According to a study, published in the journal Frontiers in Plant Science, researchers have found that the salad crop, red romaine lettuce, grown on board the International Space Station (ISS), is as nutritious as counterparts grown on the Earth.
The space-grown lettuce is free of disease-causing microbes and safe to eat, and is at least as nutritious as the Earth-grown plants. The lettuce is nutritious despite being grown under lower gravity and more intense radiation than on the Earth, said the study.
Traditionally, astronauts in space live on processed, pre-packaged space rations such as fruits, nuts, chocolate, shrimp cocktails, peanut butter, chicken, and beef to name a few. The fresh produce may provide astronauts with additional potassium as well as vitamins K, B1, and C — nutrients that are less abundant in pre-packaged rations, and degrade during long-term storage.
Growing crops on board may be especially useful on long-distance space missions such as the upcoming Artemis-III missions, scheduled to land humans on the lunar South pole by 2024, and NASA’s first crewed mission to Mars, planned for the late 2020s.
The study noted that between 2014 and 2016, lettuce was grown on board the ISS from surface-sterilised seeds within Vegetable Production Systems, nicknamed “Veggie” — growth chambers equipped with LED lighting and a watering system, specifically designed to grow crops in space.
It said the crops grew undisturbed inside the Veggie units for 33 to 56 days, until crew members ate part of the mature leaves without any negative health effects. The scientists said the remainder of the crops was deep-frozen until transport back to the Earth for chemical and biological analysis.
The study noted that in some trials, the space-grown plants tended to be richer in elements like potassium, sodium, phosphorus, sulphur, and zinc, as well as in some molecules with proven antiviral, anticancer, and anti-inflammatory activity.