Unless this is actually used with some recycling on a long term basis, it's a net loss by weight. Just ship up some cooking oil. So I suspect it's entirely fo

Unless this is actually used with some recycling on a long term basis, it's a net loss by weight. Just ship up some cooking oil. So I suspect it's entirely for the practicality and scientific value for now. Lettuce, especially a hardy cultivar, is delicate but fast growing and parasite resistant. And not picky about the growth media usually. Potatoes are slow and I suspect they might start to rot on the space station before they got to full size. Hydroponic potatoes is possible but tricky. But I'm only making a guess from having grown these plants here on Earth. In regard to calories I've heard good things said about oats and switchgrass. Not many people's favourite staples but they grow like weeds under wide climatic conditions with minimal water.