Abstract
One of NASA’s goals is growing edible crops in spaceflight to supplement the astronauts’ diet with fresh, safe-to-eat vegetables. Growing plants in spaceflight presents challenges to achieve optimal plant growth and productivity. It is important to understand the optimal conditions for crops grown in spaceflight. The Advanced Plant Habitat (APH), an enclosed, environmentally controlled plant growth facility on the International Space Station (ISS) has been used to grow plants and monitors the environment. A technology demonstration mission on the ISS used the APH to grow chile peppers, Capsicum annuum, cv. NuMex Española Improved to maturity. Over 25 peppers were successfully harvested as a mix of red and green peppers at 109 and 137 days after initiation. Half of the fruit were consumed by the crew, and half were frozen at − 80 °C and returned with the science carrier (SC) to Kennedy Space Center, FL to determine microbial load and food safety. Bacterial and fungal counts, ranged from below detection limit to 111 CFU/gram fresh weight found on a single pepper only. Foodborne pathogens were not detected. Investigation of the communities using the V4 region of the 16S rRNA gene revealed taxonomic variations between the SC quadrants as well as between hardware components and plant tissues, indicating possible vertical or horizontal transfer of some bacteria. An investigation into the bacterial communities indicated 13 genera and 1 unidentified microbe as possible core microbiome components. In addition, bacteria such as Burkholderia and Sphingomonas previously identified from ISS water samples were present in the communities. This technology demonstration growing a long duration fruiting crop on the ISS provided verification of the pre-determined environmental conditions, contributed to the validation of the APHs’ capability to support fruiting crops in space, and provided the crew a safe-to-eat addition to their pre-packaged diet. This technology demonstration may serve as a baseline for future space crop production systems or long duration spaceflight missions.
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Data availability
The datasets generated and analyzed during this study have been deposited and are available in the NASA GeneLab repository [https://osdr.nasa.gov/bio/repo/data/studies/OSD-772], **DOI**: [https://doi.org/10.26030/mjvk-v435]. This data set can be identified as OSD-772. The direct link is https://doi.org/10.26030/mjvk-v435. An alternative method for data access is to contact the corresponding authors, Drs. Anirudha Dixit or Christina LM Khodadad@nasa.gov.
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Acknowledgements
The authors would like to thank the Redwire Space staff for their science operations at Kennedy Space Center, the Sierra Space staff for facility operations and NASA astronauts Megan McArthur, Mark Van de Hei, Shane Kimbrough, Kayla Barron, and ESA astronaut Thomas Pesquet for nurturing the pepper plants during the growth period. The authors are grateful for the fertilizer counsel and support of Ed Rosenthal and Florikan ESA.
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Funding was provided by NASA’s Biological and Physical Sciences which funded the ground and development work. The International Space Station Program funded PH-04 flight study.
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CLK- experimental design, sample processing, data collection, data analysis, manuscript development; ARD- experimental design, sample processing, data collection, data analysis; manuscript development; MEH- experimental design, sample processing, data collection, data analysis; LES- experimental design, horticulture and crop management, project development; CJS- sample processing, data collection, manuscript development; JJT-project development, data collection, horticulture and crop management; OM- data collection, experimental design, project development; JTR-project management, project development, data collection, experimental design; JLG- sample processing, data collection; ABC- sample processing, data collection; GDM- project development, data collection, experimental design; ND- project management, project development; LP-experimental design, horticulture and crop management, data collection; MWR- project development, project management, experimental design, funding support; RMW- project development, experimental design, funding support. All authors read and approved the final manuscript.
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Khodadad, C.L.M., Dixit, A.R., Hummerick, M.E. et al. Evaluating microbial community profiles of Chile peppers grown on the International Space Station provides implications for fruiting crops. Sci Rep (2026). https://doi.org/10.1038/s41598-025-20440-9
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DOI: https://doi.org/10.1038/s41598-025-20440-9


