Today's air traffic control systems are based partly on design principles developed by NIST, which in the early 20th century developed several radio technologies that made sea and air navigation much safer. These included the first "visual type" radio beacon for an instrument landing system, which enables an air crew to locate and land on a runway in poor visibility.
Weather forecasting was vastly improved in 1936 when NIST built a radiosonde, a balloon-borne instrument that increased the range and quantity of available weather data by transmitting information on cloud height and thickness, temperature, pressure, and other phenomena. Radiosondes still are used today.
NIST played a major role in a leading technical advance of the World War II era when it assisted in the design of early "smart weapons" systems used by the Allies. The most important of these weapons was the radio proximity fuse, which exploded a projectile when directly over its target, rather than on impact, making the weapon five to 20 times more effective.
The Global Positioning System and other communications and navigation technologies are more accurate thanks to improved timekeeping, a trend promoted by NIST's operation of the first atomic clock, which was based on the ammonia molecule, in 1949. Atomic clocks are based on the resonances, or vibrations, of atoms or molecules. NIST's latest atomic clock neither gains nor loses a second in nearly 20 million years.
Cryogenic refrigerators and the world's largest hydrogen liquefier are among the novel technologies resulting from NIST research on cryogenics, a branch of physics dealing with the production and effects of very low temperatures. Over the 20th century, this research has contributed to scientific, military, aerospace, industrial, and medical fields.
The first operational, internally programmed digital computer in the United States was built by NIST. Dedicated in 1950, the Standards Eastern Automatic Computer incorporated a number of engineering innovations, including a graphical display that produced the first computerized image in 1957. To input that image, NIST researchers built the first scanner.
Products ranging from compact disk players to missile guidance systems are made worldwide with voltmeters that are calibrated using standards based on technology developed by NIST in the 1980s. The new standard for the volt, which made use of a single, simple equation of physics, was more accurate, more stable, and much easier to use than its predecessors.