Nutritional Biochemistry Laboratory (NBL) is one of the Life Sciences Reascarch Laboratories at the Johnson space Center in Houston. The primary responsibility of the NBL is the definition of the nutritional requirements for long-term space flight. To this end, studies have been conducted of energy, protein, and calcium metabolism as well as fluid and electrolyte homeostasis, and red blood cell synthesis and metabolism during space flight. The NBL is also charged with conducting nutritional assessment before, during, and after extended-duration missions to ensure maintenance of crew health for missions longer than 30 days.