Tomatoes grown on the International Space Station (ISS) will return to Earth tomorrow from a successful Nasa study into fresh food supply for future astronauts.
Samples from Nasa studies into plant growth are returning from the ISS on April 15 aboard a SpaceX commercial resupply services mission for the agency.
After splashdown, the scientific samples will be taken to Nasa’s Kennedy Space Center in Florida where scientists will perform additional analyses before the effects of gravity fully kick in.
Future crewed exploration missions, such as missions to Mars, may require a fresh food supply to supplement the pre-packaged crew meals.
The Veg-05 experiment grew dwarf tomatoes in the station’s Veggie facility to examine the effects of light quality and fertilizer on fruit production, microbial safety, and nutritional value.
The Veggie vegetable-production system on the ISS offers an opportunity to develop a ‘pick-and-eat’ fresh vegetable component to food on the space station.
This particular investigation is expected to help define horticultural best practices to achieve high yields of safe, nutritious dwarf tomato fruit to supplement a space diet of pre-packaged food.
It was also used to assess any psychological impacts that growing plants might have on the astronauts.
For this study, salad plants like leafy greens and dwarf tomatoes were grown in the Veggie units during spaceflight, focusing on the impact of light quality and fertilizer formulation on the crops.
A duplicate ground-study provided a comparison to the plants grown on the ISS to determine the effects of spaceflight.
Each crop was grown in two separate Veggie chambers under two different LED lighting conditions. Six plants were grown using plant ‘pillows’, which are bags with a wicking surface containing soilless substrate and fertilizer.
The plants were grown for 104 days where crew members tended to them by opening wicks to help seedlings emerge, providing water, thinning the seedlings, pollination, and monitoring health and progress
Crew members also took several questionnaires to survey their mood in response to plant growth.
Crew members, after eating the tomato fruit, are asked to rate the flavour, texture, juiciness, etc. of the produce grown under the different light treatments.
The crew performed three harvests at 90, 97, and 104 days, freezing the tomatoes along with water samples and swabs of the growth hardware. Those are the samples that are returning to Earth for analysis.
Why grow plants in space?
The capability to grow plants in space for fresh food and to enhance the overall living experience for crew members is key to future long-duration missions.
Plants in space have potential countermeasure benefits. Fresh vegetables offer flavour, sensory, and texture variety to the pre-packaged ISS diet.
Taking care of the plants also provides astronauts with sensory stimulation and helps mark the passage of time in the confined and isolated environment of the ISS.
The miniature greenhouse used to grow these plants could also be adapted to provide fresh produce for those without access to a yard on Earth and for horticultural therapy for elderly or disabled individuals.
Studies of edible produce during spaceflight have been limited, leaving a significant knowledge gap in the methods required to grow safe, acceptable, nutritious crops for consumption in microgravity.
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