Traditionally, space medicine has tackled medical problems associated with the space environment. Increasingly, however, space medicine also encompasses research conducted aboard space stations and vehicles. Medical research conducted in microgravity is making significant contributions to the understanding of the molecular structure of living things—a key to the development of new disease-fighting drugs. The scope of biological molecules includes proteins, polysaccharides and other carbohydrates, lipids and nucleic acids of biological origin, and those expressed in plant, animal, fungal, or bacteria systems. The precise structure of proteins and some other biologic molecules can be determined by diffracting X rays off crystalline forms of these molecules to create a visual image of the molecular structure. Determining the structure of these macromolecules—which allow living organisms to function—is essential to the design of new, more effective drugs against infectious diseases and other afflictions, such as AIDS, heart disease, cancer, diabetes...