English: Marshall Porterfield, Life and Physical Sciences Division Director at NASA Headquarters, talks about the human body in microgravity and other life sciences at a NASA Social exploring science on the International Space Station at NASA Headquarters, Wednesday, Feb. 20, 2013 in Washington. The Vegetable Production System ("Veggie"), a container used for growing plants on the ISS, is pictured in the foreground. Veggie is a deployable plant growth unit capable of producing salad-type crops to provide the crew with a palatable, nutritious, and safe source of fresh food and a tool to support relaxation and recreation. Veggie provides lighting and nutrient delivery, but utilizes the cabin environment for temperature control and as a source of carbon dioxide to promote growth.