbed differentiation and development by radiation, murine CGR8 embryonic stem cells (mESCs) were exposed to ionizing radiation and differentiated by forming embryoid bodies (EBs). The colony forming ability test was applied for survival and the MTT test for viability determination after X-irradiation. Cell cycle progression was determined by flow cytometry of propidium iodide-stained cells, and DNA double strand break (DSB) induction and repair by &gamma, H2AX immunofluorescence. The radiosensitivity of mESCs was slightly higher compared to the murine osteoblast cell line OCT-1. The viability 72 h after X-irradiation decreased dose-dependently and was higher in the presence of leukemia inhibitory factor (LIF). Cells exposed to 2 or 7 Gy underwent a transient G2 arrest. X-irradiation induced &gamma, H2AX foci and they disappeared within 72 h. After 72 h of X-ray exposure, RNA was isolated and analyzed using genome-wide microarrays. The gene expression analysis revealed amongst others a regulation of developmental genes (Ada, Baz1a, Calcoco2, Htra1, Nefh, S100a6 and Rassf6), downregulation of genes involved in glycolysis and pyruvate metabolism whereas upregulation of genes related to the p53 signaling pathway. X-irradiated mESCs formed EBs and differentiated toward cardiomyocytes but their beating frequencies were lower compared to EBs from unirradiated cells. These results suggest that X-irradiation of mESCs deregulate genes related to the developmental process. The most significant biological processes found to be altered by X-irradiation in mESCs were the development of cardiovascular, nervous, circulatory and renal system. These results may explain the X-irradiation induced-embryonic lethality and malformations observed in animal studies.

The filamentous fungus Aspergillus niger is one of the main contaminants of the International Space Station (ISS). It forms highly pigmented, airborne spores that have thick cell walls and low metabolic activity, enabling them to withstand harsh conditions and colonize spacecraft surfaces. Whether A. niger spores are resistant to space radiation, and to what extent, is not yet known. In this study, spore suspensions of a wild-type and three mutant strains (with defects in pigmentation, DNA repair, and polar growth control) were exposed to X-rays, cosmic radiation (helium- and iron-ions) and UV-C (254 nm). To assess the level of resistance and survival limits of fungal spores in a long-term interplanetary mission scenario, we tested radiation doses up to 1000 Gy and 4000 J/m2. For comparison, a 360-day round-trip to Mars yields a dose of 0.66 ± 0.12 Gy. Overall, wild-type spores of A. niger were able to withstand high doses of X-ray (LD90 = 360 Gy) and cosmic radiation (helium-ion LD90 = 500 Gy; and iron-ion LD90 = 100 Gy). Drying the spores before irradiation made them more susceptible toward X-ray radiation. Notably, A. niger spores are highly resistant to UV-C radiation (LD90 = 1038 J/m2), which is significantly higher than that of other radiation-resistant microorganisms (e.g., Deinococcus radiodurans). In all strains, UV-C treated spores (1000 J/m2) were shown to have decreased biofilm formation (81% reduction in wild-type spores). This study suggests that A. niger spores might not be easily inactivated by exposure to space radiation alone and that current planetary protection guidelines should be revisited, considering the high resistance of fungal spores.