The red romaine lettuce astronauts grew on the ISS a few years ago aren't just as good as Earth-grown lettuce, they're also as nutritious. NASA's Gioia Massa, Christina Khodadad and their colleagues examined and analyzed three batches of lettuce grown on the space station between 2014 and 2016. They compared it to lettuce that they grew here at home under similar conditions -- in the same relative humidity, carbon dioxide concentration and temperature, among other things -- and determined that the level of nutrients between them is very similar.