The ability to grow safe, fresh food to supplement packaged foods of astronauts in space has been an important goal for NASA. Food crops grown in space experience different environmental conditions than plants grown on Earth (e.g., reduced gravity, elevated radiation levels). To study the effects of space conditions, red romaine lettuce, Lactuca sativa cv ‘Outredgeous,’ plants were grown in Veggie plant growth chambers on the International Space Station (ISS) and compared with ground-grown plants. Multiple plantings were grown on ISS and harvested using either a single, final harvest, or sequential harvests in which several mature leaves were removed from the plants at weekly intervals. Ground controls were grown simultaneously with a 24–72 h delay using ISS environmental data. Food safety of the plants was determined by heterotrophic plate counts for bacteria and fungi, as well as isolate identification using samples taken from the leaves and roots. Molecular characterization was conducted using Next Generation Sequencing (NGS) to provide taxonomic composition and phylogenetic structure of the community. Leaves were also analyzed for elemental composition, as well as levels of phenolics, anthocyanins, and Oxygen Radical Absorbance Capacity (ORAC). Comparison of flight and ground tissues showed some differences in total counts for bacteria and yeast/molds (2.14 – 4.86 log10 CFU/g), while screening for select human pathogens yielded negative results. Bacterial and fungal isolate identification and community characterization indicated variation in the diversity of genera between leaf and root tissue with diversity being higher in root tissue, and included differences in the dominant genera. The only difference between ground and flight experiments was seen in the third experiment, VEG-03A, with significant differences in the genera from leaf tissue. Flight and ground tissue showed differences in Fe, K, Na, P, S, and Zn content and total phenolic levels, but no differences in anthocyanin and ORAC levels. This study indicated that leafy vegetable crops can produce safe, edible, fresh food to supplement to the astronauts’ diet, and provide baseline data for continual operation of the Veggie plant growth units on ISS.

The ability to grow safe, fresh food to supplement packaged foods of astronauts in space has been an important goal for NASA. Food crops grown in space experience different environmental conditions than plants grown on Earth (e.g., reduced gravity, elevated radiation levels). To study the effects of space conditions, red romaine lettuce, Lactuca sativa cv ‘Outredgeous,’ plants were grown in Veggie plant growth chambers on the International Space Station (ISS) and compared with ground-grown plants. Multiple plantings were grown on ISS and harvested using either a single, final harvest, or sequential harvests in which several mature leaves were removed from the plants at weekly intervals. Ground controls were grown simultaneously with a 24–72 h delay using ISS environmental data. Food safety of the plants was determined by heterotrophic plate counts for bacteria and fungi, as well as isolate identification using samples taken from the leaves and roots. Molecular characterization was conducted using Next Generation Sequencing (NGS) to provide taxonomic composition and phylogenetic structure of the community. Leaves were also analyzed for elemental composition, as well as levels of phenolics, anthocyanins, and Oxygen Radical Absorbance Capacity (ORAC). Comparison of flight and ground tissues showed some differences in total counts for bacteria and yeast/molds (2.14 – 4.86 log10 CFU/g), while screening for select human pathogens yielded negative results. Bacterial and fungal isolate identification and community characterization indicated variation in the diversity of genera between leaf and root tissue with diversity being higher in root tissue, and included differences in the dominant genera. The only difference between ground and flight experiments was seen in the third experiment, VEG-03A, with significant differences in the genera from leaf tissue. Flight and ground tissue showed differences in Fe, K, Na, P, S, and Zn content and total phenolic levels, but no differences in anthocyanin and ORAC levels. This study indicated that leafy vegetable crops can produce safe, edible, fresh food to supplement to the astronauts’ diet, and provide baseline data for continual operation of the Veggie plant growth units on ISS.

Human expansion into the solar system is currently at the forefront of space research. For our astronauts to survive, they will need to be fed a healthy and nutritious diet on a consistent basis. Right now, our current method of feeding astronauts consists of resupplied prepackaged food from Earth, which is unsustainable for long-term missions. Using planetary resources via in situ resource utilization to grow crops is the next step toward sustainability in space. Asteroids are an abundant space resource and should not be overlooked when considering crewed missions. In particular, the primordial CI carbonaceous asteroids are of interest because the regolith is suggested to contain soluble elemental nutrients, such as phosphorous and potassium, that crops can use for growth and development. We present a study on the ability of CI carbonaceous asteroid regolith simulant to sustain plant growth of lettuce (Latuca sativa), radishes (Raphanus sativus), and peppers (Capsicum annuum). We tested growing the selected crops in increasing mixtures of simulant and peat moss. The results showed that each species reacted differently to each treatment and that the radishes were more affected by the treatments. Subsequent analysis showed that the simulant contains small amounts of plant-usable nutrients, despite its high pH, low cation exchange capacity, and classification as a silt-based soil. Our results indicate that the simulant is prone to compaction and crusting, leading to drought stress on the crops. Further investigations are needed to determine mitigation strategies to make CI asteroid regolith a more conducive soil. This data set derives results from the Image Analysis Photography assay with leaf area measurements. Additional data provided in the sample table includes plant height and biomass measurements as well as a thorough analysis of the substrate including pH, elemental analysis, and soil texture analysis.

Understanding the molecular mechanisms by which plants sense and adapt to changes in the space environment is essential for generating plants that are better adapted to withstand space flight, microgravity, and other adverse conditions encountered in space. The objective of our spaceflight experiment “Plant Signaling in Microgravity” (carried out on the International Space Station, ISS), was to compare transcript profiles of wild type and transgenic InsP 5-ptase plants with compromised InsP3 signaling. The transgenic Arabidopsis plants constitutively express the mammalian type I inositol polyphosphate 5-phosphatase (InsP 5-ptase), an enzyme that specifically hydrolyzes the lipid-derived second messenger inositol 1,4,5-trisphosphate (InsP3). These transgenic plants exhibit normal growth and morphology; however, their responses to environmental stimuli including gravity and drought are altered. Seedlings were grown for 5 days under continuous light in experimental containers placed in the European Modular Cultivation system (EMCS) onboard the ISS. The EMCS consists of two rotors within a controlled chamber, allowing for a “1g” control in space. After sample retrieval from the ISS, RNA was isolated from shoot and root tissue and subjected to RNA sequencing. Two-way comparisons of micro g versus “1”g have uncovered regulatory mechanisms that are both conserved and altered between the wild type and transgenic seedlings.

This study's objective was to develop an understanding of the biological effects of space radiation on plants with the goal of producing fresh food during long duration space missions to support astronauts' nutritional and psychological needs.10-day-old Arabidopsis seedlings were exposed to simulated Galactic Cosmic Rays (GCR) and assessed for transcriptomic changes. The simulated GCR irradiation was carried out in the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Lab (BNL). The exposures were conducted acutely for two dose points at 40 cGy or 80 cGy, with sequential delivery of proton, helium, oxygen, silicon, and iron ions. Control and irradiated seedlings were then harvested and stabilized in RNAlater at 3 hrs. post irradiation. Total RNA was isolated for transcriptomic analyses using RNAseq. The data revealed that the transcriptomic responses were dose-dependent, with significant upregulation of DNA repair pathways and downregulation of glucosinolate biosynthetic pathways. Glucosinolates are important for plant pathogen defense and for the taste of a plant, which are both relevant to growing plants for spaceflight. These findings fill in knowledge gaps of how plants respond to radiation in beyond-Earth environments.

The project focuses on understanding the transcriptional and post-transcriptional mechanisms that regulate early seedling development in spaceflight and microgravity. One of the goals of the PRR experiment was to study the role of small regulatory RNAs in plant response to the space environment using Arabidopsis thaliana.

Understanding the molecular mechanisms by which plants sense and adapt to changes in the space environment is essential for generating plants that are better adapted to withstand space flight microgravity and other adverse conditions encountered in space. The objective of our spaceflight experiment x93Plant Signaling in Microgravity x94 (carried out on the International Space Station ISS) was to compare transcript profiles of wild type and transgenic InsP 5-ptase plants with compromised InsP3 signaling. The transgenic Arabidopsis plants constitutively express the mammalian type I inositol polyphosphate 5-phosphatase (InsP 5-ptase) an enzyme that specifically hydrolyzes the lipid-derived second messenger inositol 1,4,5-trisphosphate (InsP3). These transgenic plants exhibit normal growth and morphology; however their responses to environmental stimuli including gravity and drought are altered. Seedlings were grown for 5 days under continuous light in experimental containers placed in the European Modular Cultivation system (EMCS) onboard the ISS. The EMCS consists of two rotors within a controlled chamber allowing for a x931g x94 control in space. After sample retrieval from the ISS RNA was isolated from shoot and root tissue and subjected to RNA sequencing. Two-way comparisons of micro g versus x931 x94g have uncovered regulatory mechanisms that are both conserved and altered between the wild type and transgenic seedlings.

The Cosmic Ray Exposure Sequencing Science (CRESS) payload system is a proof of concept experiment to assess the genomic impact of space radiation on seeds. CRESS was designed as a secondary payload for the December 2016 high-altitude high-latitude and long-duration balloon flight carrying the Boron And Carbon Cosmic Rays in the Upper Stratosphere (BACCUS) experimental hardware. Investigation of the biological effects of Galactic Cosmic Radiation (GCR) particularly those of ions with High-Z and Energy (HZE) is of interest due to the genomic damage this type of radiation inflicts. The biological effects of upper-stratospheric mixed radiation above Antarctica (ANT) were sampled using Arabidopsis thaliana seeds and were compared to those resulting from a controlled simulation of GCR at Brookhaven National Laboratory (BNL) and to laboratory control seed. The payload developed for Antarctica exposure was broadly designed to 1U CubeSat specifications (10cmx10cmx10cm <1.33kg) maintained 1 atm internal pressure and carried an internal cargo of four seed trays (about 580,000 seeds) and twelve CR-39 Solid-State Nuclear Track Detectors (SSNTDs). The irradiated seeds were recovered sterilized and grown on Petri plates for phenotypic screening. BNL and ANT M0 seeds showed significantly reduced germination rates and elevated somatic mutation rates when compared to non-irradiated controls with the BNL mutation rate also being significantly higher than that of ANT. Genomic DNA from mutants of interest was evaluated with whole-genome sequencing using PacBio SMRT technology. Sequence data revealed the presence of an array of genome structural variants in the genomes of M0 and M1 mutant plants.

Experimentation on the International Space Station has reached the stage where repeated and nuanced transcriptome studies are beginning to illuminate the structural and metabolic differences between plants grown in space compared to plants on the Earth. Genes that are important in establishing the spaceflight responses are being identified, their roles in spaceflight physiological adaptation are increasingly understood, and the fact that different genotypes adapt differently is recognized. However, the basic question of whether these spaceflight responses are actually required for survival has yet to be posed, and the fundamental notion that spaceflight responses may be non-adaptive has yet to be explored. Therefore the experiments presented here were designed to ask if portions of the plant spaceflight response can be genetically removed without causing loss of spaceflight survival and without causing increased stress responses. The CARA experiment compared the spaceflight transcriptome responses in the root tips of two Arabidopsis ecotypes, Col-0 and WS, as well as that of a PhyD mutant of Col-0. When grown with the ambient light of the ISS, phyD plants displayed a significantly reduced spaceflight transcriptome response compared to Col-0, suggesting that altering the activity of a single gene can actually improve spaceflight adaptation by reducing the transcriptome cost of physiological adaptation. The WS genotype showed an even simpler spaceflight transcriptome response in the ambient light of the ISS, more broadly indicating that the plant genotype can be manipulated to reduce the cost of spaceflight adaptation, as measured by transcriptional response. These differential genotypic responses suggest that genetic manipulation could further reduce, or perhaps eliminate the metabolic cost of spaceflight adaptation. When plants were germinated and then left in the dark on the ISS, the WS genotype actually mounted a larger transcriptome response than Col-0, suggesting that the in-space light environment affects physiological adaptation, which implies that manipulating the local habitat can also substantially impact the metabolic cost of spaceflight adaptation.

Arabidopsis thaliana was evaluated for its response to the spaceflight environment in three replicated experiments on the International Space Station. Two approaches were used; GFP reporter genes were used to collect gene expression data in real time within unique GFP imaging hardware, and plants were harvested on orbit to RNAlater for subsequent analyses of gene expression with using Affymetrix and SAGE transcriptome analyses. Three tissue types were examined (leaves, hypocotyls and roots) and compared to analyses conducted with whole plants. Transcriptome analyses with whole plants suggested that the spaceflight environment had little impact on the transcriptome of Arabidopsis, however, closer examination of selected tissues revealed that there are a number of tissue-specific responses that Arabidopsis employs to respond to this novel environment.