The first microbial assessment of produce cultivated in a soil-free setup on the International Space Station has been released by the Nasa Kennedy Space Centre alongside collaborators Sierra Space, Noetic Strategies, Amentum, and Bennett Aerospace.
The study, titled ‘Microbial community characterisation of multi-crop growouts in the XROOTS aeroponic-hydroponic system on the International Space Station‘ and led by Christina L. M. Khodadad and colleagues, examined lettuce, mizuna mustard, wheat, radish, tomato, and pea plants. Testing determined that the evaluated crop samples were entirely free of human pathogens such as Staphylococcus aureus, E. coli, and Salmonella.
Analysis of the XROOTS System on the ISS
The plants were grown in the eXposed Root On-Orbit Test System (XROOTS), an aeroponic-hydroponic nutrient delivery system developed by Sierra Space. Investigators created this hardware to evaluate the viability of cultivating crops without soil or traditional solid substrates, an approach capable of lowering payload weight requirements for extended crewed missions to Mars and the Moon.
Following its deployment to the ISS in February 2022, the hardware applied a mix of nutrient-solution flow and aerosol misting to supply moisture straight to the plant roots over the course of four separate cultivation cycles taking place between June and October 2022.
Crop Harvests Across Growouts
Researchers harvested mature tissue from multiple crops during the various growouts conducted on the space station:
- Mizuna mustard, radish, and lettuce were harvested in growout two.
- Wheat and lettuce were harvested in growout three.
- Pea and tomato plants were grown through to fruiting by growout four.
The findings from these space-grown crops provide new insights into microbial communities within substrate-free systems in microgravity environments.
