ISS Astronauts Eat the First Lettuce Grown in Space

One small stem for man, one giant leaf for mankind.

Astronauts of Expedition 44 aboard the International Space Station became the first to eat produce grown in the microgravity environment of space on Monday 10th August. The crop of red romaine lettuce, previously tested for microbiological safety, was cleaned using citric acid sanitising wipes before consumption. Half the harvest is also returning to Earth for scientific analysis, as part of NASA’s plant experiment Veg-01.

The lettuce was grown over 33 days using the ‘Veggie’ vegetable production system developed by ORBITEC. The process involves seed pillows being installed on a root mat in the Veggie bellows, through which power and nutrient rich water begin germination. Although Veggie provides light and nutrient delivery, it uses the cabin environment as a source of carbon dioxide and temperature control.

According to Dr. Ray Wheeler, lead for Advanced Life Support activities at Kennedy, the idea of using LED lights to grow plants can be traced to the late 1990s in NASA. He explained, “Blue and red wavelengths are the minimum needed to get good plant growth and are probably the most efficient in terms of electrical power conversion.” However, green LEDs are also used by Veggie so that the plants have a more appetising colour, although a purple hue results from greater emission of red and blue light.

The Veggie technology may enable future long-duration space missions, such as NASA’s aim to send humans to Mars in the 2030s. NASA payload scientist Giola Massa explains, “The farther and longer humans go… the greater the need to be able to grow plants for food, atmosphere recycling and psychological benefits.” Wheeler also suggests, “Having fresh food like these available in space could have a positive impact on people’s moods,” reminding them of Earth and providing recreational gardening.