Third Lettuce Crop Begins Growing Aboard International Space Station

Veggie team members in monitor Veg-03 activation aboard the International Space Station via a live video downlink to the Experiment Monitoring Area located in Space Station Processing Facility at NASA's Kennedy Space Center in Florida. Image Credit: NASA

Veggie team members in monitor Veg-03 activation aboard the International Space Station via a live video downlink to the Experiment Monitoring Area located in Space Station Processing Facility at NASA’s Kennedy Space Center in Florida. Image Credit: NASA

October 25, 2016 – This morning, NASA astronaut Shane Kimbrough initiated the third crop of red romaine lettuce to be grown in space using the vegetable production system (“Veggie”) on the International Space Station.

The Veggie system was developed by Orbital Technologies Corp. (ORBITEC) of Madison, Wisconsin, a wholly-owned subsidiary of Sierra Nevada Corporation. ORBITEC and NASA have collaborated on the design and development of the Veggie system, which has resulted in the plant pillow concept.

Pillows of different sizes have been designed to accommodate a wide variety of plant types and different types of growing media. At the Space Station Processing Center at Kennedy Space Center, the Veggie team sanitizes the seeds and plants them in a “wick” that is inserted into each of the pillows. A precise amount of calcined clay (space dirt) and fertilizer is added to each pillow and the gas-impermeable pillow is then sealed by sewing the open end shut.

These particular plant pillows were packed and sent to the station in April 2016, along with twelve pillows of Chinese cabbage. The plant varieties are selected for their growth potential and flavor.

When crew members are ready to begin the Veggie experiment, they insert the plant pillows into the Veggie plant growth system, activate the system’s LED lights, add water, and regularly monitor and care for the growth of the plants. An identical set of pillows is activated in the Veggie ground control unit at Kennedy Space Center in a controlled-environment chamber.

The collapsible and expandable Veggie unit features a flat panel light bank that includes red, blue and green LEDs for plant growth and crew observation. The purple/pinkish hue surrounding the plants in Veggie is the result of a combination of the red and blue lights, which are needed to get good plant growth and are also more efficient at emitting light than the green LEDs. Green LEDs were added so the plants look more edible.

The Plant Pillows growing lettuce during the Veg-01 experiment. Image Credit: NASA

The Plant Pillows growing lettuce during the Veg-01 experiment. Image Credit: NASA

Veg-03 will continue NASA’s deep-space plant growth research to benefit the Earth and the agency’s journey to Mars by expanding on previous validation tests.

The Veg-01 experiment launched in 2014 contained “Outredgeous” red romaine lettuce seeds that were grown by Colorado astronaut Steve Swanson. The lettuce leaves were harvested and brought back to Earth for testing. Discussions with space microbiologists, flight surgeons, and space food technologists indicated that the crew should be able to consume the fresh produce with precautionary sanitizing using on-orbit Prosan wipes since microbial levels in the returned samples were sufficiently low.

In August 2015, the Veggie experiment yielded fresh lettuce and Expedition 44 crew members, including Colorado astronaut Kjell Lindgren, became the first humans to sample food grown in space.

In the latest experiment, astronauts on the Veggie team will attempt a repetitive harvest technique termed, “Cut-and-Come-Again.” When the plants are approximately four weeks old, a portion of the leaves will be harvested for consumption and for use as science samples. The remaining leaves will be left intact, along with the core of the plant, so that it can continue to grow and produce additional lettuce. In this way, the Veggie team hopes that on-orbit crop yield will be increased.

Astronauts on future long-duration missions will need to be able to grow their own food to supplement their diets. There are also psychological benefits from nurturing plants and the joy of seeing something green and fresh grown in space.