Space Radiation Research Articles

Articular cartilage loss is an unmitigated risk of human spaceflight.

Microgravity and space radiation are hazards of spaceflight that have deleterious effects on articular cartilage. Since it is not widely monitored or protected through dedicated countermeasures, articular cartilage loss is an unmitigated risk of human spaceflight. Spaceflight-induced cartilage loss will affect an astronaut's performance during a mission and long-term health after a mission. Addressing concerns for cartilage health will be critical to the continued safe and successful exploration of space.

Pharmacological Innovations in Space: Challenges and Future Perspectives.

Since the first human experience in space, the interest in space research and medicine to explore universe is growing day by day. The extreme space conditions mainly radiation and microgravity effects on human physiology, antimicrobial susceptibility, and efficacy, safety, and stability of drugs. Therefore, the aim of this review is to address the impact of extreme space conditions, mainly microgravity and radiation, on human physiology and highlights the need for future approaches by evaluating the effectiveness of strategies to prevent or mitigate health problems. Published papers and NASA technical documents were searched in Pubmed and Google Scholar databases using the keywords ''antimicrobial susceptibility or drug resistance or drug stability or innovations or pharmacokinetic or pharmacodynamics'' and ''radiation or microgravity or space environments or space medicine or space pharmacy'' to prepare this review. In this review, the challenges regarding physiological effects and drug-related problems are examined through the evaluation of extreme conditions in space. Medications used in spaceflight are summarized, and the role of pharmacists specializing in space medicine is briefly explained. Last but not least, to overcome the aforementioned issues, novel approaches have been addressed, such as personalised treatments, development of space-resistant formulations and various microbial applications. Further research in the space medicine is required to facilitate the safe and healthy travel of humans to the Moon, Mars and other extraterrestrial destinations. One bear in mind that space research will contribute not only to the exploration of the universe, but also to the advancement of health and technological discoveries on Earth.

Statistical Analysis of LEO and GEO Satellite Anomalies and Space Radiation

Exposure to space radiation substantially degrades satellite systems, provoking severe partial or, in some extreme cases, total failures. Electrostatic discharges (ESD), single event latch-up (SEL), and single event upsets (SEU) are among the most frequent causes of those reported satellite anomalies. The impact of space radiation dose on satellite equipment has been studied in-depth. This study conducts a statistical analysis to explore the relationships between low-Earth orbit (LEO) and geostationary orbit (GEO) satellite anomalies and particle concentrations, solar and geomagnetic activity in the period 2010–2022. Through a monthly and daily timescale analysis, the present work explores the temporal response of space disturbances on satellite systems and the periods when satellites are vulnerable to those disturbances.

Space Travel: The Radiation and Microgravity Effects on the Cardiovascular System.

Space flight modulates the functions of the cardiovascular system. The exposure to space conditions can alter the cerebral blood flow, as well as the venous return. Anemia, cardiac output changes, and increased activity of the sympathetic nervous system can also be seen. Understanding cardiac changes prepares astronauts for both better in-flight adaptations and long-term protection against cardiovascular diseases. The heart could undergo radio-degenerative effects when exposed to space radiation, increasing the risk of cardiovascular diseases in the long run. A high frequency of arrhythmias, such as ventricular/atrial premature complexes, have been reported during the Gemini and Apollo missions. Additionally, microgravity can lead to progressive degeneration of the myocytes and muscle atrophy with altered gene expression and calcium handling, along with impaired contractility. This review summarizes the potential cardiovascular effects of spaceflight and prevention measures.

Space Environmental Effects on Multifunctional Radiation Shielding Materials

AbstractThe two primary material requirements for a crewed habitat or spacecraft to operate beyond low earth orbit (LEO) include effective radiation shielding against the space radiation and secondary neutron environment and sufficient structural and thermal integrity. In this context it is mandatory to study the effect of long duration space environment on any proposed multifunctional radiation shielding material. In this paper we discuss two radiation shielding composite architectures and their long duration performance in LEO. Samples were flown on NASA's The Materials International Space Station Experiment (MISSE) platform and their structural, optical, and radiation shielding capabilities were characterized pre and post flight. Results showed composite architecture can be key in determining expected damage irrespective of sample placement orientation on the space station. A surface layer with a protective or sacrificial coating can be instrumental in minimizing property degradation even when exposed to orientations with high estimated sun hours and high fluence of atomic oxygen.

A Dual-Band Leaky Wave Antenna With Dual-Bi-Directional Continuous Beam Scanning for Large Space Radiation Coverage

A Dual-Band Leaky Wave Antenna With Dual-Bi-Directional Continuous Beam Scanning for Large Space Radiation Coverage

Predicting the Energy Spectra of Solar Energetic Particles with a Machine Learning Regression Algorithm

Solar energetic particles (SEPs) are a major source of space radiation, especially within the inner heliosphere. These particles, originating from solar flares and coronal mass ejections (CMEs), propagate primarily along interplanetary magnetic fields. The energy spectra of SEP events are crucial for assessing radiation effects and understanding the acceleration and propagation mechanisms in their source regions. In this study, we employed a decision tree regression algorithm with cost complexity pruning to predict SEP energy spectra, including peak flux and integral fluence spectra. This approach uses only solar flares, CMEs, and solar wind data as input parameters and demonstrates strong performance to accurately predict SEP spectra. This method holds significant real-time application value for monitoring and forecasting radiation risks in both deep space and near-Earth environments.

Applications, Limitations, and Considerations of Clinical Trials in a Dish

Recent advancements in biotechnology forged the path for clinical trials in dish (CTiDs) to advance as a popular method of experimentation in biomedicine. CTiDs play a fundamental role in translational research through technologies such as induced pluripotent stem cells, whole genome sequencing, and organs-on-a-chip. In this review, we explore advancements that enable these CTiD biotechnologies and their applications in animal testing, disease modeling, and space radiation technologies. Furthermore, this review dissects the advantages and disadvantages of CTiDs, as well as their regulatory considerations. Lastly, we evaluate the challenges that CTiDs pose and the role of CTiDs in future experimentation.

Statistical study of the peak and fluence spectra of solar energetic particles observed over four solar cycles

Context. Solar energetic particles (SEPs) are an important space radiation source, especially for the space weather environment in the inner heliosphere. The energy spectrum of SEP events is crucial both for evaluating their radiation effects and for understanding their acceleration process at the source region, along with their propagation mechanism. Aims. In this work, we investigate the properties of the SEP peak flux spectra and the fluence spectra and their potential formation mechanisms using statistical methods. We aim to advance our understanding of SEP acceleration and propagation mechanisms. Methods. Employing a dataset from the European Space Agency’s Solar Energetic Particle Environment Modelling (SEPEM) program, we obtained and fit the peak-flux and fluence proton spectra of more than a hundred SEP events from 1974 to 2018. We analyzed the relationship among the solar activity, X-ray peak intensity of solar flares, and the SEP’s spectral parameters. Results. Based on the assumption that the initial spectrum of accelerated SEPs generally displays a power-law distribution and that the diffusion coefficient has a power-law dependence on the particle energy, we can assess both the source and propagation properties using the observed SEP event peak flux and fluence energy spectra. We confirm that the spectral properties of SEPs are influenced by the solar source and the interplanetary conditions, whereas their transportation process can be influenced by different phases of solar cycle. Conclusions. This study provides an observational perspective on the double power-law spectral characteristics of the SEP energy spectra, revealing their correlation with the adiabatic cooling and diffusion processes during the particle propagation from the Sun to the observer. This result contributes to forging a deeper understanding of the acceleration and propagation of SEP events, in particular, the possible origins of the double power law.

Spaceborne particle identification platform and its application based on convolutional neural network

The identification of particle types in space radiation particle detection is a problem of great concern in scientific research and engineering applications. At present, the particle types are mainly identified by the difference in energy deposition of particles in the sensor, the difference in waveform in the sensor, the flight time and energy of particles, and the difference in the deflection path of particles in the electric field, such as traditional telescope detectors, particle pulse waveform analysis, flight time TOF system and electrostatic analyzer. However, the current on-orbit particle identification logic is relatively simple and the identification accuracy is limited. Convolutional neural networks have powerful target classification capabilities and are good at capturing and extracting target feature details, which can improve the accuracy of particle energy measurement and identification. Based on the environment commonly used in space environment detection payloads, this paper proposes a method for building an on-orbit convolutional neural network particle identification platform to achieve particle type identification. The platform first constructs a multi-dimensional input data set, completes the model training and weight derivation with the help of the software platform, and completes the waveform inference and data set expansion through the hardware platform. The established identification platform is used to train and test the neutron and gamma waveform data obtained in actual tests, and the accuracy of the identification of the software and hardware platforms is analyzed, completing the verification of the platform. The establishment and application of this platform provides a new idea and method for particle measurement and identification in future space environment detection, and has strong engineering practice significance.

Review of Photodetectors for Space Lidars

Photodetectors play a critical role in space lidars designed for scientific investigations from orbit around planetary bodies. The detectors must be highly sensitive due to the long range of measurements and tight constraints on the size, weight, and power of the instrument. The detectors must also be space radiation tolerant over multi-year mission lifetimes with no significant performance degradation. Early space lidars used diode-pumped Nd:YAG lasers with a single beam for range and atmospheric backscattering measurements at 1064 nm or its frequency harmonics. The photodetectors used were single-element photomultiplier tubes and infrared performance-enhanced silicon avalanche photodiodes. Space lidars have advanced to multiple beams for surface topographic mapping and active infrared spectroscopic measurements of atmospheric species and surface composition, which demand increased performance and new capabilities for lidar detectors. Higher sensitivity detectors are required so that multi-beam and multi-wavelength measurements can be performed without increasing the laser and instrument power. Pixelated photodetectors are needed so that a single detector assembly can be used for simultaneous multi-channel measurements. Photon-counting photodetectors are needed for active spectroscopy measurements from short-wave infrared to mid-wave infrared. HgCdTe avalanche photodiode arrays have emerged recently as a promising technology to fill these needs. This paper gives a review of the photodetectors used in past and present lidars and the development and outlook of HgCdTe APD arrays for future space lidars.

The single event upset hardened design of spin transfer torque magnetic random access memory read circuits at 40 nm technology

With the advancement of technology nodes, the challenging space radiation environment poses a significant threat to memory reliability. Spin transfer torque magnetic random access memory (STT-MRAM) is a formidable candidate for non-volatile memory for space applications due to its advantages of non-volatility, durability, speed and compatibility with CMOS technology. Although the STT-MRAM memory unit magnetic tunnel junction (MTJ) is naturally immune to radiation effects, the single event upset (SEU) affects the peripheral circuitry. A radiation-hardened circuit is proposed, which theoretically does not have ‘0' upset nodes and automatically recovers from ‘1' upset. Moreover, the circuit's radiation-hardened performance was corroborated through hybrid simulation utilizing 40-nm technology. The findings of this investigation hold significance for the use of space radiation-hardened STT-MRAM.

Radiation exposure of astronauts following an intense solar particle event: analysis and comparison of doses in male and female voxel phantoms.

According to NASA's plans, a human travel to the Moon is planned by the end of 2025 with the Artemis II mission, and humans should land on the Moon again in 2026. Exposure to space radiation is one of the main risks for the crew members; while for these short missions the doses from galactic cosmic rays would be relatively low, the possible occurrence of an intense solar particle event (SPE) represents a major concern, especially considering that in 2025 the Sun activity will be at its peak. Quantifying the amount and the effects of such exposure is therefore crucial, to identify shielding conditions that allow respecting the dose limits established by the various space agencies. By exploiting an interface between the BIANCA biophysical model and the FLUKA Monte Carlo radiation transport code, in this work we implemented a male and a female voxel phantom and we calculated absorbed doses and Gy-Eq doses in the various tissues/organs, as well as effective doses, following exposure to the August 1972 SPE, the most intense event of the modern era. The calculations were performed respect the organ dose limits for 30 d missions. A detailed comparison between male and female doses was then carried out, also considering that the Artemis II crew will include a woman. The results showed that female doses tend to be higher than male doses, especially with light shielding. This should be taken into account in mission design, also considering that, in a typical lunar mission, up to 15% of time may be spent in extra-vehicular activities, and thus with light shielding. More generally, this work outlines the importance of performing separate calculations for male and female astronauts when dealing with radiation doses and effects.

Anthocyanin can improve the survival of rice seeds from solar light outside the international space station

A purple-pigmented (purple) rice seeds containing an anthocyanin, a major class of flavonoids, and their isogenic non-pigmented (white) seeds were exposed outside of the international space station (ISS) to evaluate the impact of anthocyanin on seed viability in space. The rice seeds were placed in sample plates at the exposed facility of ISS for 440 days, with the bottom layer seeds exposed to space radiation and the top layer seeds exposed to both solar light and space radiation. Though the seed weight of both purple and white seeds decreased after exposure to outer space, growth percentages after germination of purple and white seeds in the top layer were 55 and 15 %, respectively, compared to those in the bottom layer 100 and 70 %, respectively. RNA analysis revealed that 1,590 and 1,546 seed-stored mRNAs (long-lived mRNAs) were degraded in the white seeds of the top and the bottom layers, respectively, whereas those of the purple seeds in the top and bottom layers were 548 and 303, respectively. These results suggest that anthocyanin protected seeds and safeguarded long-lived mRNAs from solar light and space radiation to increase the seed viability.

"Monitoring inflammatory, immune system mediators, and mitochondrial changes related to brain metabolism during space flight".

The possibility of impaired cognitive function during deep space flight missions or while living on a Martian colony is a critical point of concern and pleads for further research. In addition, a fundamental gap exists both in our understanding and application of countermeasures for the consequences of long duration space travel and/or living in an extreme environment such as on the Moon or Mars. Previous studies, while heavily analyzing pre- and post-flight conditions, mostly fail to appreciate the cognitive stressors associated with space radiation, microgravity, confinement, hostile or closed environments, and the long distances from earth. A specific understanding of factors that affect cognition as well as structural and/or physiological changes in the brains of those on a space mission in addition to new countermeasures should result in improved health of our astronauts and reduce risks. At the core of cognitive changes are mechanisms we typically associate with aging, such as inflammatory responses, changes in brain metabolism, depression, and memory impairments. In fact, space flight appears to accelerate aging. In this review, we will discuss the importance of monitoring inflammatory and immune system mediators such as nuclear factor kappa B (NF-κB), and mitochondrial changes related to brain metabolism. We conclude with our recommended countermeasures that include pharmacological, metabolic, and nutritional considerations for the risks on cognition during space missions.

Numerical study on the thermal performance of space radiator using microencapsulated phase change material slurry as working medium

Microencapsulated phase change material slurry (MPCMS) has good prospects in the field of heat transfer because of its high latent heat and stability. In this research, MPCMS is applied to a space radiator to increase its heat load and temperature stability. The thermal performance of the space radiator is numerically studied by using the two-phase Eulerian (TPE) model and a multi-scale coupling model. The effects of velocity, volume fraction, microcapsule size, and microcapsule size distribution on the thermal performance of the space radiator are studied. Results show that the temperature flat area in the tube increases with the increase in the volume fraction or flow rate of the particle phase in the MPCMS, which means the heat dissipation capacity of the space radiator is also enhanced, and the maximum increase is 14 %. Compared with the use of pure water, the temperature difference between the highest and the lowest temperature of the radiator surface can be reduced by 40 %, and the heat dissipation power can be increased by 5 %. In addition, the large size of microcapsules limits the heat transfer between the two phases, especially when the size is greater than 50 μm. Compared with uniform microcapsule size distribution, the effect of lognormal distribution of variance σ = 0.7 on heat transfer is less than 1 %.

RadLab: An open science resource for radiation studies relevant to human spaceflight

In response to the growing need of the space life sciences community for a publicly available single access point for radiation physics data relevant to human space exploration, an open data repository and analysis platform, RadLab, has been developed. RadLab consists of a database and a user-friendly data retrieval, visualization, and analysis toolkit, including a graphical user interface (GUI) and an application programming interface (API). RadLab complements the space biology data in the NASA Open Science Data Repository (OSDR) and aims to provide open, centralized access to radiation physics data relevant to spaceflight. Analysis tools contained in RadLab will facilitate intercomparison among different detectors and radiation data sets to better understand the radiation environment in spacecraft and planetary habitats, and facilitate the use of space radiation data by space biology investigators and radiation instrument developers.

Upcoming MSU cubesats for space weather and astrophysical research

The program of space exploration using small spacecraft, implemented at Moscow State University, involves the installation of a set of instruments for detecting energetic particles and gamma rays on cubesat satellites. Currently, cubesats equipped with DeCoR scintillation spectrometers designed to study space weather factors and astrophysical phenomena are operating in orbit. The use of two-layer scintillation detectors makes it possible to register gamma quanta and electrons separately, which gives the possibility to study the dynamics of radiation belts and electron precipitation simultaneously with solar and astrophysical gamma ray bursts in an experiment in a solar-synchronous orbit. The results of ground-based calibrations, as well as monitoring measurements in orbit using DeCoR instruments on cubesats launched in June 2023, demonstrate good opportunities for conducting the above-mentioned studies. In order to further improve the ability to conduct detailed studies of space radiation, MSU plans to use detector suites composed of two units: a position-sensitive detector based on the set of GAGG:Ce crystals and one detector-spectrometer based on the CsI(Tl) crystal. Computer modeling shows the possibility of implementing such a suite on small satellites. In 2024, it is planned to launch two satellites with prototypes of an enhanced instrumental suite in order to test the methodology of detailed measurements.

Exploring Biomimetic Heat Pipes for Space Radiator Enhancement

This study investigates biomimetic heat pipes for space radiator applications, utilizing nature-inspired structures to potentially enhance heat transfer efficiency. The research addresses the imperative for improved heat dissipation mechanisms in nuclear space systems, crucial for effective thermal management. Heat pipes are passive heat transfer devices widely adopted for thermal control. The study aims to evaluate the effectiveness of a biomimetic heat pipe design in comparison to a traditional design while also validating the fabrication process through industry-made heat pipe comparisons. Innovative hot oil bath testing methods are employed to fabricate and test both heat pipe types, utilizing comprehensive thermal analysis, physical experiments, and validation techniques to assess heat transfer capabilities. Tests span varying temperature levels to analyze heat pipe behavior and performance. Findings suggest the potential for enhanced heat dissipation along the length of the biomimetic heat pipe, hinting at the biomimetic structure’s role in improving heat transfer. This study underscores the promise of biomimetic design principles and their potential for advancing heat pipe technology. Recommendations for further exploration include alternative materials, optimized testing procedures, and refined fabrication processes.

Galactic cosmic ray environment predictions for the NASA BioSentinel Mission, part 2:Post-mission validation

The BioSentinel CubeSat was deployed on the Artemis-I mission in November 2022 and has been continuously transmitting physical measurements of the space radiation environment since that time. Just before mission launch, we published computational model predictions of the galactic cosmic ray exposure expected inside BioSentinel for multiple locations and configurations. The predictions utilized models for the ambient galactic cosmic ray environment, radiation physics and transport, and BioSentinel geometry. Now that the nominal six-month BioSentinel mission has completed and some additional time has passed, those pre-launch predictions and additional model components can be validated. Dose-rate and linear energy transfer (LET) spectral measurements from the on-board dosimeter are presented along with a summary of the computational models used to calculate exposure quantities of interest. Sensitivity tests are performed to gauge the impact of various model choices on these quantities. Satellite data collected during the BioSentinel mission are used to provide some measure of independent validation for the galactic cosmic ray model used in the present calculations. It is shown that the combined models are in excellent agreement with the measured dose-rate. Model calculations agree well with measurement below ∼10 keV/µm and underpredict at higher LET. It is argued that the underprediction is likely due to detector response or low energy anomalous cosmic ray contributions able to reach the thinly shielded side of the on-board dosimeter.