Not a simple feat. Until now, the inability to grow food in space has been a huge factor in limiting space travel and colonization. On August 10th, the first lettuce crops were harvested and eaten in the International Space Station. The three astronauts who got to sample the food - Scott Kelly, Kjell Lindgren, and Kimiya Yui - pronounced themselves pleased.
More precisely, the lettuce grown was a variety of red romaine called 'Outredgous', and it was grown in a small capsule called Veg-01 – or 'Veggie'. Part of a longer-term NASA plant experiment, Veggie glows with a purple hue due to the 132 red, 32 green, and 32 blue LED grow lights used. The red and blue lights are what actually helps the plants grow – the green are in place to make the crops look more appetizing to the people who have to eat them. Veggie took years to create because of the unique atmospheric and gravity-based challenges faced on the ISS, and it has its own heat and air exchange systems.
The first plants were germinated in May of 2014, then grown, harvested and frozen for testing back on Earth. With no pathogens found, the second batch was planted on July 7th for this August 10th harvest date – half of the lettuce was cleaned with wipes and dressed with oil and balsamic vinegar before being eaten, while the other half was likewise frozen and will return to Earth for testing.
When perfected, being able to grow food in space opens up many new possibilities for long-duration space missions, including the travel to and colonization of Mars. The astronomical expense of packaging and shipping frequent, heavy supplies of food into space has been a prohibiting factor in longer space trips, while properly feeding astronauts has always been a challenge. Besides the clear practical benefits, this also represents a psychological advantage: Lindgren stated that having living crops around would add a welcome change to a space station where so much of their surroundings consist of white and metal materials, while the act of growing plants is expected to be relaxing use of time in space. As Dr Giola Massa of NASA has said, “The farther and longer humans go away from Earth, the greater the need to be able to grow plants for food, atmosphere recycling and psychological benefits.”
You can watch this first-ever experience here: http://www.popsci.com/watch-astronauts-eat-first-space-grown-salad