Abstract The ability to detect and quantify specific nucleic acids is crucial for applications such as genetic research and real-time diagnostics. Polymerase chain reaction (PCR) and quantitative PCR (qPCR) are commonly used to detect DNA. However, these techniques are limited on-orbit due to the size and complexity of the equipment. To address these challenges, we have developed and characterized an alternative to qPCR, called fluoPCR, for use in spaceflight. The fluoPCR workflow consists of 1) a miniaturized thermal cycler to amplify target DNA sequences, 2) a handheld fluorescence viewer for optical detection of amplicons, and 3) data analysis to quantify fluorescence intensity. We tested the fluoPCR assay on the ISS across a range of target DNA sequence sizes and amounts. We found that targeted 100- and 400-base-pair (bp) sequences could be detected with high specificity and with quantifiable data patterns consistent with those obtained from ground qPCR assays. This investigation validates fluoPCR as a versatile alternative to qPCR for detecting and quantifying specific DNA sequences. It can be performed entirely aboard the ISS and similar space habitats and may enable quantitative nucleic acid detection for applications, from genetic research to molecular diagnostics, both in space and in resource-limited settings on Earth.
Abstract A successful popcorn experiment from a K-12 STEM engagement was flown to sub-orbital space and is described. To the authors’ knowledge, this is the first popcorn popped in spaceflight. The experiment topic provides numerous K-12 lessons in electrical and thermal energy and power, energy in compressed steam, the bursting of a pressure vessel, microprocessor control of hardware, and similar. Engineering challenges imposed by limited mass and power available to the K-12 payload are discussed, and the successful solution to the power limit problem is described. The experiment is the latest to fly in the Purdue School Launchbox on Blue Origin’s New Shepard vehicle. This experiment flew on Blue Origin’s NS-29 mission, which spun the Crew Capsule to create acceleration equal to lunar surface gravity, and so the popcorn kernel popped in space while subjected to lunar surface gravity.
Abstract Space-based plant pathology research must become common to support extraterrestrial crop production. Microbes, including phytopathogens, are inevitable in space-based bioregenerative life support systems. To support future space plant pathology research, we developed an inoculation system to apply fungal conidia (spores) of the powdery mildew phytopathogen, Golovinomyces cichoracearum (Gc) on to leaves of the host, Arabidopsis thaliana (At). Traditional ground-based inoculation protocols are not feasible in microgravity. Thus, the Conidia Application Device (CAD) was developed to aseptically transfer Gc conidia from a source container to plant canopies in custom-built petri dishes. The CAD system included a 3D-printed, cyclonic insert that interfaced with a vial of conidia and sealed completely within a 50-cc syringe. The syringe contained sterile air, which passed through the 3D-printed insert, aerosolized Gc conidia, and entered the dish through needleless Luer-lock connections. A secondary port on the Petri dish attached to a reservoir air bag to accommodate any excess volume of air injected into the dish. The ports on the Petri dishes were positioned to encourage airflow across the upper surfaces of plant canopies and promote inoculation. The CAD system was used to inoculate At canopies during ground-based pre-flight tests, resulting in successful Gc disease development.
Abstract Despite the decades that have passed since the last lunar landing, the elevated risk of developing cancer post-flight persists as a threat to astronaut health. High doses of ionizing radiation experienced during spaceflight exposure beyond low-Earth orbit (LEO) are a large contributing factor to cancer risk due to radiation-induced DNA damage. However, circadian rhythm disruption resulting from spaceflight-induced stress may serve to augment such radiation-induced harm. Upon re-analysis of “GLDS-248: The Transcriptional Analysis of Lung From Mice Flown on the RR-6 Mission” from the NASA GeneLab data repository, six circadian genes were differentially expressed as a result of spaceflight conditions. One such gene found to be up-regulated in relation to ground control was Arntl, which plays a crucial role in regulating cell cycle progression as a core clock gene. Others included Npas2 (up-regulated), which functions similarly to Arntl, and Per3 (down-regulated), which regulates Arntl activity. Due to these results, we hypothesize that circadian rhythm disruption during spaceflight heightens radiation-induced DNA damage due to impaired DNA repair pathways, thus inducing tumorigenesis. This paper seeks to elucidate how transcriptional regulation of the circadian clock influences cancer prognosis during spaceflight exposure, an increasingly relevant research area as NASA focuses beyond the LEO and exposure to galactic cosmic radiation becomes an increasingly significant concern to astronaut health.
Many new tools for morphological and developmental studies have become available to plant biology researchers, including software capable of collecting data, nearly automatically, from phenotypic assays. In this study, we compare the validity and accuracy of data on the growth of seedlings collected using ImageJ software with data collected using a more automated software, termed Simple Online Automated Plant Phenomics (SOAPP). Images from a Genome-Wide Association Study (GWAS) investigating the responses of twenty wild-type plants to gravity were analyzed using both methods and compared. Seedlings were grown in either static or stationary conditions or mounted on a rotating 2D clinostat. We found that although human error did create variability between repeated measurements using ImageJ, while SOAPP exhibited none, the validity of data collected using ImageJ was greater than that collected using SOAPP automation. The manual measurements with ImageJ revealed that one of the Arabidopsis thaliana wild-type lines, AP-Ara-4, experienced less stress due to altered gravitational conditions than the other nineteen lines analyzed. Updates and new features added to the SOAPP software will continue to improve the user interface and the quality of data collected, but it is already valuable as a tool capable of perfect replicability in its measurements of plant growth and development.
Functional water recovery systems will be a limiting factor for future spaceflight missions traveling beyond low Earth orbit. Previously, microbial communities known as biofilms have clogged valves in the International Space Station (ISS) water recovery system. To prevent part replacement, ensure safe water for astronauts, and enhance sustainability of long-term spaceflight, improved methods of biofilm control are needed. In this study, three approaches were evaluated for their ability to control biofilm alone and in combination. The methods include the use of Sher-Loxane® 800, a commercially available coating, exclusion of phosphorus from the growth medium, and regular dosing with a silver fluoride biocide. These strategies have all been proposed for biofilm control in spacecraft but have not been evaluated together. Further, this research uniquely features a defined multidomain consortium of organisms (a fungus and three bacteria) frequently isolated from the ISS water system. Results indicate that the presence of the coating is a key factor in reducing biofilm accumulation, and that combining all three biofilm control methods reduces accumulation of viable biofilm to just above the limit of detection after seven days of growth. This study presents the potential for controlling biofilm with multiple methods for spacecraft and Earth-based water systems.
Microgravity significantly impacts cellular functions and physiological systems, leading to oxidative stress and cellular dysfunction. This study investigated the effects of simulated microgravity on bioprinted vascular tissue constructs made with human skin fibroblast cells encapsulated in GelMA-based bioink. The bioprinting parameters were optimized to obtain tissue constructs with high structural integrity and cellular viability. Cellular viability remained high despite some cell death, likely caused by shear stress during bioprinting or limited nutrient availability while maintaining the samples in a bioreactor. The samples were stained with DHE solution to characterize the oxidative stress and imaged using a confocal microscope. The study revealed that oxidative stress, quantified by reactive oxygen species (ROS) levels, increased significantly after 48 h of simulated microgravity exposure. The ROS levels rose from 24 h to 48 h and then there was a subsequent decrease at 72 h, which reflects typical cellular responses to stress from microgravity such as cell adaptation and possible recovery mechanisms. These findings highlight the need for targeted strategies, such as incorporating antioxidants or mitochondria supporting compounds into the bioinks and dynamic culture systems to mitigate the effects of microgravity-induced oxidative stress.
The forthcoming human deep space exploration missions necessitate a thorough understanding of the impact of spaceflight conditions on human physiological systems. The NASA Open Science Data Repository (OSDR; https://osdr.nasa.gov/bio/ ) serves as a valuable resource, housing data derived from model organisms and human experiments conducted in spaceflight and terrestrial microgravity analogues. Machine Learning applications could maximize the use of existing data to understand and ultimately counteract physiological abnormalities during long-term missions. In our present study, we identified enriched terms and pathways associated with significantly dysregulated genes within each species and across orthologous counterparts. We also generated AI-ready merged meta-datasets comprised of musculoskeletal tissues from Mus musculus and Homo sapiens organisms. We then applied a series of supervised Machine Learning models to classify genes that were significantly over-expressed and under-expressed. Subsequently, we explored the utility of Transfer Learning in this domain by pretraining a model on the larger Mus musculus merged dataset and then refining it on the smaller Homo sapiens dataset. This approach showcases the potential of Transfer Learning in providing an insight into the effective transfer of information from model organisms to humans, offering a robust framework for advancing research in space biology and developing countermeasures for long-duration space exploration.
Plant production in microgravity is essential for sustaining astronauts long-term space missions. However, previous containerized plant cultivations in space has yielded inconsistent results, largely due to challenges in understanding the hydraulic properties of porous media, particularly water retention characteristics (WRCs) and hydraulic potential ( H ) under microgravity. This study addresses the issue of over-fertigation in the root zone, a persistent challenge in past space-based systems. We propose an on-demand passive fertigation system, regulated by a check valve-controlled H and tailored to the WRCs of the porous medium. Our system consists of 1) H regulation via a coupled check valve and porous membrane, 2) a water reservoir (collapsible for μg) and 3) containerized porous media. We determined target matric potential values for three particle size ranges of aggregated calcined clay to maintain adequate volumetric water content during 60 days of continuous romaine lettuce cultivation. This system supplies water only within a range of H , associated with the opening and closing of the check valve, requiring no automation or power. The findings could be adapted to reduced gravity (lunar or Martian) conditions. While this study establishes a foundation for on-demand fertigation, further research is needed to refine check valve characteristics for long-term cultivation.
Sustainable cultivation of nutrient-rich vegetables is crucial for long-term space missions. Leafy greens such as red romaine lettuce and hybrid leafy Asian green are promising candidates due to their compact growth and high nutritional value. However, these crops can accumulate excessive nitrate and iron (Fe), potentially posing health risks in space. Nitrate (NO 3 − ) may convert to carcinogenic nitrosamines when consumed with processed foods under acidic gastric conditions, while excess Fe contributes to oxidative stress and bone loss. Ideal crop characteristics prioritize high potassium, magnesium, and calcium (Ca) concentrations while minimizing Fe accumulation to support astronaut cardiovascular and skeletal health. This study hypothesizes that elevated light intensity and CO 2 enrichment could reduce NO 3 − accumulation while preserving favorable nutrient profiles. Using NASA's Growing Beyond Earth (GBE) 2023 research protocol, seeds were first exposed to neutron radiation via Californium-252 and then cultivated under controlled LED lighting and elevated CO 2 conditions to simulate spaceflight growing environments. Neutron radiation had no statistically significant effect on edible biomass or morphology ( p > 0.05). CO 2 enrichment significantly reduced NO 3 − content, partially supporting the hypothesis, but led to nutrient trade-offs, including increased Fe levels and reduced magnesium and Ca. Contrary to expectations, higher light intensity increased nitrate accumulation. A NASA-aligned crop suitability ranking identified low light intensity (230 μmol·m −2 ·s −1 PPFD) and CO 2 enrichment (~1000 ppm) as the optimal conditions for enhancing space crop quality while mitigating dietary risks. These findings may inform NASA's space agriculture strategies for sustainable food production on long-duration missions and offer insights for controlled environment agriculture in resource-limited settings on Earth.
Understanding the effects of space radiation and microgravity on DNA is critical to assessing the impact of long-term spaceflight. While experiments performed in space constitute the most effective means of examining these effects, opportunities are limited and costly. As this bottleneck will likely continue for the foreseeable future, data from past experiments represent a particularly valuable source of information for continuing studies. To this end, NASA created GeneLab, a public Omics database for spaceflight-related data. We used data from GeneLab to examine the effect of spaceflight on DNA mutation rates. Optimally, mutation rates are estimated using DNA sequence data directly. Unfortunately, to date, few DNA-based datasets appear in GeneLab. Transcript data, however, is abundant. Here we used RNA-Seq data to examine DNA sequence variation in Arabidopsis thaliana seedlings grown aboard the International Space Station (ISS) vs. on the ground. ISS-based samples were grown under two conditions: spaceflight under microgravity, and, by using a specialized onboard centrifuge under induced gravity. This powerful experimental design allowed us to separate the effects of microgravity from non-microgravity spaceflight stress, such as space radiation. More mutations were observed in spaceflight samples than in ground control samples, with transversion mutations being overly represented. Mutation rates identified in samples grown under artificial gravity in space were similar to that of microgravity spaceflight samples, indicating that microgravity exposure played a limited role. This work demonstrates that RNA-Seq data is useful for evaluating DNA damage from spaceflight and provides insight into the types of mutations that occur.
In-situ food production for long-duration space missions is currently reliant on crop production, with plants grown from seed serving as a potential source of nutrient supplementation to astronaut diets. Microgravity presents significant challenges to seed handling, growth system integration, and storage. A primary concern is the generation of environmental debris and particulates. This will require extended-duration spaceflight missions to incorporate innovative and reliable methods to handle and prepare seeds for cultivation. This study investigates the potential of Japanese oblate film, a thin, starch-based, edible film traditionally used to wrap ill-tasting powdered medicines, as a method for seed handling in space environments. These films feature a thin, flexible structure that facilitates efficient handling and a water-soluble composition, allowing for integration into cultivation systems. Japanese cherry red radish seeds were adhered to oblate sheets, immobilizing them to prevent debris formation during handling and ensure consistent positioning for growth. The sheets were placed on non-enriched agar media plates, activating the seeds and simulating passive hydroponic systems that could be utilized during future space missions. Results indicate that seeds prepared with oblate film exhibited significantly faster germination rates within the first 24 hours and higher overall germination rates over a seven-day period compared to control groups. This study demonstrates the potential of Japanese oblate film as an effective solution for seed handling and activation in microgravity environments, with possible applications for storage in long duration space agriculture operations.
Space-based research can provide fundamental insight into assembly processes that are of central importance in physics, material science and biology. Colloidal particles have served as a model system to study the assembly at convenient time and length scales, and microgravity research has played an important role in studying these assembly processes in their purest form without disturbance by sedimentation. Recently, anisotropic particles have emerged, opening the door to the study of complex structures; specifically, patchy particles enabling directed bonding promise the assembly of structures that could mimic those of molecular compounds. Based on previous space research on tunable attractive particles, here we explore the use of patchy colloidal particles for studying the assembly of complex structures in space. The particles interact along their patches via temperature-tunable critical Casimir interactions with bond energies of several (ten) k B T, the thermal energy. The tunability and reversibility of these critical Casimir forces allows convenient remote control of the colloidal interactions from the ground, enabling the repeated formation and break-up of the structures without much intervention by the astronaut. Together with the confocal microscope extension of the Light Microscopy Module on board the International Space Station, this offers unique opportunities for investigating complex structure formation in real space without disturbance by gravity.
Abstract Fungi are natural decomposers that degrade organic substrates for growth. On Earth, fungi grow and produce mushrooms on various natural substrates, often with little to no added nutrient supplements. Existing waste substrates found on board the International Space Station (ISS) such as inedible biomass from plants, clothing, and plastic wastes from prepackaged foods could be repurposed for food production and advance the capacity for more sustainable long-duration space missions. The sporeless oyster mushroom (Pleurotus ostreatus) strain SPX was grown on seven substrates in varied combination recipes to investigate how ISS waste streams could be used to cultivate mushrooms. In addition, food safety analyses were performed to assess the feasibility of mushroom cultivation as a low-risk food option. Results show that waste streams of cotton t-shirts and inedible biomass from plants are potential substrates that could support mushroom cultivation on board the ISS. By using materials that are already available on the station, the upmass needed to support such efforts is reduced and waste products can be recycled to potentially yield more food. This investigation was intended to identify the feasibility of incorporating mushrooms as a potential space crop without the requirement of a large upmass of substrates being brought to the ISS.
Abstract As human settlements expand to lunar and Martian bases, optimizing food production in these environments becomes crucial. This study investigates the use of macroalgae, specifically Ulva lactuca L., as an affordable, sustainable approach for seed priming to enhance germination in extraterrestrial soils. The focus was on the germination and growth of Capsicum annuum L. (pepper), Lactuca sativa L. (lettuce), Cicer arietinum L. (chickpea), and Pisum sativum L. (pea) in simulated Martian and lunar regolith. Two concentrations of U. lactuca powder (0.2 and 0.4 g · L−1) were tested under controlled conditions. The study also conducted a qualitative chemical analysis of U. lactuca to identify bioactive components essential for phytohormone formation. The germination and emergence rates of the seeds in the lunar regolith were higher than those in the Martian regolith. Martian regolith's optimal treatment for pea and chickpea seed germination was 0.2 g · L−1, which also favored seedling emergence. In the lunar regolith, optimal germination rates for pea seeds were observed with both treatments and chickpea seeds. The germination percentage of lettuce seeds in the lunar regolith was higher than the control, with 0.2 g · L−1, while there was no significant difference for the other seeds. The study recommends the application of U. lactuca powder as an effective biostimulant for the examined cultivars due to the presence of plant growth regulators (PGRs) that enhance germination and seedling emergence under challenging conditions.
Abstract Plants experience the constant pull of gravity on Earth, affecting their growth and development. Recent research has focused on how plants respond to hypergravity, a greater gravitational force compared to 1g. In this study, we examined whether hypergravity could generate new phenotypic traits in sorghum plants. Imbibed sorghum seeds were exposed to varying levels of hypergravity using a centrifuge for short durations, with a 1000g for 1 hour (1000 times Earth's gravity for 1 hour) resulting in enhanced seedling growth and overall plant vigor, both in controlled laboratory settings and greenhouse conditions. Following the screening of several sorghum genotypes, three showed the most promising responses to hypergravity and were further studied. We also investigated the biochemical and hormonal changes triggered by hypergravity. Our findings demonstrated increased enzyme activity in seeds and seedlings, along with elevated chlorophyll levels critical for photosynthesis. Additionally, alterations in the levels of specific plant hormones in the roots, notably 3-indole Acetic Acid and indole-3-butyric acid, appeared to influence root growth. These findings suggest that hypergravity holds the potential for developing novel plant traits with implications for future agricultural advancements.
Abstract There is a broad interest in both industry and academe in understanding the time-evolution in the microstructure of colloidal gels, as such changes affect the properties of the gels including product self-life and rheology. In colloidal gels, the time-evolution results from the magnitude and the relative proportions of forces—including gravity, acting on the colloidal particles. The aim of this study was to measure the magnitude of the Soret force acting on the colloidal particles in a model gel in the microgravity on the International Space Station, as a proxy for gravitational forces in Earth-based experiments. It was found that the Soret force could be used to create an effective gravitational force of between about 10 × 10−17 N (3 milli-G) and 3 × 10−17 N (1 milli-G) on the colloidal particles, where the lower limit is set by the dominance of particle flux from Brownian forces. These results should allow mapping the behavior of colloidal gels broadly described in literature on other gels—such as polymer gels of industrial interest, where the colloidal particles are much smaller.
Abstract The International Space Station (ISS) National Laboratory provides an ideal platform in persistent microgravity to conduct research in the absence of gravity-induced phenomena (e.g., buoyancy-driven convection and sedimentation), enabling opportunities for breakthrough science. Since 2016, the U.S. National Science Foundation (NSF) Chemical, Bioengineering, Environmental, and Transport Systems (CBET) Division has partnered with the Center for the Advancement of Science in Space™ (CASIS™), manager of the ISS National Lab, to release an annual joint solicitation in transport phenomena research on the ISS to benefit life on Earth. To date, the NSF-CASIS partnership has yielded 37 NSF-funded research investigations sponsored by the ISS National Lab. This paper highlights a few of the important scientific discoveries that have resulted from the fruitful NSF-CASIS collaboration and offers insight into the importance of expanding collaborations between government agencies to increase access to space and enable groundbreaking research that benefits humanity. Research areas explored include biophysics, combustion, complex fluids, fluid dynamics, heat transfer and multiphase flow, and materials science.
Successful sub-orbital flight operations of a novel method for autonomously controlling GoPro cameras in microgravity, without any additional mechanical device, are described. The method employs the use of GoPro Labs software to control the power and recording functions of a camera via its USB port and integrates the camera and control with the Integrated Payload Controller (IPC) of the Blue Origin New Shepard crew capsule or with microprocessor control of cameras in Virgin Galactic’s VSS Unity. Control of four GoPro Hero-10 cameras on a single power port on the IPC is achieved. The method operated successfully on the Blue Origin New Shepard NS-24 suborbital flight, recording data in the experiment and demonstrating reliable start- and stop-recording functions during the flight. The authors also operated four GoPro Hero-11 cameras via USB port recording control on Virgin Galactic’s June 8, 2024 flight. Hardware specifications for the experimental setup and the ability to operate after extended periods of inactivity are discussed.
Abstract The self-assembly of colloidal particles enables the creation of complex materials with tailored properties. This process, particularly involving anisotropic particles, can lead to the formation of structurally unique and complex assemblies that are not achievable with isotropic particles. On Earth, gravitational forces limit the investigation of these particles’ intrinsic motion and interactions, posing significant challenges to comprehensively understanding the fundamental forces governing their interactions. To overcome these limitations, this study, in collaboration with NASA’s Glenn Research Center (GRC), employs the Light Microscopy Module (LMM) aboard the International Space Station (ISS) to observe the self-assembly phenomena of anisotropic particles under microgravity conditions. Our investigation shows that anisotropic Janus particles with their distinctive properties can spontaneously organize into ordered structures under microgravity. This directional interaction among anisotropic particles is expected to enable control over assembly processes, forming three-dimensional (3D) clustered structures that are unattainable on Earth. Thus, this study not only advances our understanding of particle self-assembly in microgravity but also opens new avenues for synthesizing materials with novel functionalities through the unique assembly of anisotropic colloids.
