Anything that travels faster than the speed of sound is described as “supersonic.” Supersonic transport refers to any vehicle that is able to carry passengers or cargo at these speeds. This is usually limited to air and space vehicles, which are free of the friction that land- and water-based vehicles encounter. Supersonic transport was pioneered in the 1950s. In modern times, it is mainly used by military aircraft, although commercial supersonic travel is also sometimes available.
The speed of sound is around 768 miles per hour (1235 km/hr), although this varies slightly depending on atmospheric conditions. This is the rate at which sound waves travel through the air. Both natural and man-made phenomena are capable of exceeding this speed. For example, lightning often precedes thunder during a storm because light travels faster than sound. The cracking of a bullwhip is also created when the end of the whip briefly exceeds the speed of sound.
This phenomenon is called “breaking the sound barrier” and is accompanied by an audible report, called a “sonic boom.” During World War II, some early jet aircraft were said to be able to achieve these speeds. The first official supersonic transport, however, was an experimental plane flown by test pilot Chuck Yeager in 1947. A plane moving at the speed of sound is said to be traveling at Mach 1. A plane moving at twice that speed is traveling at Mach 2, and so on; vehicles that travel at Mach 5 or higher are said to be “hypersonic.”
Advances in avionic engineering led to the creation of the commercial supersonic transport in the late 1970s. This aircraft was called the Concorde and could cross the Atlantic Ocean in just over three hours, as opposed to at least eight hours for a subsonic flight. Initially, supersonic transport was considered the future of passenger air travel. The planes were controversial, however, because of noise and environmental concerns. The aircraft’s economic advantages were not great, and after a French Concorde crash in 2000, the aircraft were retired in favor of more conventional modern jets.
Supersonic jet aircraft are used in the military forces of nations around the world. They are mainly employed in fighter aircraft, which require great speed and maneuverability. Spacecraft also achieve supersonic speeds during takeoff and re-entry. The U.S. space shuttle program, like the Concorde, was retired in 2011. As commercial space travel becomes more common in the future, however, civilians will once again be able to enjoy supersonic transport.