The crew members have grown "Outredgeous" red romaine lettuce using the Veggie plant growth system, using red, blue and green LEDs.
The astronauts had to clean the greens with citric acid-based, food safe sanitizing wipes before consuming them. They will eat half, setting aside the other half to be packaged and frozen on the station until it can be returned to Earth for scientific analysis.
NASA's plant experiment, called Veg-01, is being used to study the in-orbit function and performance of the plant growth facility and its rooting "pillows," which contain the seeds.
NASA is developing the Veggie technology aboard the space station to provide future pioneers with a sustainable food supplement – a critical part of NASA’s Journey to Mars.
As NASA moves toward long-duration exploration missions farther into the solar system, Veggie will be a resource for crew food growth and consumption, and it also could be used by astronauts for recreational gardening activities during deep space missions, NASA said.